- tmp/tmpsfewi5k7/{from.md → to.md} +1771 -2318
tmp/tmpsfewi5k7/{from.md → to.md}
RENAMED
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@@ -5,118 +5,65 @@
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This Clause describes components that C++ programs may use to perform
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seminumerical operations.
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The following subclauses describe components for complex number types,
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random number generation, numeric ( *n*-at-a-time) arrays, generalized
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numeric algorithms, and mathematical
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as summarized in
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**Table: Numerics library summary** <a id="
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| Subclause | | Header |
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| ------------------------ | ------------------------------ | ------------ |
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| [[numerics.defns]] | Definitions | |
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| [[numeric.requirements]] | Requirements | |
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| [[cfenv]] | Floating-point environment | `<cfenv>` |
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| [[complex.numbers]] | Complex numbers | `<complex>` |
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| [[rand]] | Random number generation | `<random>` |
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| [[numarray]] | Numeric arrays | `<valarray>` |
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| [[
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| [[
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| | floating-point types | `<cstdlib>` |
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## Definitions <a id="numerics.defns">[[numerics.defns]]</a>
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-
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Define `GENERALIZED_NONCOMMUTATIVE_SUM(op, a1, ..., aN)` as follows:
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-
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- `a1` when `N` is `1`, otherwise
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- `op(GENERALIZED_NONCOMMUTATIVE_SUM(op, a1, ..., aK),`
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`\phantom{op(}GENERALIZED_NONCOMMUTATIVE_SUM(op, aM, ..., aN))` for
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any `K` where 1 < K+1 = M ≤ N.
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-
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Define `GENERALIZED_SUM(op, a1, ..., aN)` as
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`GENERALIZED_NONCOMMUTATIVE_SUM(op, b1, ..., bN)`, where `b1, ..., bN`
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may be any permutation of `a1, ..., aN`.
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-
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## Numeric type requirements <a id="numeric.requirements">[[numeric.requirements]]</a>
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The `complex` and `valarray` components are parameterized by the type of
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information they contain and manipulate. A C++ program shall instantiate
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these components only with a type
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-
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-
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-
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-
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- `T` is not a reference type;
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- `T` is not cv-qualified;
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- If `T` is a class, it has a public default constructor;
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- If `T` is a class, it has a public copy constructor with the signature
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`T::T(const T&)`
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- If `T` is a class, it has a public destructor;
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- If `T` is a class, it has a public assignment operator whose signature
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is either `T& T::operator=(const T&)` or `T& T::operator=(T)`
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- If `T` is a class, its assignment operator, copy and default
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constructors, and destructor shall correspond to each other in the
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following sense:
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- Initialization of raw storage using the copy constructor on the
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value of `T()`, however obtained, is semantically equivalent to
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value-initialization of the same raw storage.
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- Initialization of raw storage using the default constructor,
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followed by assignment, is semantically equivalent to initialization
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of raw storage using the copy constructor.
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- Destruction of an object, followed by initialization of its raw
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storage using the copy constructor, is semantically equivalent to
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assignment to the original object.
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-
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\[*Note 1*:
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This rule states, in part, that there shall not be any subtle
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differences in the semantics of initialization versus assignment. This
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gives an implementation considerable flexibility in how arrays are
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initialized.
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\[*Example 1*:
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An implementation is allowed to initialize a `valarray` by allocating
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storage using the `new` operator (which implies a call to the default
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constructor for each element) and then assigning each element its
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value. Or the implementation can allocate raw storage and use the copy
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constructor to initialize each element.
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— *end example*]
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If the distinction between initialization and assignment is important
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for a class, or if it fails to satisfy any of the other conditions
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listed above, the programmer should use `vector` ([[vector]]) instead
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of `valarray` for that class.
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— *end note*]
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- If `T` is a class, it does not overload unary `operator&`.
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If any operation on `T` throws an exception the effects are undefined.
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In addition, many member and related functions of `valarray<T>` can be
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successfully instantiated and will exhibit well-defined behavior if and
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only if `T`
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-
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[*Example
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`operator>()` will not be successfully instantiated for
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`valarray<complex>` operands, since `complex` does not have any ordering
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operators. — *end example*]
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## The floating-point environment <a id="cfenv">[[cfenv]]</a>
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### Header `<cfenv>` synopsis <a id="cfenv.syn">[[cfenv.syn]]</a>
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``` cpp
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#define FE_ALL_EXCEPT see below
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#define FE_DIVBYZERO see below
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#define FE_INEXACT see below
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#define FE_INVALID see below
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#define FE_OVERFLOW see below
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#define FE_UNDERFLOW see below
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#define FE_DOWNWARD see below
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#define FE_TONEAREST see below
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#define FE_TOWARDZERO see below
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#define FE_UPWARD see below
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#define FE_DFL_ENV see below
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namespace std {
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// types
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@@ -141,125 +88,117 @@ namespace std {
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```
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The contents and meaning of the header `<cfenv>` are the same as the C
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standard library header `<fenv.h>`.
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[*Note 1*: This
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-
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-
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-
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-
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-
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the
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-
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-
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The floating-point environment has thread storage duration
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[[basic.stc.thread]]
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environment is the state of the floating-point environment of the thread
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that constructs the corresponding `thread` object
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[[thread.thread.class]]
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[*Note 2*: That is, the child thread gets the floating-point state of
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the parent thread at the time of the child’s creation. — *end note*]
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A separate floating-point environment
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-
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ISO C 7.6
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## Complex numbers <a id="complex.numbers">[[complex.numbers]]</a>
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The header `<complex>` defines a class template, and numerous functions
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for representing and manipulating complex numbers.
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The effect of instantiating the template `complex` for any type other
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than `float`, `double`, or `long double` is unspecified. The
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specializations `complex<float>`, `complex<double>`, and
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`complex<long double>` are literal types
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If the result of a function is not mathematically defined or not in the
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range of representable values for its type, the behavior is undefined.
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If `z` is an lvalue
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- the expression `reinterpret_cast<cv T(&)[2]>(z)`
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- `reinterpret_cast<cv T(&)[2]>(z)[0]`
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-
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- `reinterpret_cast<cv T(&)[2]>(z)[1]`
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-
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Moreover, if `a` is an expression of type cv `complex<T>*` and the
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expression `a[i]` is well-defined for an integer expression `i`, then:
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- `reinterpret_cast<cv T*>(a)[2*i]`
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-
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- `reinterpret_cast<cv T*>(a)[2*i + 1]`
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-
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### Header `<complex>` synopsis <a id="complex.syn">[[complex.syn]]</a>
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``` cpp
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namespace std {
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template<class T> class complex;
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template<> class complex<float>;
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template<> class complex<double>;
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template<> class complex<long double>;
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// [complex.ops], operators
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template<class T>
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template<class T> complex<T> operator+(const
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template<class T> complex<T> operator+(const T&, const complex<T>&);
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template<class T> complex<T> operator-(
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template<class T> complex<T> operator-(const
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template<class T> complex<T> operator-(const T&, const complex<T>&);
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template<class T> complex<T> operator*(
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template<class T> complex<T> operator*(const
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template<class T> complex<T> operator*(const T&, const complex<T>&);
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template<class T> complex<T> operator/(
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template<class T> complex<T> operator/(const
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template<class T> complex<T> operator/(const T&, const complex<T>&);
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template<class T> complex<T> operator+(const complex<T>&);
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template<class T> complex<T> operator-(const complex<T>&);
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template<class T> constexpr bool operator==(
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const complex<T>&, const complex<T>&);
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template<class T> constexpr bool operator==(const complex<T>&, const T&);
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template<class T> constexpr bool operator==(const T&, const complex<T>&);
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template<class T> constexpr bool operator!=(const complex<T>&, const complex<T>&);
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template<class T> constexpr bool operator!=(const complex<T>&, const T&);
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template<class T> constexpr bool operator!=(const T&, const complex<T>&);
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template<class T, class charT, class traits>
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-
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operator>>(basic_istream<charT, traits>&, complex<T>&);
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template<class T, class charT, class traits>
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-
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operator<<(basic_ostream<charT, traits>&, const complex<T>&);
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// [complex.value.ops], values
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template<class T> constexpr T real(const complex<T>&);
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template<class T> constexpr T imag(const complex<T>&);
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template<class T> T abs(const complex<T>&);
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template<class T> T arg(const complex<T>&);
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template<class T> T norm(const complex<T>&);
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template<class T> complex<T> conj(const complex<T>&);
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template<class T> complex<T> proj(const complex<T>&);
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template<class T> complex<T> polar(const T&, const T& =
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// [complex.transcendentals], transcendentals
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template<class T> complex<T> acos(const complex<T>&);
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template<class T> complex<T> asin(const complex<T>&);
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template<class T> complex<T> atan(const complex<T>&);
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@@ -300,148 +239,148 @@ namespace std {
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### Class template `complex` <a id="complex">[[complex]]</a>
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``` cpp
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namespace std {
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template<class T>
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class complex {
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public:
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using value_type = T;
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constexpr complex(const T& re = T(), const T& im = T());
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constexpr complex(const complex&);
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template<class X> constexpr complex(const complex<X>&);
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constexpr T real() const;
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void real(T);
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constexpr T imag() const;
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void imag(T);
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complex
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complex
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complex
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complex
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complex
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complex& operator=(const complex&);
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template<class X> complex
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template<class X> complex
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template<class X> complex
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template<class X> complex
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template<class X> complex
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};
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}
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```
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The class `complex` describes an object that can store the Cartesian
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components, `real()` and `imag()`, of a complex number.
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###
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``` cpp
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namespace std {
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template<> class complex<float> {
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public:
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using value_type = float;
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constexpr complex(float re = 0.0f, float im = 0.0f);
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constexpr explicit complex(const complex<double>&);
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constexpr explicit complex(const complex<long double>&);
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constexpr float real() const;
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void real(float);
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constexpr float imag() const;
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void imag(float);
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complex
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complex
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complex
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complex
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complex
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complex
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template<class X> complex
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template<class X> complex
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template<class X> complex
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template<class X> complex
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template<class X> complex
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};
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template<> class complex<double> {
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public:
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using value_type = double;
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constexpr complex(double re = 0.0, double im = 0.0);
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constexpr complex(const complex<float>&);
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constexpr explicit complex(const complex<long double>&);
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constexpr double real() const;
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-
void real(double);
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constexpr double imag() const;
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-
void imag(double);
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-
complex
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-
complex
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-
complex
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-
complex
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-
complex
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-
complex
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template<class X> complex
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template<class X> complex
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-
template<class X> complex
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-
template<class X> complex
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-
template<class X> complex
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};
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template<> class complex<long double> {
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public:
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using value_type = long double;
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constexpr complex(long double re = 0.0L, long double im = 0.0L);
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constexpr complex(const complex<float>&);
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constexpr complex(const complex<double>&);
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constexpr long double real() const;
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-
void real(long double);
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constexpr long double imag() const;
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-
void imag(long double);
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-
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-
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-
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-
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-
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-
complex<long double>& operator/=(long double);
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-
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-
template<class X>
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-
template<class X>
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-
template<class X>
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-
template<class X>
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};
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}
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```
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-
###
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| 427 |
``` cpp
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template<class T> constexpr complex(const T& re = T(), const T& im = T());
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```
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-
*
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-
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-
*Postconditions:* `real() == re && imag() == im`.
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``` cpp
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constexpr T real() const;
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```
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*Returns:* The value of the real component.
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``` cpp
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-
void real(T val);
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```
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*Effects:* Assigns `val` to the real component.
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``` cpp
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@@ -449,185 +388,170 @@ constexpr T imag() const;
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```
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*Returns:* The value of the imaginary component.
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``` cpp
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| 454 |
-
void imag(T val);
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```
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| 457 |
*Effects:* Assigns `val` to the imaginary component.
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-
###
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| 460 |
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| 461 |
``` cpp
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| 462 |
-
complex
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```
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| 464 |
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| 465 |
*Effects:* Adds the scalar value `rhs` to the real part of the complex
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value `*this` and stores the result in the real part of `*this`, leaving
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the imaginary part unchanged.
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*Returns:* `*this`.
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``` cpp
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| 472 |
-
complex
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```
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| 474 |
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| 475 |
*Effects:* Subtracts the scalar value `rhs` from the real part of the
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complex value `*this` and stores the result in the real part of `*this`,
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leaving the imaginary part unchanged.
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| 478 |
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| 479 |
*Returns:* `*this`.
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| 480 |
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| 481 |
``` cpp
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| 482 |
-
complex
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```
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| 484 |
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| 485 |
*Effects:* Multiplies the scalar value `rhs` by the complex value
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| 486 |
`*this` and stores the result in `*this`.
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*Returns:* `*this`.
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``` cpp
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-
complex
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```
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| 493 |
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| 494 |
*Effects:* Divides the scalar value `rhs` into the complex value `*this`
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| 495 |
and stores the result in `*this`.
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| 496 |
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*Returns:* `*this`.
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|
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``` cpp
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| 500 |
-
template<class X> complex
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| 501 |
```
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| 502 |
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| 503 |
*Effects:* Adds the complex value `rhs` to the complex value `*this` and
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stores the sum in `*this`.
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*Returns:* `*this`.
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|
| 508 |
``` cpp
|
| 509 |
-
template<class X> complex
|
| 510 |
```
|
| 511 |
|
| 512 |
*Effects:* Subtracts the complex value `rhs` from the complex value
|
| 513 |
`*this` and stores the difference in `*this`.
|
| 514 |
|
| 515 |
*Returns:* `*this`.
|
| 516 |
|
| 517 |
``` cpp
|
| 518 |
-
template<class X> complex
|
| 519 |
```
|
| 520 |
|
| 521 |
*Effects:* Multiplies the complex value `rhs` by the complex value
|
| 522 |
`*this` and stores the product in `*this`.
|
| 523 |
|
| 524 |
*Returns:* `*this`.
|
| 525 |
|
| 526 |
``` cpp
|
| 527 |
-
template<class X> complex
|
| 528 |
```
|
| 529 |
|
| 530 |
*Effects:* Divides the complex value `rhs` into the complex value
|
| 531 |
`*this` and stores the quotient in `*this`.
|
| 532 |
|
| 533 |
*Returns:* `*this`.
|
| 534 |
|
| 535 |
-
###
|
| 536 |
|
| 537 |
``` cpp
|
| 538 |
-
template<class T> complex<T> operator+(const complex<T>& lhs);
|
| 539 |
```
|
| 540 |
|
| 541 |
*Returns:* `complex<T>(lhs)`.
|
| 542 |
|
| 543 |
-
*Remarks:* unary operator.
|
| 544 |
-
|
| 545 |
``` cpp
|
| 546 |
-
template<class T> complex<T> operator+(const complex<T>& lhs, const complex<T>& rhs);
|
| 547 |
-
template<class T> complex<T> operator+(const complex<T>& lhs, const T& rhs);
|
| 548 |
-
template<class T> complex<T> operator+(const T& lhs, const complex<T>& rhs);
|
| 549 |
```
|
| 550 |
|
| 551 |
*Returns:* `complex<T>(lhs) += rhs`.
|
| 552 |
|
| 553 |
``` cpp
|
| 554 |
-
template<class T> complex<T> operator-(const complex<T>& lhs);
|
| 555 |
```
|
| 556 |
|
| 557 |
*Returns:* `complex<T>(-lhs.real(),-lhs.imag())`.
|
| 558 |
|
| 559 |
-
*Remarks:* unary operator.
|
| 560 |
-
|
| 561 |
``` cpp
|
| 562 |
-
template<class T> complex<T> operator-(const complex<T>& lhs, const complex<T>& rhs);
|
| 563 |
-
template<class T> complex<T> operator-(const complex<T>& lhs, const T& rhs);
|
| 564 |
-
template<class T> complex<T> operator-(const T& lhs, const complex<T>& rhs);
|
| 565 |
```
|
| 566 |
|
| 567 |
*Returns:* `complex<T>(lhs) -= rhs`.
|
| 568 |
|
| 569 |
``` cpp
|
| 570 |
-
template<class T> complex<T> operator*(const complex<T>& lhs, const complex<T>& rhs);
|
| 571 |
-
template<class T> complex<T> operator*(const complex<T>& lhs, const T& rhs);
|
| 572 |
-
template<class T> complex<T> operator*(const T& lhs, const complex<T>& rhs);
|
| 573 |
```
|
| 574 |
|
| 575 |
*Returns:* `complex<T>(lhs) *= rhs`.
|
| 576 |
|
| 577 |
``` cpp
|
| 578 |
-
template<class T> complex<T> operator/(const complex<T>& lhs, const complex<T>& rhs);
|
| 579 |
-
template<class T> complex<T> operator/(const complex<T>& lhs, const T& rhs);
|
| 580 |
-
template<class T> complex<T> operator/(const T& lhs, const complex<T>& rhs);
|
| 581 |
```
|
| 582 |
|
| 583 |
*Returns:* `complex<T>(lhs) /= rhs`.
|
| 584 |
|
| 585 |
``` cpp
|
| 586 |
template<class T> constexpr bool operator==(const complex<T>& lhs, const complex<T>& rhs);
|
| 587 |
template<class T> constexpr bool operator==(const complex<T>& lhs, const T& rhs);
|
| 588 |
-
template<class T> constexpr bool operator==(const T& lhs, const complex<T>& rhs);
|
| 589 |
```
|
| 590 |
|
| 591 |
*Returns:* `lhs.real() == rhs.real() && lhs.imag() == rhs.imag()`.
|
| 592 |
|
| 593 |
*Remarks:* The imaginary part is assumed to be `T()`, or 0.0, for the
|
| 594 |
`T` arguments.
|
| 595 |
|
| 596 |
-
``` cpp
|
| 597 |
-
template<class T> constexpr bool operator!=(const complex<T>& lhs, const complex<T>& rhs);
|
| 598 |
-
template<class T> constexpr bool operator!=(const complex<T>& lhs, const T& rhs);
|
| 599 |
-
template<class T> constexpr bool operator!=(const T& lhs, const complex<T>& rhs);
|
| 600 |
-
```
|
| 601 |
-
|
| 602 |
-
*Returns:* `rhs.real() != lhs.real() || rhs.imag() != lhs.imag()`.
|
| 603 |
-
|
| 604 |
``` cpp
|
| 605 |
template<class T, class charT, class traits>
|
| 606 |
-
basic_istream<charT, traits>&
|
| 607 |
-
operator>>(basic_istream<charT, traits>& is, complex<T>& x);
|
| 608 |
```
|
| 609 |
|
| 610 |
-
*
|
| 611 |
|
| 612 |
*Effects:* Extracts a complex number `x` of the form: `u`, `(u)`, or
|
| 613 |
`(u,v)`, where `u` is the real part and `v` is the imaginary
|
| 614 |
-
part
|
| 615 |
|
| 616 |
If bad input is encountered, calls `is.setstate(ios_base::failbit)`
|
| 617 |
-
(which may throw `
|
| 618 |
|
| 619 |
*Returns:* `is`.
|
| 620 |
|
| 621 |
*Remarks:* This extraction is performed as a series of simpler
|
| 622 |
extractions. Therefore, the skipping of whitespace is specified to be
|
| 623 |
the same for each of the simpler extractions.
|
| 624 |
|
| 625 |
``` cpp
|
| 626 |
template<class T, class charT, class traits>
|
| 627 |
-
basic_ostream<charT, traits>&
|
| 628 |
-
operator<<(basic_ostream<charT, traits>& o, const complex<T>& x);
|
| 629 |
```
|
| 630 |
|
| 631 |
*Effects:* Inserts the complex number `x` onto the stream `o` as if it
|
| 632 |
were implemented as follows:
|
| 633 |
|
|
@@ -644,11 +568,11 @@ return o << s.str();
|
|
| 644 |
character, the use of comma as a field separator can be ambiguous.
|
| 645 |
Inserting `showpoint` into the output stream forces all outputs to show
|
| 646 |
an explicit decimal point character; as a result, all inserted sequences
|
| 647 |
of complex numbers can be extracted unambiguously. — *end note*]
|
| 648 |
|
| 649 |
-
###
|
| 650 |
|
| 651 |
``` cpp
|
| 652 |
template<class T> constexpr T real(const complex<T>& x);
|
| 653 |
```
|
| 654 |
|
|
@@ -671,89 +595,94 @@ template<class T> T arg(const complex<T>& x);
|
|
| 671 |
```
|
| 672 |
|
| 673 |
*Returns:* The phase angle of `x`, or `atan2(imag(x), real(x))`.
|
| 674 |
|
| 675 |
``` cpp
|
| 676 |
-
template<class T> T norm(const complex<T>& x);
|
| 677 |
```
|
| 678 |
|
| 679 |
*Returns:* The squared magnitude of `x`.
|
| 680 |
|
| 681 |
``` cpp
|
| 682 |
-
template<class T> complex<T> conj(const complex<T>& x);
|
| 683 |
```
|
| 684 |
|
| 685 |
*Returns:* The complex conjugate of `x`.
|
| 686 |
|
| 687 |
``` cpp
|
| 688 |
template<class T> complex<T> proj(const complex<T>& x);
|
| 689 |
```
|
| 690 |
|
| 691 |
*Returns:* The projection of `x` onto the Riemann sphere.
|
| 692 |
|
| 693 |
-
*Remarks:* Behaves the same as the C function `cproj`
|
| 694 |
-
7.3.9.
|
| 695 |
|
| 696 |
``` cpp
|
| 697 |
-
template<class T> complex<T> polar(const T& rho, const T& theta =
|
| 698 |
```
|
| 699 |
|
| 700 |
-
*
|
| 701 |
-
finite.
|
| 702 |
|
| 703 |
*Returns:* The `complex` value corresponding to a complex number whose
|
| 704 |
magnitude is `rho` and whose phase angle is `theta`.
|
| 705 |
|
| 706 |
-
###
|
| 707 |
|
| 708 |
``` cpp
|
| 709 |
template<class T> complex<T> acos(const complex<T>& x);
|
| 710 |
```
|
| 711 |
|
| 712 |
*Returns:* The complex arc cosine of `x`.
|
| 713 |
|
| 714 |
-
*Remarks:* Behaves the same as C function `cacos`
|
|
|
|
| 715 |
|
| 716 |
``` cpp
|
| 717 |
template<class T> complex<T> asin(const complex<T>& x);
|
| 718 |
```
|
| 719 |
|
| 720 |
*Returns:* The complex arc sine of `x`.
|
| 721 |
|
| 722 |
-
*Remarks:* Behaves the same as C function `casin`
|
|
|
|
| 723 |
|
| 724 |
``` cpp
|
| 725 |
template<class T> complex<T> atan(const complex<T>& x);
|
| 726 |
```
|
| 727 |
|
| 728 |
*Returns:* The complex arc tangent of `x`.
|
| 729 |
|
| 730 |
-
*Remarks:* Behaves the same as C function `catan`
|
|
|
|
| 731 |
|
| 732 |
``` cpp
|
| 733 |
template<class T> complex<T> acosh(const complex<T>& x);
|
| 734 |
```
|
| 735 |
|
| 736 |
*Returns:* The complex arc hyperbolic cosine of `x`.
|
| 737 |
|
| 738 |
-
*Remarks:* Behaves the same as C function `cacosh`
|
|
|
|
| 739 |
|
| 740 |
``` cpp
|
| 741 |
template<class T> complex<T> asinh(const complex<T>& x);
|
| 742 |
```
|
| 743 |
|
| 744 |
*Returns:* The complex arc hyperbolic sine of `x`.
|
| 745 |
|
| 746 |
-
*Remarks:* Behaves the same as C function `casinh`
|
|
|
|
| 747 |
|
| 748 |
``` cpp
|
| 749 |
template<class T> complex<T> atanh(const complex<T>& x);
|
| 750 |
```
|
| 751 |
|
| 752 |
*Returns:* The complex arc hyperbolic tangent of `x`.
|
| 753 |
|
| 754 |
-
*Remarks:* Behaves the same as C function `catanh`
|
|
|
|
| 755 |
|
| 756 |
``` cpp
|
| 757 |
template<class T> complex<T> cos(const complex<T>& x);
|
| 758 |
```
|
| 759 |
|
|
@@ -774,12 +703,14 @@ template<class T> complex<T> exp(const complex<T>& x);
|
|
| 774 |
``` cpp
|
| 775 |
template<class T> complex<T> log(const complex<T>& x);
|
| 776 |
```
|
| 777 |
|
| 778 |
*Returns:* The complex natural (base-e) logarithm of `x`. For all `x`,
|
| 779 |
-
`imag(log(x))` lies in the interval \[-π, π\]
|
| 780 |
-
|
|
|
|
|
|
|
| 781 |
|
| 782 |
*Remarks:* The branch cuts are along the negative real axis.
|
| 783 |
|
| 784 |
``` cpp
|
| 785 |
template<class T> complex<T> log10(const complex<T>& x);
|
|
@@ -817,12 +748,14 @@ template<class T> complex<T> sinh(const complex<T>& x);
|
|
| 817 |
``` cpp
|
| 818 |
template<class T> complex<T> sqrt(const complex<T>& x);
|
| 819 |
```
|
| 820 |
|
| 821 |
*Returns:* The complex square root of `x`, in the range of the right
|
| 822 |
-
half-plane.
|
| 823 |
-
|
|
|
|
|
|
|
| 824 |
|
| 825 |
*Remarks:* The branch cuts are along the negative real axis.
|
| 826 |
|
| 827 |
``` cpp
|
| 828 |
template<class T> complex<T> tan(const complex<T>& x);
|
|
@@ -844,38 +777,40 @@ The following function templates shall have additional overloads:
|
|
| 844 |
arg norm
|
| 845 |
conj proj
|
| 846 |
imag real
|
| 847 |
```
|
| 848 |
|
|
|
|
|
|
|
| 849 |
The additional overloads shall be sufficient to ensure:
|
| 850 |
|
| 851 |
-
|
| 852 |
-
|
| 853 |
-
|
| 854 |
-
|
| 855 |
-
|
| 856 |
cast to `complex<float>`.
|
| 857 |
|
| 858 |
Function template `pow` shall have additional overloads sufficient to
|
| 859 |
ensure, for a call with at least one argument of type `complex<T>`:
|
| 860 |
|
| 861 |
-
|
| 862 |
double`, then both arguments are effectively cast to
|
| 863 |
`complex<long double>`.
|
| 864 |
-
|
| 865 |
-
|
| 866 |
`complex<double>`.
|
| 867 |
-
|
| 868 |
then both arguments are effectively cast to `complex<float>`.
|
| 869 |
|
| 870 |
### Suffixes for complex number literals <a id="complex.literals">[[complex.literals]]</a>
|
| 871 |
|
| 872 |
-
This
|
| 873 |
-
literals. The suffixes `i`, `il`, and `if` create complex numbers
|
| 874 |
-
types `complex<double>`, `complex<long double>`, and
|
| 875 |
-
respectively, with their imaginary part denoted by the
|
| 876 |
-
number and the real part being zero.
|
| 877 |
|
| 878 |
``` cpp
|
| 879 |
constexpr complex<long double> operator""il(long double d);
|
| 880 |
constexpr complex<long double> operator""il(unsigned long long d);
|
| 881 |
```
|
|
@@ -894,57 +829,482 @@ constexpr complex<float> operator""if(long double d);
|
|
| 894 |
constexpr complex<float> operator""if(unsigned long long d);
|
| 895 |
```
|
| 896 |
|
| 897 |
*Returns:* `complex<float>{0.0f, static_cast<float>(d)}`.
|
| 898 |
|
|
|
|
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|
| 899 |
## Random number generation <a id="rand">[[rand]]</a>
|
| 900 |
|
| 901 |
This subclause defines a facility for generating (pseudo-)random
|
| 902 |
numbers.
|
| 903 |
|
| 904 |
In addition to a few utilities, four categories of entities are
|
| 905 |
described: *uniform random bit generators*, *random number engines*,
|
| 906 |
*random number engine adaptors*, and *random number distributions*.
|
| 907 |
-
These categorizations are applicable to types that
|
| 908 |
corresponding requirements, to objects instantiated from such types, and
|
| 909 |
to templates producing such types when instantiated.
|
| 910 |
|
| 911 |
[*Note 1*: These entities are specified in such a way as to permit the
|
| 912 |
binding of any uniform random bit generator object `e` as the argument
|
| 913 |
to any random number distribution object `d`, thus producing a
|
| 914 |
zero-argument function object such as given by
|
| 915 |
`bind(d,e)`. — *end note*]
|
| 916 |
|
| 917 |
Each of the entities specified via this subclause has an associated
|
| 918 |
-
arithmetic type
|
| 919 |
-
|
| 920 |
entity is characterized:
|
| 921 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 922 |
If integer-valued, an entity may optionally be further characterized as
|
| 923 |
*signed* or *unsigned*, according to `numeric_limits<T>::is_signed`.
|
| 924 |
|
| 925 |
Unless otherwise specified, all descriptions of calculations in this
|
| 926 |
subclause use mathematical real numbers.
|
| 927 |
|
| 928 |
-
Throughout this subclause, the operators , , and denote the
|
| 929 |
-
conventional bitwise operations. Further:
|
|
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|
| 930 |
|
| 931 |
### Requirements <a id="rand.req">[[rand.req]]</a>
|
| 932 |
|
| 933 |
#### General requirements <a id="rand.req.genl">[[rand.req.genl]]</a>
|
| 934 |
|
| 935 |
Throughout this subclause [[rand]], the effect of instantiating a
|
| 936 |
template:
|
| 937 |
|
|
|
|
|
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|
| 938 |
Throughout this subclause [[rand]], phrases of the form “`x` is an
|
| 939 |
iterator of a specific kind” shall be interpreted as equivalent to the
|
| 940 |
-
more formal requirement that “`x` is a value of a type
|
| 941 |
requirements of the specified iterator type”.
|
| 942 |
|
| 943 |
Throughout this subclause [[rand]], any constructor that can be called
|
| 944 |
-
with a single argument and that
|
| 945 |
-
|
| 946 |
|
| 947 |
#### Seed sequence requirements <a id="rand.req.seedseq">[[rand.req.seedseq]]</a>
|
| 948 |
|
| 949 |
A *seed sequence* is an object that consumes a sequence of
|
| 950 |
integer-valued data and produces a requested number of unsigned integer
|
|
@@ -953,61 +1313,105 @@ values i, 0 ≤ i < 2³², based on the consumed data.
|
|
| 953 |
[*Note 1*: Such an object provides a mechanism to avoid replication of
|
| 954 |
streams of random variates. This can be useful, for example, in
|
| 955 |
applications requiring large numbers of random number
|
| 956 |
engines. — *end note*]
|
| 957 |
|
| 958 |
-
A class `S`
|
| 959 |
-
|
| 960 |
-
|
| 961 |
-
|
| 962 |
-
|
|
|
|
|
|
|
|
|
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|
|
|
|
|
|
|
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|
|
|
|
|
| 963 |
|
| 964 |
#### Uniform random bit generator requirements <a id="rand.req.urng">[[rand.req.urng]]</a>
|
| 965 |
|
| 966 |
A *uniform random bit generator* `g` of type `G` is a function object
|
| 967 |
returning unsigned integer values such that each value in the range of
|
| 968 |
possible results has (ideally) equal probability of being returned.
|
| 969 |
|
| 970 |
[*Note 1*: The degree to which `g`’s results approximate the ideal is
|
| 971 |
often determined statistically. — *end note*]
|
| 972 |
|
| 973 |
-
|
| 974 |
-
|
| 975 |
-
|
| 976 |
-
|
| 977 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 978 |
|
| 979 |
-
|
|
|
|
|
|
|
|
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|
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|
|
|
|
|
|
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|
|
|
|
|
|
|
|
| 980 |
|
| 981 |
#### Random number engine requirements <a id="rand.req.eng">[[rand.req.eng]]</a>
|
| 982 |
|
| 983 |
A *random number engine* (commonly shortened to *engine*) `e` of type
|
| 984 |
`E` is a uniform random bit generator that additionally meets the
|
| 985 |
requirements (e.g., for seeding and for input/output) specified in this
|
| 986 |
-
|
| 987 |
|
| 988 |
At any given time, `e` has a state eᵢ for some integer i ≥ 0. Upon
|
| 989 |
construction, `e` has an initial state e₀. An engine’s state may be
|
| 990 |
established via a constructor, a `seed` function, assignment, or a
|
| 991 |
suitable `operator>>`.
|
| 992 |
|
| 993 |
`E`’s specification shall define:
|
| 994 |
|
| 995 |
-
|
| 996 |
-
|
| 997 |
-
|
| 998 |
-
|
| 999 |
-
|
| 1000 |
-
|
| 1001 |
-
|
| 1002 |
-
|
| 1003 |
-
|
| 1004 |
-
|
| 1005 |
-
|
| 1006 |
-
[[
|
| 1007 |
-
|
| 1008 |
-
|
|
|
|
|
|
|
|
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|
|
|
|
|
|
| 1009 |
|
| 1010 |
#### Random number engine adaptor requirements <a id="rand.req.adapt">[[rand.req.adapt]]</a>
|
| 1011 |
|
| 1012 |
A *random number engine adaptor* (commonly shortened to *adaptor*) `a`
|
| 1013 |
of type `A` is a random number engine that takes values produced by some
|
|
@@ -1062,11 +1466,20 @@ void seed(result_type s);
|
|
| 1062 |
template<class Sseq> void seed(Sseq& q);
|
| 1063 |
```
|
| 1064 |
|
| 1065 |
*Effects:* With `b` as the base engine, invokes `b.seed(q)`.
|
| 1066 |
|
| 1067 |
-
`A` shall also
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1068 |
|
| 1069 |
#### Random number distribution requirements <a id="rand.req.dist">[[rand.req.dist]]</a>
|
| 1070 |
|
| 1071 |
A *random number distribution* (commonly shortened to *distribution*)
|
| 1072 |
`d` of type `D` is a function object returning values that are
|
|
@@ -1081,22 +1494,38 @@ distribution*. Such distribution parameters are identified in this
|
|
| 1081 |
context by writing, for example, p(z | a,b) or P(zᵢ | a,b), to name
|
| 1082 |
specific parameters, or by writing, for example, p(z |{`p`}) or
|
| 1083 |
P(zᵢ |{`p`}), to denote a distribution’s parameters `p` taken as a
|
| 1084 |
whole.
|
| 1085 |
|
| 1086 |
-
A class `D`
|
| 1087 |
-
|
| 1088 |
-
|
| 1089 |
-
|
| 1090 |
-
|
| 1091 |
|
| 1092 |
-
|
| 1093 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1094 |
|
| 1095 |
-
`
|
| 1096 |
-
[[
|
| 1097 |
-
|
|
|
|
|
|
|
|
|
|
| 1098 |
|
| 1099 |
The sequence of numbers produced by repeated invocations of `d(g)` shall
|
| 1100 |
be independent of any invocation of `os << d` or of any `const` member
|
| 1101 |
function of `D` between any of the invocations `d(g)`.
|
| 1102 |
|
|
@@ -1109,14 +1538,14 @@ produce the same sequence of numbers as would repeated invocations of
|
|
| 1109 |
It is unspecified whether `D::param_type` is declared as a (nested)
|
| 1110 |
`class` or via a `typedef`. In this subclause [[rand]], declarations of
|
| 1111 |
`D::param_type` are in the form of `typedef`s for convenience of
|
| 1112 |
exposition only.
|
| 1113 |
|
| 1114 |
-
`P` shall
|
| 1115 |
-
[[
|
| 1116 |
-
[[
|
| 1117 |
-
[[
|
| 1118 |
|
| 1119 |
For each of the constructors of `D` taking arguments corresponding to
|
| 1120 |
parameters of the distribution, `P` shall have a corresponding
|
| 1121 |
constructor subject to the same requirements and taking arguments
|
| 1122 |
identical in number, type, and default values. Moreover, for each of the
|
|
@@ -1128,178 +1557,41 @@ the identical name, type, and semantics.
|
|
| 1128 |
|
| 1129 |
``` cpp
|
| 1130 |
using distribution_type = D;
|
| 1131 |
```
|
| 1132 |
|
| 1133 |
-
### Header `<random>` synopsis <a id="rand.synopsis">[[rand.synopsis]]</a>
|
| 1134 |
-
|
| 1135 |
-
``` cpp
|
| 1136 |
-
#include <initializer_list>
|
| 1137 |
-
|
| 1138 |
-
namespace std {
|
| 1139 |
-
// [rand.eng.lcong], class template linear_congruential_engine
|
| 1140 |
-
template<class UIntType, UIntType a, UIntType c, UIntType m>
|
| 1141 |
-
class linear_congruential_engine;
|
| 1142 |
-
|
| 1143 |
-
// [rand.eng.mers], class template mersenne_twister_engine
|
| 1144 |
-
template<class UIntType, size_t w, size_t n, size_t m, size_t r,
|
| 1145 |
-
UIntType a, size_t u, UIntType d, size_t s,
|
| 1146 |
-
UIntType b, size_t t,
|
| 1147 |
-
UIntType c, size_t l, UIntType f>
|
| 1148 |
-
class mersenne_twister_engine;
|
| 1149 |
-
|
| 1150 |
-
// [rand.eng.sub], class template subtract_with_carry_engine
|
| 1151 |
-
template<class UIntType, size_t w, size_t s, size_t r>
|
| 1152 |
-
class subtract_with_carry_engine;
|
| 1153 |
-
|
| 1154 |
-
// [rand.adapt.disc], class template discard_block_engine
|
| 1155 |
-
template<class Engine, size_t p, size_t r>
|
| 1156 |
-
class discard_block_engine;
|
| 1157 |
-
|
| 1158 |
-
// [rand.adapt.ibits], class template independent_bits_engine
|
| 1159 |
-
template<class Engine, size_t w, class UIntType>
|
| 1160 |
-
class independent_bits_engine;
|
| 1161 |
-
|
| 1162 |
-
// [rand.adapt.shuf], class template shuffle_order_engine
|
| 1163 |
-
template<class Engine, size_t k>
|
| 1164 |
-
class shuffle_order_engine;
|
| 1165 |
-
|
| 1166 |
-
// [rand.predef], engines and engine adaptors with predefined parameters
|
| 1167 |
-
using minstd_rand0 = see below;
|
| 1168 |
-
using minstd_rand = see below;
|
| 1169 |
-
using mt19937 = see below;
|
| 1170 |
-
using mt19937_64 = see below;
|
| 1171 |
-
using ranlux24_base = see below;
|
| 1172 |
-
using ranlux48_base = see below;
|
| 1173 |
-
using ranlux24 = see below;
|
| 1174 |
-
using ranlux48 = see below;
|
| 1175 |
-
using knuth_b = see below;
|
| 1176 |
-
|
| 1177 |
-
using default_random_engine = see below;
|
| 1178 |
-
|
| 1179 |
-
// [rand.device], class random_device
|
| 1180 |
-
class random_device;
|
| 1181 |
-
|
| 1182 |
-
// [rand.util.seedseq], class seed_seq
|
| 1183 |
-
class seed_seq;
|
| 1184 |
-
|
| 1185 |
-
// [rand.util.canonical], function template generate_canonical
|
| 1186 |
-
template<class RealType, size_t bits, class URBG>
|
| 1187 |
-
RealType generate_canonical(URBG& g);
|
| 1188 |
-
|
| 1189 |
-
// [rand.dist.uni.int], class template uniform_int_distribution
|
| 1190 |
-
template<class IntType = int>
|
| 1191 |
-
class uniform_int_distribution;
|
| 1192 |
-
|
| 1193 |
-
// [rand.dist.uni.real], class template uniform_real_distribution
|
| 1194 |
-
template<class RealType = double>
|
| 1195 |
-
class uniform_real_distribution;
|
| 1196 |
-
|
| 1197 |
-
// [rand.dist.bern.bernoulli], class bernoulli_distribution
|
| 1198 |
-
class bernoulli_distribution;
|
| 1199 |
-
|
| 1200 |
-
// [rand.dist.bern.bin], class template binomial_distribution
|
| 1201 |
-
template<class IntType = int>
|
| 1202 |
-
class binomial_distribution;
|
| 1203 |
-
|
| 1204 |
-
// [rand.dist.bern.geo], class template geometric_distribution
|
| 1205 |
-
template<class IntType = int>
|
| 1206 |
-
class geometric_distribution;
|
| 1207 |
-
|
| 1208 |
-
// [rand.dist.bern.negbin], class template negative_binomial_distribution
|
| 1209 |
-
template<class IntType = int>
|
| 1210 |
-
class negative_binomial_distribution;
|
| 1211 |
-
|
| 1212 |
-
// [rand.dist.pois.poisson], class template poisson_distribution
|
| 1213 |
-
template<class IntType = int>
|
| 1214 |
-
class poisson_distribution;
|
| 1215 |
-
|
| 1216 |
-
// [rand.dist.pois.exp], class template exponential_distribution
|
| 1217 |
-
template<class RealType = double>
|
| 1218 |
-
class exponential_distribution;
|
| 1219 |
-
|
| 1220 |
-
// [rand.dist.pois.gamma], class template gamma_distribution
|
| 1221 |
-
template<class RealType = double>
|
| 1222 |
-
class gamma_distribution;
|
| 1223 |
-
|
| 1224 |
-
// [rand.dist.pois.weibull], class template weibull_distribution
|
| 1225 |
-
template<class RealType = double>
|
| 1226 |
-
class weibull_distribution;
|
| 1227 |
-
|
| 1228 |
-
// [rand.dist.pois.extreme], class template extreme_value_distribution
|
| 1229 |
-
template<class RealType = double>
|
| 1230 |
-
class extreme_value_distribution;
|
| 1231 |
-
|
| 1232 |
-
// [rand.dist.norm.normal], class template normal_distribution
|
| 1233 |
-
template<class RealType = double>
|
| 1234 |
-
class normal_distribution;
|
| 1235 |
-
|
| 1236 |
-
// [rand.dist.norm.lognormal], class template lognormal_distribution
|
| 1237 |
-
template<class RealType = double>
|
| 1238 |
-
class lognormal_distribution;
|
| 1239 |
-
|
| 1240 |
-
// [rand.dist.norm.chisq], class template chi_squared_distribution
|
| 1241 |
-
template<class RealType = double>
|
| 1242 |
-
class chi_squared_distribution;
|
| 1243 |
-
|
| 1244 |
-
// [rand.dist.norm.cauchy], class template cauchy_distribution
|
| 1245 |
-
template<class RealType = double>
|
| 1246 |
-
class cauchy_distribution;
|
| 1247 |
-
|
| 1248 |
-
// [rand.dist.norm.f], class template fisher_f_distribution
|
| 1249 |
-
template<class RealType = double>
|
| 1250 |
-
class fisher_f_distribution;
|
| 1251 |
-
|
| 1252 |
-
// [rand.dist.norm.t], class template student_t_distribution
|
| 1253 |
-
template<class RealType = double>
|
| 1254 |
-
class student_t_distribution;
|
| 1255 |
-
|
| 1256 |
-
// [rand.dist.samp.discrete], class template discrete_distribution
|
| 1257 |
-
template<class IntType = int>
|
| 1258 |
-
class discrete_distribution;
|
| 1259 |
-
|
| 1260 |
-
// [rand.dist.samp.pconst], class template piecewise_constant_distribution
|
| 1261 |
-
template<class RealType = double>
|
| 1262 |
-
class piecewise_constant_distribution;
|
| 1263 |
-
|
| 1264 |
-
// [rand.dist.samp.plinear], class template piecewise_linear_distribution
|
| 1265 |
-
template<class RealType = double>
|
| 1266 |
-
class piecewise_linear_distribution;
|
| 1267 |
-
}
|
| 1268 |
-
```
|
| 1269 |
-
|
| 1270 |
### Random number engine class templates <a id="rand.eng">[[rand.eng]]</a>
|
| 1271 |
|
| 1272 |
-
Each type instantiated from a class template specified in this
|
| 1273 |
-
[[rand.eng]]
|
| 1274 |
-
[[rand.req.eng]]
|
| 1275 |
|
| 1276 |
Except where specified otherwise, the complexity of each function
|
| 1277 |
-
specified in this
|
| 1278 |
|
| 1279 |
-
Except where specified otherwise, no function described in this
|
| 1280 |
-
[[rand.eng]] throws an exception.
|
| 1281 |
|
| 1282 |
-
Every function described in this
|
| 1283 |
function parameter `q` of type `Sseq&` for a template type parameter
|
| 1284 |
named `Sseq` that is different from type `seed_seq` throws what and when
|
| 1285 |
the invocation of `q.generate` throws.
|
| 1286 |
|
| 1287 |
-
Descriptions are provided in this
|
| 1288 |
-
operations that are not described in [[rand.req.eng]] or for
|
| 1289 |
-
where there is additional semantic information. In
|
| 1290 |
-
declarations for copy constructors, for copy assignment
|
| 1291 |
-
streaming operators, and for equality and inequality
|
| 1292 |
-
shown in the synopses.
|
| 1293 |
|
| 1294 |
-
Each template specified in this
|
| 1295 |
more relationships, involving the value(s) of its non-type template
|
| 1296 |
parameter(s), to hold. A program instantiating any of these templates is
|
| 1297 |
ill-formed if any such required relationship fails to hold.
|
| 1298 |
|
| 1299 |
For every random number engine and for every random number engine
|
| 1300 |
-
adaptor `X` defined in this subclause
|
| 1301 |
[[rand.adapt]]:
|
| 1302 |
|
| 1303 |
- if the constructor
|
| 1304 |
``` cpp
|
| 1305 |
template<class Sseq> explicit X(Sseq& q);
|
|
@@ -1343,11 +1635,12 @@ template<class UIntType, UIntType a, UIntType c, UIntType m>
|
|
| 1343 |
static constexpr result_type min() { return c == 0u ? 1u: 0u; }
|
| 1344 |
static constexpr result_type max() { return m - 1u; }
|
| 1345 |
static constexpr result_type default_seed = 1u;
|
| 1346 |
|
| 1347 |
// constructors and seeding functions
|
| 1348 |
-
|
|
|
|
| 1349 |
template<class Sseq> explicit linear_congruential_engine(Sseq& q);
|
| 1350 |
void seed(result_type s = default_seed);
|
| 1351 |
template<class Sseq> void seed(Sseq& q);
|
| 1352 |
|
| 1353 |
// generating functions
|
|
@@ -1355,41 +1648,38 @@ template<class UIntType, UIntType a, UIntType c, UIntType m>
|
|
| 1355 |
void discard(unsigned long long z);
|
| 1356 |
};
|
| 1357 |
```
|
| 1358 |
|
| 1359 |
If the template parameter `m` is 0, the modulus m used throughout this
|
| 1360 |
-
|
| 1361 |
-
1.
|
| 1362 |
|
| 1363 |
[*Note 1*: m need not be representable as a value of type
|
| 1364 |
`result_type`. — *end note*]
|
| 1365 |
|
| 1366 |
If the template parameter `m` is not 0, the following relations shall
|
| 1367 |
hold: `a < m` and `c < m`.
|
| 1368 |
|
| 1369 |
The textual representation consists of the value of xᵢ.
|
| 1370 |
|
| 1371 |
``` cpp
|
| 1372 |
-
explicit linear_congruential_engine(result_type s
|
| 1373 |
```
|
| 1374 |
|
| 1375 |
-
*Effects:*
|
| 1376 |
-
|
| 1377 |
-
otherwise sets the engine’s state to `s` mod m.
|
| 1378 |
|
| 1379 |
``` cpp
|
| 1380 |
template<class Sseq> explicit linear_congruential_engine(Sseq& q);
|
| 1381 |
```
|
| 1382 |
|
| 1383 |
-
*Effects:*
|
| 1384 |
-
|
| 1385 |
-
|
| 1386 |
-
|
| 1387 |
-
|
| 1388 |
-
|
| 1389 |
-
c mod m is 0 and S is 0, sets the engine’s state to 1, else sets the
|
| 1390 |
-
engine’s state to S.
|
| 1391 |
|
| 1392 |
#### Class template `mersenne_twister_engine` <a id="rand.eng.mers">[[rand.eng.mers]]</a>
|
| 1393 |
|
| 1394 |
A `mersenne_twister_engine` random number engine[^2] produces unsigned
|
| 1395 |
integer random numbers in the closed interval [0,2ʷ-1]. The state xᵢ of
|
|
@@ -1399,21 +1689,31 @@ applied to X are to be taken modulo n.
|
|
| 1399 |
|
| 1400 |
The transition algorithm employs a twisted generalized feedback shift
|
| 1401 |
register defined by shift values n and m, a twist value r, and a
|
| 1402 |
conditional xor-mask a. To improve the uniformity of the result, the
|
| 1403 |
bits of the raw shift register are additionally *tempered* (i.e.,
|
| 1404 |
-
scrambled) according to a bit-scrambling matrix defined by values
|
| 1405 |
-
|
| 1406 |
|
| 1407 |
The state transition is performed as follows:
|
| 1408 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1409 |
The sequence X is initialized with the help of an initialization
|
| 1410 |
multiplier f.
|
| 1411 |
|
| 1412 |
The generation algorithm determines the unsigned integer values
|
| 1413 |
z₁, z₂, z₃, z₄ as follows, then delivers z₄ as its result:
|
| 1414 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1415 |
``` cpp
|
| 1416 |
template<class UIntType, size_t w, size_t n, size_t m, size_t r,
|
| 1417 |
UIntType a, size_t u, UIntType d, size_t s,
|
| 1418 |
UIntType b, size_t t,
|
| 1419 |
UIntType c, size_t l, UIntType f>
|
|
@@ -1439,11 +1739,12 @@ template<class UIntType, size_t w, size_t n, size_t m, size_t r,
|
|
| 1439 |
static constexpr result_type min() { return 0; }
|
| 1440 |
static constexpr result_type max() { return 2^w - 1; }
|
| 1441 |
static constexpr result_type default_seed = 5489u;
|
| 1442 |
|
| 1443 |
// constructors and seeding functions
|
| 1444 |
-
|
|
|
|
| 1445 |
template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
|
| 1446 |
void seed(result_type value = default_seed);
|
| 1447 |
template<class Sseq> void seed(Sseq& q);
|
| 1448 |
|
| 1449 |
// generating functions
|
|
@@ -1457,18 +1758,18 @@ The following relations shall hold: `0 < m`, `m <= n`, `2u < w`,
|
|
| 1457 |
`w <= numeric_limits<UIntType>::digits`, `a <= (1u<<w) - 1u`,
|
| 1458 |
`b <= (1u<<w) - 1u`, `c <= (1u<<w) - 1u`, `d <= (1u<<w) - 1u`, and
|
| 1459 |
`f <= (1u<<w) - 1u`.
|
| 1460 |
|
| 1461 |
The textual representation of xᵢ consists of the values of
|
| 1462 |
-
|
| 1463 |
|
| 1464 |
``` cpp
|
| 1465 |
-
explicit mersenne_twister_engine(result_type value
|
| 1466 |
```
|
| 1467 |
|
| 1468 |
-
*Effects:*
|
| 1469 |
-
|
| 1470 |
\bigl[f \cdot
|
| 1471 |
\bigl(X_{i-1} \xor \bigl(X_{i-1} \rightshift (w-2)\bigr)
|
| 1472 |
\bigr)
|
| 1473 |
+ i \bmod n
|
| 1474 |
\bigr] \bmod 2^w
|
|
@@ -1478,14 +1779,13 @@ explicit mersenne_twister_engine(result_type value = default_seed);
|
|
| 1478 |
|
| 1479 |
``` cpp
|
| 1480 |
template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
|
| 1481 |
```
|
| 1482 |
|
| 1483 |
-
*Effects:*
|
| 1484 |
-
|
| 1485 |
-
|
| 1486 |
-
sets Xᵢ to
|
| 1487 |
$\left(\sum_{j=0}^{k-1}a_{k(i+n)+j} \cdot 2^{32j} \right) \bmod 2^w$.
|
| 1488 |
Finally, if the most significant w-r bits of X₋ₙ are zero, and if each
|
| 1489 |
of the other resulting Xᵢ is 0, changes X₋ₙ to 2ʷ⁻¹.
|
| 1490 |
|
| 1491 |
#### Class template `subtract_with_carry_engine` <a id="rand.eng.sub">[[rand.eng.sub]]</a>
|
|
@@ -1499,10 +1799,13 @@ all subscripts applied to X are to be taken modulo r. The state xᵢ
|
|
| 1499 |
additionally consists of an integer c (known as the *carry*) whose value
|
| 1500 |
is either 0 or 1.
|
| 1501 |
|
| 1502 |
The state transition is performed as follows:
|
| 1503 |
|
|
|
|
|
|
|
|
|
|
| 1504 |
[*Note 1*: This algorithm corresponds to a modular linear function of
|
| 1505 |
the form TA(xᵢ) = (a ⋅ xᵢ) mod b, where b is of the form mʳ - mˢ + 1
|
| 1506 |
and a = b - (b - 1) / m. — *end note*]
|
| 1507 |
|
| 1508 |
The generation algorithm is given by GA(xᵢ) = y, where y is the value
|
|
@@ -1522,11 +1825,12 @@ template<class UIntType, size_t w, size_t s, size_t r>
|
|
| 1522 |
static constexpr result_type min() { return 0; }
|
| 1523 |
static constexpr result_type max() { return m - 1; }
|
| 1524 |
static constexpr result_type default_seed = 19780503u;
|
| 1525 |
|
| 1526 |
// constructors and seeding functions
|
| 1527 |
-
|
|
|
|
| 1528 |
template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
|
| 1529 |
void seed(result_type value = default_seed);
|
| 1530 |
template<class Sseq> void seed(Sseq& q);
|
| 1531 |
|
| 1532 |
// generating functions
|
|
@@ -1540,16 +1844,15 @@ The following relations shall hold: `0u < s`, `s < r`, `0 < w`, and
|
|
| 1540 |
|
| 1541 |
The textual representation consists of the values of Xᵢ₋ᵣ, …, Xᵢ₋₁, in
|
| 1542 |
that order, followed by c.
|
| 1543 |
|
| 1544 |
``` cpp
|
| 1545 |
-
explicit subtract_with_carry_engine(result_type value
|
| 1546 |
```
|
| 1547 |
|
| 1548 |
-
*Effects:*
|
| 1549 |
-
|
| 1550 |
-
0, sets c to 1; otherwise sets c to 0.
|
| 1551 |
|
| 1552 |
To set the values Xₖ, first construct `e`, a
|
| 1553 |
`linear_congruential_engine` object, as if by the following definition:
|
| 1554 |
|
| 1555 |
``` cpp
|
|
@@ -1565,45 +1868,44 @@ $\left( \sum_{j=0}^{n-1} z_j \cdot 2^{32j}\right) \bmod m$.
|
|
| 1565 |
|
| 1566 |
``` cpp
|
| 1567 |
template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
|
| 1568 |
```
|
| 1569 |
|
| 1570 |
-
*Effects:*
|
| 1571 |
-
|
| 1572 |
-
|
| 1573 |
-
sets Xᵢ to
|
| 1574 |
$\left(\sum_{j=0}^{k-1}a_{k(i+r)+j} \cdot 2^{32j} \right) \bmod m$. If
|
| 1575 |
X₋₁ is then 0, sets c to 1; otherwise sets c to 0.
|
| 1576 |
|
| 1577 |
### Random number engine adaptor class templates <a id="rand.adapt">[[rand.adapt]]</a>
|
| 1578 |
|
| 1579 |
#### In general <a id="rand.adapt.general">[[rand.adapt.general]]</a>
|
| 1580 |
|
| 1581 |
-
Each type instantiated from a class template specified in this
|
| 1582 |
-
[[rand.adapt]]
|
| 1583 |
-
adaptor
|
| 1584 |
|
| 1585 |
Except where specified otherwise, the complexity of each function
|
| 1586 |
-
specified in this
|
| 1587 |
|
| 1588 |
-
Except where specified otherwise, no function described in this
|
| 1589 |
-
[[rand.adapt]] throws an exception.
|
| 1590 |
|
| 1591 |
-
Every function described in this
|
| 1592 |
function parameter `q` of type `Sseq&` for a template type parameter
|
| 1593 |
named `Sseq` that is different from type `seed_seq` throws what and when
|
| 1594 |
the invocation of `q.generate` throws.
|
| 1595 |
|
| 1596 |
-
Descriptions are provided in this
|
| 1597 |
-
adaptor operations that are not described in
|
| 1598 |
-
or for operations where there is additional semantic
|
| 1599 |
-
particular, declarations for copy constructors, for copy
|
| 1600 |
-
operators, for streaming operators, and for equality and
|
| 1601 |
-
operators are not shown in the synopses.
|
| 1602 |
|
| 1603 |
-
Each template specified in this
|
| 1604 |
-
more relationships, involving the value(s) of its non-type template
|
| 1605 |
parameter(s), to hold. A program instantiating any of these templates is
|
| 1606 |
ill-formed if any such required relationship fails to hold.
|
| 1607 |
|
| 1608 |
#### Class template `discard_block_engine` <a id="rand.adapt.disc">[[rand.adapt.disc]]</a>
|
| 1609 |
|
|
@@ -1661,11 +1963,11 @@ template<class Engine, size_t p, size_t r>
|
|
| 1661 |
The following relations shall hold: `0 < r` and `r <= p`.
|
| 1662 |
|
| 1663 |
The textual representation consists of the textual representation of `e`
|
| 1664 |
followed by the value of `n`.
|
| 1665 |
|
| 1666 |
-
In addition to its behavior pursuant to
|
| 1667 |
each constructor that is not a copy constructor sets `n` to 0.
|
| 1668 |
|
| 1669 |
#### Class template `independent_bits_engine` <a id="rand.adapt.ibits">[[rand.adapt.ibits]]</a>
|
| 1670 |
|
| 1671 |
An `independent_bits_engine` random number engine adaptor combines
|
|
@@ -1676,10 +1978,17 @@ state eᵢ of its base engine `e`; the size of the state is the size of
|
|
| 1676 |
e’s state.
|
| 1677 |
|
| 1678 |
The transition and generation algorithms are described in terms of the
|
| 1679 |
following integral constants:
|
| 1680 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1681 |
[*Note 1*: The relation w = n₀ w₀ + (n - n₀)(w₀ + 1) always
|
| 1682 |
holds. — *end note*]
|
| 1683 |
|
| 1684 |
The transition algorithm is carried out by invoking `e()` as often as
|
| 1685 |
needed to obtain n₀ values less than y₀ + `e.min()` and n - n₀ values
|
|
@@ -1751,10 +2060,15 @@ additional sequence V of k values also of the type delivered by `e`. The
|
|
| 1751 |
size of the state is the size of e’s state plus k + 1.
|
| 1752 |
|
| 1753 |
The transition algorithm permutes the values produced by e. The state
|
| 1754 |
transition is performed as follows:
|
| 1755 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 1756 |
The generation algorithm yields the last value of `Y` produced while
|
| 1757 |
advancing `e`’s state as described above.
|
| 1758 |
|
| 1759 |
``` cpp
|
| 1760 |
template<class Engine, size_t k>
|
|
@@ -1795,99 +2109,96 @@ template<class Engine, size_t k>
|
|
| 1795 |
The following relation shall hold: `0 < k`.
|
| 1796 |
|
| 1797 |
The textual representation consists of the textual representation of
|
| 1798 |
`e`, followed by the `k` values of V, followed by the value of Y.
|
| 1799 |
|
| 1800 |
-
In addition to its behavior pursuant to
|
| 1801 |
each constructor that is not a copy constructor initializes
|
| 1802 |
`V[0]`, …, `V[k-1]` and Y, in that order, with values returned by
|
| 1803 |
successive invocations of `e()`.
|
| 1804 |
|
| 1805 |
### Engines and engine adaptors with predefined parameters <a id="rand.predef">[[rand.predef]]</a>
|
| 1806 |
|
| 1807 |
``` cpp
|
| 1808 |
using minstd_rand0 =
|
| 1809 |
-
linear_congruential_engine<uint_fast32_t,
|
| 1810 |
```
|
| 1811 |
|
| 1812 |
-
*Required behavior:* The
|
| 1813 |
-
default-constructed object of type `minstd_rand0`
|
| 1814 |
-
|
| 1815 |
|
| 1816 |
``` cpp
|
| 1817 |
using minstd_rand =
|
| 1818 |
-
linear_congruential_engine<uint_fast32_t,
|
| 1819 |
```
|
| 1820 |
|
| 1821 |
-
*Required behavior:* The
|
| 1822 |
-
default-constructed object of type `minstd_rand`
|
| 1823 |
399268537.
|
| 1824 |
|
| 1825 |
``` cpp
|
| 1826 |
using mt19937 =
|
| 1827 |
-
mersenne_twister_engine<uint_fast32_t,
|
| 1828 |
-
|
| 1829 |
```
|
| 1830 |
|
| 1831 |
-
*Required behavior:* The
|
| 1832 |
-
default-constructed object of type `mt19937`
|
| 1833 |
4123659995.
|
| 1834 |
|
| 1835 |
``` cpp
|
| 1836 |
using mt19937_64 =
|
| 1837 |
-
mersenne_twister_engine<uint_fast64_t,
|
| 1838 |
-
|
| 1839 |
-
|
| 1840 |
-
0x71d67fffeda60000,37,
|
| 1841 |
-
0xfff7eee000000000,43,
|
| 1842 |
-
6364136223846793005>;
|
| 1843 |
```
|
| 1844 |
|
| 1845 |
-
*Required behavior:* The
|
| 1846 |
-
default-constructed object of type `mt19937_64`
|
| 1847 |
9981545732273789042.
|
| 1848 |
|
| 1849 |
``` cpp
|
| 1850 |
using ranlux24_base =
|
| 1851 |
subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>;
|
| 1852 |
```
|
| 1853 |
|
| 1854 |
-
*Required behavior:* The
|
| 1855 |
-
default-constructed object of type `ranlux24_base`
|
| 1856 |
-
|
| 1857 |
|
| 1858 |
``` cpp
|
| 1859 |
using ranlux48_base =
|
| 1860 |
subtract_with_carry_engine<uint_fast64_t, 48, 5, 12>;
|
| 1861 |
```
|
| 1862 |
|
| 1863 |
-
*Required behavior:* The
|
| 1864 |
-
default-constructed object of type `ranlux48_base`
|
| 1865 |
-
|
| 1866 |
|
| 1867 |
``` cpp
|
| 1868 |
using ranlux24 = discard_block_engine<ranlux24_base, 223, 23>;
|
| 1869 |
```
|
| 1870 |
|
| 1871 |
-
*Required behavior:* The
|
| 1872 |
-
default-constructed object of type `ranlux24`
|
| 1873 |
9901578.
|
| 1874 |
|
| 1875 |
``` cpp
|
| 1876 |
using ranlux48 = discard_block_engine<ranlux48_base, 389, 11>;
|
| 1877 |
```
|
| 1878 |
|
| 1879 |
-
*Required behavior:* The
|
| 1880 |
-
default-constructed object of type `ranlux48`
|
| 1881 |
249142670248501.
|
| 1882 |
|
| 1883 |
``` cpp
|
| 1884 |
using knuth_b = shuffle_order_engine<minstd_rand0,256>;
|
| 1885 |
```
|
| 1886 |
|
| 1887 |
-
*Required behavior:* The
|
| 1888 |
-
default-constructed object of type `knuth_b`
|
| 1889 |
1112339016.
|
| 1890 |
|
| 1891 |
``` cpp
|
| 1892 |
using default_random_engine = implementation-defined;
|
| 1893 |
```
|
|
@@ -1920,11 +2231,12 @@ public:
|
|
| 1920 |
// generator characteristics
|
| 1921 |
static constexpr result_type min() { return numeric_limits<result_type>::min(); }
|
| 1922 |
static constexpr result_type max() { return numeric_limits<result_type>::max(); }
|
| 1923 |
|
| 1924 |
// constructors
|
| 1925 |
-
|
|
|
|
| 1926 |
|
| 1927 |
// generating functions
|
| 1928 |
result_type operator()();
|
| 1929 |
|
| 1930 |
// property functions
|
|
@@ -1935,16 +2247,15 @@ public:
|
|
| 1935 |
void operator=(const random_device&) = delete;
|
| 1936 |
};
|
| 1937 |
```
|
| 1938 |
|
| 1939 |
``` cpp
|
| 1940 |
-
explicit random_device(const string& token
|
| 1941 |
```
|
| 1942 |
|
| 1943 |
-
*
|
| 1944 |
-
|
| 1945 |
-
parameter are *implementation-defined*. [^3]
|
| 1946 |
|
| 1947 |
*Throws:* A value of an *implementation-defined* type derived from
|
| 1948 |
`exception` if the `random_device` could not be initialized.
|
| 1949 |
|
| 1950 |
``` cpp
|
|
@@ -1958,11 +2269,11 @@ returned by `operator()`, in the range `min()` to log₂( `max()`+1).
|
|
| 1958 |
``` cpp
|
| 1959 |
result_type operator()();
|
| 1960 |
```
|
| 1961 |
|
| 1962 |
*Returns:* A nondeterministic random value, uniformly distributed
|
| 1963 |
-
between `min()` and `max()`
|
| 1964 |
how these values are generated.
|
| 1965 |
|
| 1966 |
*Throws:* A value of an *implementation-defined* type derived from
|
| 1967 |
`exception` if a random number could not be obtained.
|
| 1968 |
|
|
@@ -2003,35 +2314,35 @@ private:
|
|
| 2003 |
|
| 2004 |
``` cpp
|
| 2005 |
seed_seq();
|
| 2006 |
```
|
| 2007 |
|
| 2008 |
-
*
|
| 2009 |
-
its member `v`.
|
| 2010 |
|
| 2011 |
*Throws:* Nothing.
|
| 2012 |
|
| 2013 |
``` cpp
|
| 2014 |
template<class T>
|
| 2015 |
seed_seq(initializer_list<T> il);
|
| 2016 |
```
|
| 2017 |
|
| 2018 |
-
*
|
| 2019 |
|
| 2020 |
*Effects:* Same as `seed_seq(il.begin(), il.end())`.
|
| 2021 |
|
| 2022 |
``` cpp
|
| 2023 |
template<class InputIterator>
|
| 2024 |
seed_seq(InputIterator begin, InputIterator end);
|
| 2025 |
```
|
| 2026 |
|
| 2027 |
-
*
|
| 2028 |
-
iterator (Table [[tab:iterator.input.requirements]]) type. Moreover,
|
| 2029 |
-
`iterator_traits<InputIterator>::value_type` shall denote an integer
|
| 2030 |
type.
|
| 2031 |
|
| 2032 |
-
*
|
|
|
|
|
|
|
|
|
|
| 2033 |
|
| 2034 |
``` cpp
|
| 2035 |
for (InputIterator s = begin; s != end; ++s)
|
| 2036 |
v.push_back((*s) mod 2³²);
|
| 2037 |
```
|
|
@@ -2039,21 +2350,63 @@ for( InputIterator s = begin; s != end; ++s)
|
|
| 2039 |
``` cpp
|
| 2040 |
template<class RandomAccessIterator>
|
| 2041 |
void generate(RandomAccessIterator begin, RandomAccessIterator end);
|
| 2042 |
```
|
| 2043 |
|
| 2044 |
-
*
|
| 2045 |
-
mutable random access iterator ([[random.access.iterators]]). Moreover,
|
| 2046 |
-
`iterator_traits<RandomAccessIterator>::value_type` shall denote an
|
| 2047 |
unsigned integer type capable of accommodating 32-bit quantities.
|
| 2048 |
|
|
|
|
|
|
|
|
|
|
|
|
|
| 2049 |
*Effects:* Does nothing if `begin == end`. Otherwise, with
|
| 2050 |
s = `v.size()` and n = `end` - `begin`, fills the supplied range
|
| 2051 |
[`begin`,`end`) according to the following algorithm in which each
|
| 2052 |
operation is to be carried out modulo 2³², each indexing operator
|
| 2053 |
applied to `begin` is to be taken modulo n, and T(x) is defined as
|
| 2054 |
-
$x \
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 2055 |
|
| 2056 |
*Throws:* What and when `RandomAccessIterator` operations of `begin` and
|
| 2057 |
`end` throw.
|
| 2058 |
|
| 2059 |
``` cpp
|
|
@@ -2068,13 +2421,15 @@ to `param()`.
|
|
| 2068 |
``` cpp
|
| 2069 |
template<class OutputIterator>
|
| 2070 |
void param(OutputIterator dest) const;
|
| 2071 |
```
|
| 2072 |
|
| 2073 |
-
*
|
| 2074 |
-
|
| 2075 |
-
|
|
|
|
|
|
|
| 2076 |
|
| 2077 |
*Effects:* Copies the sequence of prepared 32-bit units to the given
|
| 2078 |
destination, as if by executing the following statement:
|
| 2079 |
|
| 2080 |
``` cpp
|
|
@@ -2083,22 +2438,10 @@ copy(v.begin(), v.end(), dest);
|
|
| 2083 |
|
| 2084 |
*Throws:* What and when `OutputIterator` operations of `dest` throw.
|
| 2085 |
|
| 2086 |
#### Function template `generate_canonical` <a id="rand.util.canonical">[[rand.util.canonical]]</a>
|
| 2087 |
|
| 2088 |
-
Each function instantiated from the template described in this section
|
| 2089 |
-
[[rand.util.canonical]] maps the result of one or more invocations of a
|
| 2090 |
-
supplied uniform random bit generator `g` to one member of the specified
|
| 2091 |
-
`RealType` such that, if the values gᵢ produced by `g` are uniformly
|
| 2092 |
-
distributed, the instantiation’s results tⱼ, 0 ≤ tⱼ < 1, are distributed
|
| 2093 |
-
as uniformly as possible as specified below.
|
| 2094 |
-
|
| 2095 |
-
[*Note 1*: Obtaining a value in this way can be a useful step in the
|
| 2096 |
-
process of transforming a value generated by a uniform random bit
|
| 2097 |
-
generator into a value that can be delivered by a random number
|
| 2098 |
-
distribution. — *end note*]
|
| 2099 |
-
|
| 2100 |
``` cpp
|
| 2101 |
template<class RealType, size_t bits, class URBG>
|
| 2102 |
RealType generate_canonical(URBG& g);
|
| 2103 |
```
|
| 2104 |
|
|
@@ -2111,54 +2454,62 @@ respectively. Calculates a quantity
|
|
| 2111 |
$$S = \sum_{i=0}^{k-1} (g_i - \texttt{g.min()})
|
| 2112 |
\cdot R^i$$ using arithmetic of type `RealType`.
|
| 2113 |
|
| 2114 |
*Returns:* S / Rᵏ.
|
| 2115 |
|
|
|
|
|
|
|
| 2116 |
*Throws:* What and when `g` throws.
|
| 2117 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 2118 |
### Random number distribution class templates <a id="rand.dist">[[rand.dist]]</a>
|
| 2119 |
|
| 2120 |
#### In general <a id="rand.dist.general">[[rand.dist.general]]</a>
|
| 2121 |
|
| 2122 |
-
Each type instantiated from a class template specified in this
|
| 2123 |
-
[[rand.dist]]
|
| 2124 |
-
distribution
|
| 2125 |
|
| 2126 |
-
Descriptions are provided in this
|
| 2127 |
distribution operations that are not described in [[rand.req.dist]] or
|
| 2128 |
for operations where there is additional semantic information. In
|
| 2129 |
particular, declarations for copy constructors, for copy assignment
|
| 2130 |
operators, for streaming operators, and for equality and inequality
|
| 2131 |
operators are not shown in the synopses.
|
| 2132 |
|
| 2133 |
The algorithms for producing each of the specified distributions are
|
| 2134 |
*implementation-defined*.
|
| 2135 |
|
| 2136 |
The value of each probability density function p(z) and of each discrete
|
| 2137 |
-
probability function P(zᵢ) specified in this
|
| 2138 |
outside its stated domain.
|
| 2139 |
|
| 2140 |
#### Uniform distributions <a id="rand.dist.uni">[[rand.dist.uni]]</a>
|
| 2141 |
|
| 2142 |
##### Class template `uniform_int_distribution` <a id="rand.dist.uni.int">[[rand.dist.uni.int]]</a>
|
| 2143 |
|
| 2144 |
A `uniform_int_distribution` random number distribution produces random
|
| 2145 |
integers i, a ≤ i ≤ b, distributed according to the constant discrete
|
| 2146 |
-
probability function $$
|
| 2147 |
-
P(i\,|\,a,b) = 1 / (b - a + 1)
|
| 2148 |
-
\; \mbox{.}$$
|
| 2149 |
|
| 2150 |
``` cpp
|
| 2151 |
template<class IntType = int>
|
| 2152 |
class uniform_int_distribution {
|
| 2153 |
public:
|
| 2154 |
// types
|
| 2155 |
using result_type = IntType;
|
| 2156 |
using param_type = unspecified;
|
| 2157 |
|
| 2158 |
// constructors and reset functions
|
| 2159 |
-
|
|
|
|
| 2160 |
explicit uniform_int_distribution(const param_type& parm);
|
| 2161 |
void reset();
|
| 2162 |
|
| 2163 |
// generating functions
|
| 2164 |
template<class URBG>
|
|
@@ -2175,17 +2526,17 @@ template<class IntType = int>
|
|
| 2175 |
result_type max() const;
|
| 2176 |
};
|
| 2177 |
```
|
| 2178 |
|
| 2179 |
``` cpp
|
| 2180 |
-
explicit uniform_int_distribution(IntType a
|
| 2181 |
```
|
| 2182 |
|
| 2183 |
-
*
|
| 2184 |
|
| 2185 |
-
*
|
| 2186 |
-
|
| 2187 |
|
| 2188 |
``` cpp
|
| 2189 |
result_type a() const;
|
| 2190 |
```
|
| 2191 |
|
|
@@ -2201,13 +2552,11 @@ constructed.
|
|
| 2201 |
|
| 2202 |
##### Class template `uniform_real_distribution` <a id="rand.dist.uni.real">[[rand.dist.uni.real]]</a>
|
| 2203 |
|
| 2204 |
A `uniform_real_distribution` random number distribution produces random
|
| 2205 |
numbers x, a ≤ x < b, distributed according to the constant probability
|
| 2206 |
-
density function $$
|
| 2207 |
-
p(x\,|\,a,b) = 1 / (b - a)
|
| 2208 |
-
\; \mbox{.}$$
|
| 2209 |
|
| 2210 |
[*Note 1*: This implies that p(x | a,b) is undefined when
|
| 2211 |
`a == b`. — *end note*]
|
| 2212 |
|
| 2213 |
``` cpp
|
|
@@ -2217,11 +2566,12 @@ template<class RealType = double>
|
|
| 2217 |
// types
|
| 2218 |
using result_type = RealType;
|
| 2219 |
using param_type = unspecified;
|
| 2220 |
|
| 2221 |
// constructors and reset functions
|
| 2222 |
-
|
|
|
|
| 2223 |
explicit uniform_real_distribution(const param_type& parm);
|
| 2224 |
void reset();
|
| 2225 |
|
| 2226 |
// generating functions
|
| 2227 |
template<class URBG>
|
|
@@ -2238,17 +2588,18 @@ template<class RealType = double>
|
|
| 2238 |
result_type max() const;
|
| 2239 |
};
|
| 2240 |
```
|
| 2241 |
|
| 2242 |
``` cpp
|
| 2243 |
-
explicit uniform_real_distribution(RealType a
|
| 2244 |
```
|
| 2245 |
|
| 2246 |
-
*
|
|
|
|
| 2247 |
|
| 2248 |
-
*
|
| 2249 |
-
|
| 2250 |
|
| 2251 |
``` cpp
|
| 2252 |
result_type a() const;
|
| 2253 |
```
|
| 2254 |
|
|
@@ -2265,27 +2616,26 @@ constructed.
|
|
| 2265 |
#### Bernoulli distributions <a id="rand.dist.bern">[[rand.dist.bern]]</a>
|
| 2266 |
|
| 2267 |
##### Class `bernoulli_distribution` <a id="rand.dist.bern.bernoulli">[[rand.dist.bern.bernoulli]]</a>
|
| 2268 |
|
| 2269 |
A `bernoulli_distribution` random number distribution produces `bool`
|
| 2270 |
-
values b distributed according to the discrete probability function
|
| 2271 |
-
|
| 2272 |
-
|
| 2273 |
-
|
| 2274 |
-
|
| 2275 |
-
\end{array}\right.
|
| 2276 |
-
\; \mbox{.}$$
|
| 2277 |
|
| 2278 |
``` cpp
|
| 2279 |
class bernoulli_distribution {
|
| 2280 |
public:
|
| 2281 |
// types
|
| 2282 |
using result_type = bool;
|
| 2283 |
using param_type = unspecified;
|
| 2284 |
|
| 2285 |
// constructors and reset functions
|
| 2286 |
-
|
|
|
|
| 2287 |
explicit bernoulli_distribution(const param_type& parm);
|
| 2288 |
void reset();
|
| 2289 |
|
| 2290 |
// generating functions
|
| 2291 |
template<class URBG>
|
|
@@ -2301,17 +2651,16 @@ public:
|
|
| 2301 |
result_type max() const;
|
| 2302 |
};
|
| 2303 |
```
|
| 2304 |
|
| 2305 |
``` cpp
|
| 2306 |
-
explicit bernoulli_distribution(double p
|
| 2307 |
```
|
| 2308 |
|
| 2309 |
-
*
|
| 2310 |
|
| 2311 |
-
*
|
| 2312 |
-
to the parameter of the distribution.
|
| 2313 |
|
| 2314 |
``` cpp
|
| 2315 |
double p() const;
|
| 2316 |
```
|
| 2317 |
|
|
@@ -2320,25 +2669,23 @@ constructed.
|
|
| 2320 |
|
| 2321 |
##### Class template `binomial_distribution` <a id="rand.dist.bern.bin">[[rand.dist.bern.bin]]</a>
|
| 2322 |
|
| 2323 |
A `binomial_distribution` random number distribution produces integer
|
| 2324 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2325 |
-
$$
|
| 2326 |
-
P(i\,|\,t,p)
|
| 2327 |
-
= \binom{t}{i} \cdot p^i \cdot (1-p)^{t-i}
|
| 2328 |
-
\; \mbox{.}$$
|
| 2329 |
|
| 2330 |
``` cpp
|
| 2331 |
template<class IntType = int>
|
| 2332 |
class binomial_distribution {
|
| 2333 |
public:
|
| 2334 |
// types
|
| 2335 |
using result_type = IntType;
|
| 2336 |
using param_type = unspecified;
|
| 2337 |
|
| 2338 |
// constructors and reset functions
|
| 2339 |
-
|
|
|
|
| 2340 |
explicit binomial_distribution(const param_type& parm);
|
| 2341 |
void reset();
|
| 2342 |
|
| 2343 |
// generating functions
|
| 2344 |
template<class URBG>
|
|
@@ -2355,17 +2702,17 @@ template<class IntType = int>
|
|
| 2355 |
result_type max() const;
|
| 2356 |
};
|
| 2357 |
```
|
| 2358 |
|
| 2359 |
``` cpp
|
| 2360 |
-
explicit binomial_distribution(IntType t
|
| 2361 |
```
|
| 2362 |
|
| 2363 |
-
*
|
| 2364 |
|
| 2365 |
-
*
|
| 2366 |
-
|
| 2367 |
|
| 2368 |
``` cpp
|
| 2369 |
IntType t() const;
|
| 2370 |
```
|
| 2371 |
|
|
@@ -2381,25 +2728,23 @@ constructed.
|
|
| 2381 |
|
| 2382 |
##### Class template `geometric_distribution` <a id="rand.dist.bern.geo">[[rand.dist.bern.geo]]</a>
|
| 2383 |
|
| 2384 |
A `geometric_distribution` random number distribution produces integer
|
| 2385 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2386 |
-
$$
|
| 2387 |
-
P(i\,|\,p)
|
| 2388 |
-
= p \cdot (1-p)^{i}
|
| 2389 |
-
\; \mbox{.}$$
|
| 2390 |
|
| 2391 |
``` cpp
|
| 2392 |
template<class IntType = int>
|
| 2393 |
class geometric_distribution {
|
| 2394 |
public:
|
| 2395 |
// types
|
| 2396 |
using result_type = IntType;
|
| 2397 |
using param_type = unspecified;
|
| 2398 |
|
| 2399 |
// constructors and reset functions
|
| 2400 |
-
|
|
|
|
| 2401 |
explicit geometric_distribution(const param_type& parm);
|
| 2402 |
void reset();
|
| 2403 |
|
| 2404 |
// generating functions
|
| 2405 |
template<class URBG>
|
|
@@ -2415,17 +2760,16 @@ template<class IntType = int>
|
|
| 2415 |
result_type max() const;
|
| 2416 |
};
|
| 2417 |
```
|
| 2418 |
|
| 2419 |
``` cpp
|
| 2420 |
-
explicit geometric_distribution(double p
|
| 2421 |
```
|
| 2422 |
|
| 2423 |
-
*
|
| 2424 |
|
| 2425 |
-
*
|
| 2426 |
-
to the parameter of the distribution.
|
| 2427 |
|
| 2428 |
``` cpp
|
| 2429 |
double p() const;
|
| 2430 |
```
|
| 2431 |
|
|
@@ -2434,14 +2778,12 @@ constructed.
|
|
| 2434 |
|
| 2435 |
##### Class template `negative_binomial_distribution` <a id="rand.dist.bern.negbin">[[rand.dist.bern.negbin]]</a>
|
| 2436 |
|
| 2437 |
A `negative_binomial_distribution` random number distribution produces
|
| 2438 |
random integers i ≥ 0 distributed according to the discrete probability
|
| 2439 |
-
function
|
| 2440 |
-
|
| 2441 |
-
= \binom{k+i-1}{i} \cdot p^k \cdot (1-p)^i
|
| 2442 |
-
\; \mbox{.}$$
|
| 2443 |
|
| 2444 |
[*Note 1*: This implies that P(i | k,p) is undefined when
|
| 2445 |
`p == 1`. — *end note*]
|
| 2446 |
|
| 2447 |
``` cpp
|
|
@@ -2451,11 +2793,12 @@ template<class IntType = int>
|
|
| 2451 |
// types
|
| 2452 |
using result_type = IntType;
|
| 2453 |
using param_type = unspecified;
|
| 2454 |
|
| 2455 |
// constructor and reset functions
|
| 2456 |
-
|
|
|
|
| 2457 |
explicit negative_binomial_distribution(const param_type& parm);
|
| 2458 |
void reset();
|
| 2459 |
|
| 2460 |
// generating functions
|
| 2461 |
template<class URBG>
|
|
@@ -2472,17 +2815,17 @@ template<class IntType = int>
|
|
| 2472 |
result_type max() const;
|
| 2473 |
};
|
| 2474 |
```
|
| 2475 |
|
| 2476 |
``` cpp
|
| 2477 |
-
explicit negative_binomial_distribution(IntType k
|
| 2478 |
```
|
| 2479 |
|
| 2480 |
-
*
|
| 2481 |
|
| 2482 |
-
*
|
| 2483 |
-
|
| 2484 |
|
| 2485 |
``` cpp
|
| 2486 |
IntType k() const;
|
| 2487 |
```
|
| 2488 |
|
|
@@ -2500,16 +2843,12 @@ constructed.
|
|
| 2500 |
|
| 2501 |
##### Class template `poisson_distribution` <a id="rand.dist.pois.poisson">[[rand.dist.pois.poisson]]</a>
|
| 2502 |
|
| 2503 |
A `poisson_distribution` random number distribution produces integer
|
| 2504 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2505 |
-
$$
|
| 2506 |
-
|
| 2507 |
-
= \frac{ e^{-\mu} \mu^{i} }
|
| 2508 |
-
{ i\,! }
|
| 2509 |
-
\; \mbox{.}$$ The distribution parameter μ is also known as this
|
| 2510 |
-
distribution’s *mean* .
|
| 2511 |
|
| 2512 |
``` cpp
|
| 2513 |
template<class IntType = int>
|
| 2514 |
class poisson_distribution
|
| 2515 |
{
|
|
@@ -2517,11 +2856,12 @@ template<class IntType = int>
|
|
| 2517 |
// types
|
| 2518 |
using result_type = IntType;
|
| 2519 |
using param_type = unspecified;
|
| 2520 |
|
| 2521 |
// constructors and reset functions
|
| 2522 |
-
|
|
|
|
| 2523 |
explicit poisson_distribution(const param_type& parm);
|
| 2524 |
void reset();
|
| 2525 |
|
| 2526 |
// generating functions
|
| 2527 |
template<class URBG>
|
|
@@ -2537,17 +2877,16 @@ template<class IntType = int>
|
|
| 2537 |
result_type max() const;
|
| 2538 |
};
|
| 2539 |
```
|
| 2540 |
|
| 2541 |
``` cpp
|
| 2542 |
-
explicit poisson_distribution(double mean
|
| 2543 |
```
|
| 2544 |
|
| 2545 |
-
*
|
| 2546 |
|
| 2547 |
-
*
|
| 2548 |
-
corresponds to the parameter of the distribution.
|
| 2549 |
|
| 2550 |
``` cpp
|
| 2551 |
double mean() const;
|
| 2552 |
```
|
| 2553 |
|
|
@@ -2556,25 +2895,23 @@ constructed.
|
|
| 2556 |
|
| 2557 |
##### Class template `exponential_distribution` <a id="rand.dist.pois.exp">[[rand.dist.pois.exp]]</a>
|
| 2558 |
|
| 2559 |
An `exponential_distribution` random number distribution produces random
|
| 2560 |
numbers x > 0 distributed according to the probability density function
|
| 2561 |
-
$$
|
| 2562 |
-
p(x\,|\,\lambda)
|
| 2563 |
-
= \lambda e^{-\lambda x}
|
| 2564 |
-
\; \mbox{.}$$
|
| 2565 |
|
| 2566 |
``` cpp
|
| 2567 |
template<class RealType = double>
|
| 2568 |
class exponential_distribution {
|
| 2569 |
public:
|
| 2570 |
// types
|
| 2571 |
using result_type = RealType;
|
| 2572 |
using param_type = unspecified;
|
| 2573 |
|
| 2574 |
// constructors and reset functions
|
| 2575 |
-
|
|
|
|
| 2576 |
explicit exponential_distribution(const param_type& parm);
|
| 2577 |
void reset();
|
| 2578 |
|
| 2579 |
// generating functions
|
| 2580 |
template<class URBG>
|
|
@@ -2590,17 +2927,16 @@ template<class RealType = double>
|
|
| 2590 |
result_type max() const;
|
| 2591 |
};
|
| 2592 |
```
|
| 2593 |
|
| 2594 |
``` cpp
|
| 2595 |
-
explicit exponential_distribution(RealType lambda
|
| 2596 |
```
|
| 2597 |
|
| 2598 |
-
*
|
| 2599 |
|
| 2600 |
-
*
|
| 2601 |
-
corresponds to the parameter of the distribution.
|
| 2602 |
|
| 2603 |
``` cpp
|
| 2604 |
RealType lambda() const;
|
| 2605 |
```
|
| 2606 |
|
|
@@ -2609,26 +2945,25 @@ constructed.
|
|
| 2609 |
|
| 2610 |
##### Class template `gamma_distribution` <a id="rand.dist.pois.gamma">[[rand.dist.pois.gamma]]</a>
|
| 2611 |
|
| 2612 |
A `gamma_distribution` random number distribution produces random
|
| 2613 |
numbers x > 0 distributed according to the probability density function
|
| 2614 |
-
$$
|
| 2615 |
-
|
| 2616 |
-
|
| 2617 |
-
\, \cdot \, x^{\, \alpha-1}
|
| 2618 |
-
\; \mbox{.}$$
|
| 2619 |
|
| 2620 |
``` cpp
|
| 2621 |
template<class RealType = double>
|
| 2622 |
class gamma_distribution {
|
| 2623 |
public:
|
| 2624 |
// types
|
| 2625 |
using result_type = RealType;
|
| 2626 |
using param_type = unspecified;
|
| 2627 |
|
| 2628 |
// constructors and reset functions
|
| 2629 |
-
|
|
|
|
| 2630 |
explicit gamma_distribution(const param_type& parm);
|
| 2631 |
void reset();
|
| 2632 |
|
| 2633 |
// generating functions
|
| 2634 |
template<class URBG>
|
|
@@ -2645,17 +2980,17 @@ template<class RealType = double>
|
|
| 2645 |
result_type max() const;
|
| 2646 |
};
|
| 2647 |
```
|
| 2648 |
|
| 2649 |
``` cpp
|
| 2650 |
-
explicit gamma_distribution(RealType alpha
|
| 2651 |
```
|
| 2652 |
|
| 2653 |
-
*
|
| 2654 |
|
| 2655 |
-
*
|
| 2656 |
-
|
| 2657 |
|
| 2658 |
``` cpp
|
| 2659 |
RealType alpha() const;
|
| 2660 |
```
|
| 2661 |
|
|
@@ -2671,27 +3006,26 @@ constructed.
|
|
| 2671 |
|
| 2672 |
##### Class template `weibull_distribution` <a id="rand.dist.pois.weibull">[[rand.dist.pois.weibull]]</a>
|
| 2673 |
|
| 2674 |
A `weibull_distribution` random number distribution produces random
|
| 2675 |
numbers x ≥ 0 distributed according to the probability density function
|
| 2676 |
-
$$
|
| 2677 |
-
p(x\,|\,a,b)
|
| 2678 |
-
= \frac{a}{b}
|
| 2679 |
\cdot \left(\frac{x}{b}\right)^{a-1}
|
| 2680 |
\cdot \, \exp\left( -\left(\frac{x}{b}\right)^a\right)
|
| 2681 |
-
\
|
| 2682 |
|
| 2683 |
``` cpp
|
| 2684 |
template<class RealType = double>
|
| 2685 |
class weibull_distribution {
|
| 2686 |
public:
|
| 2687 |
// types
|
| 2688 |
using result_type = RealType;
|
| 2689 |
using param_type = unspecified;
|
| 2690 |
|
| 2691 |
// constructor and reset functions
|
| 2692 |
-
|
|
|
|
| 2693 |
explicit weibull_distribution(const param_type& parm);
|
| 2694 |
void reset();
|
| 2695 |
|
| 2696 |
// generating functions
|
| 2697 |
template<class URBG>
|
|
@@ -2708,17 +3042,17 @@ template<class RealType = double>
|
|
| 2708 |
result_type max() const;
|
| 2709 |
};
|
| 2710 |
```
|
| 2711 |
|
| 2712 |
``` cpp
|
| 2713 |
-
explicit weibull_distribution(RealType a
|
| 2714 |
```
|
| 2715 |
|
| 2716 |
-
*
|
| 2717 |
|
| 2718 |
-
*
|
| 2719 |
-
|
| 2720 |
|
| 2721 |
``` cpp
|
| 2722 |
RealType a() const;
|
| 2723 |
```
|
| 2724 |
|
|
@@ -2734,28 +3068,25 @@ constructed.
|
|
| 2734 |
|
| 2735 |
##### Class template `extreme_value_distribution` <a id="rand.dist.pois.extreme">[[rand.dist.pois.extreme]]</a>
|
| 2736 |
|
| 2737 |
An `extreme_value_distribution` random number distribution produces
|
| 2738 |
random numbers x distributed according to the probability density
|
| 2739 |
-
function[^6] $$
|
| 2740 |
-
|
| 2741 |
-
|
| 2742 |
-
\cdot \exp\left( \frac{a-x}{b}
|
| 2743 |
-
\,-\, \exp\left(\frac{a-x}{b}\right)
|
| 2744 |
-
\right)
|
| 2745 |
-
\; \mbox{.}$$
|
| 2746 |
|
| 2747 |
``` cpp
|
| 2748 |
template<class RealType = double>
|
| 2749 |
class extreme_value_distribution {
|
| 2750 |
public:
|
| 2751 |
// types
|
| 2752 |
using result_type = RealType;
|
| 2753 |
using param_type = unspecified;
|
| 2754 |
|
| 2755 |
// constructor and reset functions
|
| 2756 |
-
|
|
|
|
| 2757 |
explicit extreme_value_distribution(const param_type& parm);
|
| 2758 |
void reset();
|
| 2759 |
|
| 2760 |
// generating functions
|
| 2761 |
template<class URBG>
|
|
@@ -2772,17 +3103,17 @@ template<class RealType = double>
|
|
| 2772 |
result_type max() const;
|
| 2773 |
};
|
| 2774 |
```
|
| 2775 |
|
| 2776 |
``` cpp
|
| 2777 |
-
explicit extreme_value_distribution(RealType a
|
| 2778 |
```
|
| 2779 |
|
| 2780 |
-
*
|
| 2781 |
|
| 2782 |
-
*
|
| 2783 |
-
|
| 2784 |
|
| 2785 |
``` cpp
|
| 2786 |
RealType a() const;
|
| 2787 |
```
|
| 2788 |
|
|
@@ -2808,11 +3139,11 @@ numbers x distributed according to the probability density function $$%
|
|
| 2808 |
% e^{-(x-\mu)^2 / (2\sigma^2)}
|
| 2809 |
\exp{\left(- \, \frac{(x - \mu)^2}
|
| 2810 |
{2 \sigma^2}
|
| 2811 |
\right)
|
| 2812 |
}
|
| 2813 |
-
|
| 2814 |
distribution’s *mean* and *standard deviation* .
|
| 2815 |
|
| 2816 |
``` cpp
|
| 2817 |
template<class RealType = double>
|
| 2818 |
class normal_distribution {
|
|
@@ -2820,11 +3151,12 @@ template<class RealType = double>
|
|
| 2820 |
// types
|
| 2821 |
using result_type = RealType;
|
| 2822 |
using param_type = unspecified;
|
| 2823 |
|
| 2824 |
// constructors and reset functions
|
| 2825 |
-
|
|
|
|
| 2826 |
explicit normal_distribution(const param_type& parm);
|
| 2827 |
void reset();
|
| 2828 |
|
| 2829 |
// generating functions
|
| 2830 |
template<class URBG>
|
|
@@ -2841,17 +3173,17 @@ template<class RealType = double>
|
|
| 2841 |
result_type max() const;
|
| 2842 |
};
|
| 2843 |
```
|
| 2844 |
|
| 2845 |
``` cpp
|
| 2846 |
-
explicit normal_distribution(RealType mean
|
| 2847 |
```
|
| 2848 |
|
| 2849 |
-
*
|
| 2850 |
|
| 2851 |
-
*
|
| 2852 |
-
|
| 2853 |
|
| 2854 |
``` cpp
|
| 2855 |
RealType mean() const;
|
| 2856 |
```
|
| 2857 |
|
|
@@ -2867,31 +3199,25 @@ constructed.
|
|
| 2867 |
|
| 2868 |
##### Class template `lognormal_distribution` <a id="rand.dist.norm.lognormal">[[rand.dist.norm.lognormal]]</a>
|
| 2869 |
|
| 2870 |
A `lognormal_distribution` random number distribution produces random
|
| 2871 |
numbers x > 0 distributed according to the probability density function
|
| 2872 |
-
$$
|
| 2873 |
-
|
| 2874 |
-
|
| 2875 |
-
{s x \sqrt{2 \pi}}
|
| 2876 |
-
\cdot
|
| 2877 |
-
\exp{\left(- \, \frac{(\ln{x} - m)^2}
|
| 2878 |
-
{2 s^2}
|
| 2879 |
-
\right)
|
| 2880 |
-
}
|
| 2881 |
-
\; \mbox{.}$$
|
| 2882 |
|
| 2883 |
``` cpp
|
| 2884 |
template<class RealType = double>
|
| 2885 |
class lognormal_distribution {
|
| 2886 |
public:
|
| 2887 |
// types
|
| 2888 |
using result_type = RealType;
|
| 2889 |
using param_type = unspecified;
|
| 2890 |
|
| 2891 |
// constructor and reset functions
|
| 2892 |
-
|
|
|
|
| 2893 |
explicit lognormal_distribution(const param_type& parm);
|
| 2894 |
void reset();
|
| 2895 |
|
| 2896 |
// generating functions
|
| 2897 |
template<class URBG>
|
|
@@ -2908,17 +3234,17 @@ template<class RealType = double>
|
|
| 2908 |
result_type max() const;
|
| 2909 |
};
|
| 2910 |
```
|
| 2911 |
|
| 2912 |
``` cpp
|
| 2913 |
-
explicit lognormal_distribution(RealType m
|
| 2914 |
```
|
| 2915 |
|
| 2916 |
-
*
|
| 2917 |
|
| 2918 |
-
*
|
| 2919 |
-
|
| 2920 |
|
| 2921 |
``` cpp
|
| 2922 |
RealType m() const;
|
| 2923 |
```
|
| 2924 |
|
|
@@ -2934,26 +3260,23 @@ constructed.
|
|
| 2934 |
|
| 2935 |
##### Class template `chi_squared_distribution` <a id="rand.dist.norm.chisq">[[rand.dist.norm.chisq]]</a>
|
| 2936 |
|
| 2937 |
A `chi_squared_distribution` random number distribution produces random
|
| 2938 |
numbers x > 0 distributed according to the probability density function
|
| 2939 |
-
$$
|
| 2940 |
-
p(x\,|\,n)
|
| 2941 |
-
= \frac{ x^{(n/2)-1} \cdot e^{-x/2}}
|
| 2942 |
-
{\Gamma(n/2) \cdot 2^{n/2}}
|
| 2943 |
-
\; \mbox{.}$$
|
| 2944 |
|
| 2945 |
``` cpp
|
| 2946 |
template<class RealType = double>
|
| 2947 |
class chi_squared_distribution {
|
| 2948 |
public:
|
| 2949 |
// types
|
| 2950 |
using result_type = RealType;
|
| 2951 |
using param_type = unspecified;
|
| 2952 |
|
| 2953 |
// constructor and reset functions
|
| 2954 |
-
|
|
|
|
| 2955 |
explicit chi_squared_distribution(const param_type& parm);
|
| 2956 |
void reset();
|
| 2957 |
|
| 2958 |
// generating functions
|
| 2959 |
template<class URBG>
|
|
@@ -2969,17 +3292,16 @@ template<class RealType = double>
|
|
| 2969 |
result_type max() const;
|
| 2970 |
};
|
| 2971 |
```
|
| 2972 |
|
| 2973 |
``` cpp
|
| 2974 |
-
explicit chi_squared_distribution(RealType n
|
| 2975 |
```
|
| 2976 |
|
| 2977 |
-
*
|
| 2978 |
|
| 2979 |
-
*
|
| 2980 |
-
corresponds to the parameter of the distribution.
|
| 2981 |
|
| 2982 |
``` cpp
|
| 2983 |
RealType n() const;
|
| 2984 |
```
|
| 2985 |
|
|
@@ -2987,25 +3309,24 @@ RealType n() const;
|
|
| 2987 |
constructed.
|
| 2988 |
|
| 2989 |
##### Class template `cauchy_distribution` <a id="rand.dist.norm.cauchy">[[rand.dist.norm.cauchy]]</a>
|
| 2990 |
|
| 2991 |
A `cauchy_distribution` random number distribution produces random
|
| 2992 |
-
numbers x distributed according to the probability density function
|
| 2993 |
-
|
| 2994 |
-
= \left( \pi b \left( 1 + \left( \frac{x-a}{b} \right)^2 \;\right)\right)^{-1}
|
| 2995 |
-
\; \mbox{.}$$
|
| 2996 |
|
| 2997 |
``` cpp
|
| 2998 |
template<class RealType = double>
|
| 2999 |
class cauchy_distribution {
|
| 3000 |
public:
|
| 3001 |
// types
|
| 3002 |
using result_type = RealType;
|
| 3003 |
using param_type = unspecified;
|
| 3004 |
|
| 3005 |
// constructor and reset functions
|
| 3006 |
-
|
|
|
|
| 3007 |
explicit cauchy_distribution(const param_type& parm);
|
| 3008 |
void reset();
|
| 3009 |
|
| 3010 |
// generating functions
|
| 3011 |
template<class URBG>
|
|
@@ -3022,17 +3343,17 @@ template<class RealType = double>
|
|
| 3022 |
result_type max() const;
|
| 3023 |
};
|
| 3024 |
```
|
| 3025 |
|
| 3026 |
``` cpp
|
| 3027 |
-
explicit cauchy_distribution(RealType a
|
| 3028 |
```
|
| 3029 |
|
| 3030 |
-
*
|
| 3031 |
|
| 3032 |
-
*
|
| 3033 |
-
|
| 3034 |
|
| 3035 |
``` cpp
|
| 3036 |
RealType a() const;
|
| 3037 |
```
|
| 3038 |
|
|
@@ -3048,32 +3369,27 @@ constructed.
|
|
| 3048 |
|
| 3049 |
##### Class template `fisher_f_distribution` <a id="rand.dist.norm.f">[[rand.dist.norm.f]]</a>
|
| 3050 |
|
| 3051 |
A `fisher_f_distribution` random number distribution produces random
|
| 3052 |
numbers x ≥ 0 distributed according to the probability density function
|
| 3053 |
-
$$
|
| 3054 |
-
|
| 3055 |
-
|
| 3056 |
-
|
| 3057 |
-
|
| 3058 |
-
\left(\frac{m}{n}\right)^{m/2}
|
| 3059 |
-
\cdot
|
| 3060 |
-
x^{(m/2)-1}
|
| 3061 |
-
\cdot
|
| 3062 |
-
{\left( 1 + \frac{m x}{n} \right)}^{-(m+n)/2}
|
| 3063 |
-
\; \mbox{.}$$
|
| 3064 |
|
| 3065 |
``` cpp
|
| 3066 |
template<class RealType = double>
|
| 3067 |
class fisher_f_distribution {
|
| 3068 |
public:
|
| 3069 |
// types
|
| 3070 |
using result_type = RealType;
|
| 3071 |
using param_type = unspecified;
|
| 3072 |
|
| 3073 |
// constructor and reset functions
|
| 3074 |
-
|
|
|
|
| 3075 |
explicit fisher_f_distribution(const param_type& parm);
|
| 3076 |
void reset();
|
| 3077 |
|
| 3078 |
// generating functions
|
| 3079 |
template<class URBG>
|
|
@@ -3090,17 +3406,17 @@ template<class RealType = double>
|
|
| 3090 |
result_type max() const;
|
| 3091 |
};
|
| 3092 |
```
|
| 3093 |
|
| 3094 |
``` cpp
|
| 3095 |
-
explicit fisher_f_distribution(RealType m
|
| 3096 |
```
|
| 3097 |
|
| 3098 |
-
*
|
| 3099 |
|
| 3100 |
-
*
|
| 3101 |
-
|
| 3102 |
|
| 3103 |
``` cpp
|
| 3104 |
RealType m() const;
|
| 3105 |
```
|
| 3106 |
|
|
@@ -3115,29 +3431,27 @@ RealType n() const;
|
|
| 3115 |
constructed.
|
| 3116 |
|
| 3117 |
##### Class template `student_t_distribution` <a id="rand.dist.norm.t">[[rand.dist.norm.t]]</a>
|
| 3118 |
|
| 3119 |
A `student_t_distribution` random number distribution produces random
|
| 3120 |
-
numbers x distributed according to the probability density function
|
| 3121 |
-
|
| 3122 |
-
|
| 3123 |
-
{\sqrt{n \pi}}
|
| 3124 |
-
\cdot \frac{\Gamma\big((n+1)/2\big)}
|
| 3125 |
-
{\Gamma(n/2)}
|
| 3126 |
\cdot \left(1 + \frac{x^2}{n} \right)^{-(n+1)/2}
|
| 3127 |
-
\
|
| 3128 |
|
| 3129 |
``` cpp
|
| 3130 |
template<class RealType = double>
|
| 3131 |
class student_t_distribution {
|
| 3132 |
public:
|
| 3133 |
// types
|
| 3134 |
using result_type = RealType;
|
| 3135 |
using param_type = unspecified;
|
| 3136 |
|
| 3137 |
// constructor and reset functions
|
| 3138 |
-
|
|
|
|
| 3139 |
explicit student_t_distribution(const param_type& parm);
|
| 3140 |
void reset();
|
| 3141 |
|
| 3142 |
// generating functions
|
| 3143 |
template<class URBG>
|
|
@@ -3153,17 +3467,16 @@ template<class RealType = double>
|
|
| 3153 |
result_type max() const;
|
| 3154 |
};
|
| 3155 |
```
|
| 3156 |
|
| 3157 |
``` cpp
|
| 3158 |
-
explicit student_t_distribution(RealType n
|
| 3159 |
```
|
| 3160 |
|
| 3161 |
-
*
|
| 3162 |
|
| 3163 |
-
*
|
| 3164 |
-
to the parameter of the distribution.
|
| 3165 |
|
| 3166 |
``` cpp
|
| 3167 |
RealType n() const;
|
| 3168 |
```
|
| 3169 |
|
|
@@ -3174,20 +3487,17 @@ constructed.
|
|
| 3174 |
|
| 3175 |
##### Class template `discrete_distribution` <a id="rand.dist.samp.discrete">[[rand.dist.samp.discrete]]</a>
|
| 3176 |
|
| 3177 |
A `discrete_distribution` random number distribution produces random
|
| 3178 |
integers i, 0 ≤ i < n, distributed according to the discrete probability
|
| 3179 |
-
function $$
|
| 3180 |
-
P(i\,|\,p_0,\ldots,p_{n-1})
|
| 3181 |
-
= p_i
|
| 3182 |
-
\; \mbox{.}$$
|
| 3183 |
|
| 3184 |
Unless specified otherwise, the distribution parameters are calculated
|
| 3185 |
-
as:
|
| 3186 |
-
|
| 3187 |
-
non-
|
| 3188 |
-
0 < S =
|
| 3189 |
|
| 3190 |
``` cpp
|
| 3191 |
template<class IntType = int>
|
| 3192 |
class discrete_distribution {
|
| 3193 |
public:
|
|
@@ -3233,15 +3543,18 @@ p₀ = 1.
|
|
| 3233 |
``` cpp
|
| 3234 |
template<class InputIterator>
|
| 3235 |
discrete_distribution(InputIterator firstW, InputIterator lastW);
|
| 3236 |
```
|
| 3237 |
|
| 3238 |
-
*
|
| 3239 |
-
|
| 3240 |
-
`
|
| 3241 |
-
|
| 3242 |
-
|
|
|
|
|
|
|
|
|
|
| 3243 |
|
| 3244 |
*Effects:* Constructs a `discrete_distribution` object with
|
| 3245 |
probabilities given by the formula above.
|
| 3246 |
|
| 3247 |
``` cpp
|
|
@@ -3253,22 +3566,22 @@ discrete_distribution(initializer_list<double> wl);
|
|
| 3253 |
``` cpp
|
| 3254 |
template<class UnaryOperation>
|
| 3255 |
discrete_distribution(size_t nw, double xmin, double xmax, UnaryOperation fw);
|
| 3256 |
```
|
| 3257 |
|
| 3258 |
-
*
|
| 3259 |
-
|
| 3260 |
-
|
| 3261 |
-
|
| 3262 |
-
|
| 3263 |
|
| 3264 |
*Effects:* Constructs a `discrete_distribution` object with
|
| 3265 |
probabilities given by the formula above, using the following values: If
|
| 3266 |
`nw` = 0, let w₀ = 1. Otherwise, let wₖ = `fw`(`xmin` + k ⋅ δ + δ / 2)
|
| 3267 |
for k = 0, …, n - 1.
|
| 3268 |
|
| 3269 |
-
*Complexity:* The number of invocations of `fw`
|
| 3270 |
|
| 3271 |
``` cpp
|
| 3272 |
vector<double> probabilities() const;
|
| 3273 |
```
|
| 3274 |
|
|
@@ -3279,27 +3592,21 @@ k = 0, …, n-1.
|
|
| 3279 |
##### Class template `piecewise_constant_distribution` <a id="rand.dist.samp.pconst">[[rand.dist.samp.pconst]]</a>
|
| 3280 |
|
| 3281 |
A `piecewise_constant_distribution` random number distribution produces
|
| 3282 |
random numbers x, b₀ ≤ x < bₙ, uniformly distributed over each
|
| 3283 |
subinterval [ bᵢ, bᵢ₊₁ ) according to the probability density function
|
| 3284 |
-
$$
|
| 3285 |
-
|
| 3286 |
-
= \rho_i
|
| 3287 |
-
\; \mbox{,}
|
| 3288 |
-
\mbox{ for } b_i \le x < b_{i+1}
|
| 3289 |
-
\; \mbox{.}$$
|
| 3290 |
|
| 3291 |
The n + 1 distribution parameters bᵢ, also known as this distribution’s
|
| 3292 |
-
*interval boundaries* , shall satisfy the relation
|
| 3293 |
-
i = 0, …, n-1. Unless specified otherwise, the remaining n
|
| 3294 |
-
parameters are calculated as:
|
| 3295 |
-
|
| 3296 |
-
|
| 3297 |
-
|
| 3298 |
-
|
| 3299 |
-
non-infinity. Moreover, the following relation shall hold:
|
| 3300 |
-
0 < S = w₀ + ⋯ + wₙ₋₁.
|
| 3301 |
|
| 3302 |
``` cpp
|
| 3303 |
template<class RealType = double>
|
| 3304 |
class piecewise_constant_distribution {
|
| 3305 |
public:
|
|
@@ -3347,59 +3654,60 @@ n = 1, ρ₀ = 1, b₀ = 0, and b₁ = 1.
|
|
| 3347 |
template<class InputIteratorB, class InputIteratorW>
|
| 3348 |
piecewise_constant_distribution(InputIteratorB firstB, InputIteratorB lastB,
|
| 3349 |
InputIteratorW firstW);
|
| 3350 |
```
|
| 3351 |
|
| 3352 |
-
*
|
| 3353 |
-
|
| 3354 |
-
|
| 3355 |
-
`iterator_traits<
|
| 3356 |
-
|
| 3357 |
-
|
| 3358 |
-
|
| 3359 |
-
|
| 3360 |
-
|
| 3361 |
-
|
|
|
|
|
|
|
|
|
|
| 3362 |
|
| 3363 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3364 |
parameters as specified above.
|
| 3365 |
|
| 3366 |
``` cpp
|
| 3367 |
template<class UnaryOperation>
|
| 3368 |
piecewise_constant_distribution(initializer_list<RealType> bl, UnaryOperation fw);
|
| 3369 |
```
|
| 3370 |
|
| 3371 |
-
*
|
| 3372 |
-
|
| 3373 |
-
`double`. Moreover, `double` shall be convertible to the type of
|
| 3374 |
-
`UnaryOperation`’s sole parameter.
|
| 3375 |
|
| 3376 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3377 |
parameters taken or calculated from the following values: If
|
| 3378 |
`bl.size()` < 2, let n = 1, w₀ = 1, b₀ = 0, and b₁ = 1. Otherwise, let
|
| 3379 |
[`bl.begin()`, `bl.end()`) form a sequence b₀, …, bₙ, and let
|
| 3380 |
wₖ = `fw`((bₖ₊₁ + bₖ) / 2) for k = 0, …, n - 1.
|
| 3381 |
|
| 3382 |
-
*Complexity:* The number of invocations of `fw`
|
| 3383 |
|
| 3384 |
``` cpp
|
| 3385 |
template<class UnaryOperation>
|
| 3386 |
piecewise_constant_distribution(size_t nw, RealType xmin, RealType xmax, UnaryOperation fw);
|
| 3387 |
```
|
| 3388 |
|
| 3389 |
-
*
|
| 3390 |
-
|
| 3391 |
-
|
| 3392 |
-
|
| 3393 |
-
|
| 3394 |
|
| 3395 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3396 |
parameters taken or calculated from the following values: Let
|
| 3397 |
bₖ = `xmin` + k ⋅ δ for k = 0, …, n, and wₖ = `fw`(bₖ + δ / 2) for
|
| 3398 |
k = 0, …, n - 1.
|
| 3399 |
|
| 3400 |
-
*Complexity:* The number of invocations of `fw`
|
| 3401 |
|
| 3402 |
``` cpp
|
| 3403 |
vector<result_type> intervals() const;
|
| 3404 |
```
|
| 3405 |
|
|
@@ -3417,29 +3725,24 @@ k = 0, …, n-1.
|
|
| 3417 |
|
| 3418 |
##### Class template `piecewise_linear_distribution` <a id="rand.dist.samp.plinear">[[rand.dist.samp.plinear]]</a>
|
| 3419 |
|
| 3420 |
A `piecewise_linear_distribution` random number distribution produces
|
| 3421 |
random numbers x, b₀ ≤ x < bₙ, distributed over each subinterval
|
| 3422 |
-
[
|
| 3423 |
-
|
| 3424 |
-
|
| 3425 |
+ \rho_{i+1} \cdot {\frac{x - b_i}{b_{i+1} - b_i}}
|
| 3426 |
-
\
|
| 3427 |
-
\mbox{ for } b_i \le x < b_{i+1}
|
| 3428 |
-
\; \mbox{.}$$
|
| 3429 |
|
| 3430 |
The n + 1 distribution parameters bᵢ, also known as this distribution’s
|
| 3431 |
*interval boundaries* , shall satisfy the relation bᵢ < bᵢ₊₁ for
|
| 3432 |
i = 0, …, n - 1. Unless specified otherwise, the remaining n + 1
|
| 3433 |
-
distribution parameters are calculated as
|
| 3434 |
-
|
| 3435 |
-
|
| 3436 |
-
|
| 3437 |
-
|
| 3438 |
-
0 < S = \frac{1}{2}
|
| 3439 |
-
\cdot \sum_{k=0}^{n-1} (w_k + w_{k+1}) \cdot (b_{k+1} - b_k)
|
| 3440 |
-
\; \mbox{.}$$
|
| 3441 |
|
| 3442 |
``` cpp
|
| 3443 |
template<class RealType = double>
|
| 3444 |
class piecewise_linear_distribution {
|
| 3445 |
public:
|
|
@@ -3486,58 +3789,55 @@ n = 1, ρ₀ = ρ₁ = 1, b₀ = 0, and b₁ = 1.
|
|
| 3486 |
template<class InputIteratorB, class InputIteratorW>
|
| 3487 |
piecewise_linear_distribution(InputIteratorB firstB, InputIteratorB lastB,
|
| 3488 |
InputIteratorW firstW);
|
| 3489 |
```
|
| 3490 |
|
| 3491 |
-
*
|
| 3492 |
-
|
| 3493 |
-
|
| 3494 |
-
`
|
| 3495 |
-
|
| 3496 |
-
|
| 3497 |
-
|
| 3498 |
-
|
| 3499 |
-
|
| 3500 |
-
n+1, and any wₖ for k ≥ n+1 shall be ignored by the distribution.
|
| 3501 |
|
| 3502 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3503 |
parameters as specified above.
|
| 3504 |
|
| 3505 |
``` cpp
|
| 3506 |
template<class UnaryOperation>
|
| 3507 |
piecewise_linear_distribution(initializer_list<RealType> bl, UnaryOperation fw);
|
| 3508 |
```
|
| 3509 |
|
| 3510 |
-
*
|
| 3511 |
-
|
| 3512 |
-
`double`. Moreover, `double` shall be convertible to the type of
|
| 3513 |
-
`UnaryOperation`’s sole parameter.
|
| 3514 |
|
| 3515 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3516 |
parameters taken or calculated from the following values: If
|
| 3517 |
`bl.size()` < 2, let n = 1, ρ₀ = ρ₁ = 1, b₀ = 0, and b₁ = 1. Otherwise,
|
| 3518 |
let [`bl.begin(),` `bl.end()`) form a sequence b₀, …, bₙ, and let
|
| 3519 |
wₖ = `fw`(bₖ) for k = 0, …, n.
|
| 3520 |
|
| 3521 |
-
*Complexity:* The number of invocations of `fw`
|
| 3522 |
|
| 3523 |
``` cpp
|
| 3524 |
template<class UnaryOperation>
|
| 3525 |
piecewise_linear_distribution(size_t nw, RealType xmin, RealType xmax, UnaryOperation fw);
|
| 3526 |
```
|
| 3527 |
|
| 3528 |
-
*
|
| 3529 |
-
|
| 3530 |
-
|
| 3531 |
-
|
| 3532 |
-
|
| 3533 |
|
| 3534 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3535 |
parameters taken or calculated from the following values: Let
|
| 3536 |
bₖ = `xmin` + k ⋅ δ for k = 0, …, n, and wₖ = `fw`(bₖ) for k = 0, …, n.
|
| 3537 |
|
| 3538 |
-
*Complexity:* The number of invocations of `fw`
|
| 3539 |
|
| 3540 |
``` cpp
|
| 3541 |
vector<result_type> intervals() const;
|
| 3542 |
```
|
| 3543 |
|
|
@@ -3553,12 +3853,12 @@ vector<result_type> densities() const;
|
|
| 3553 |
whose `operator[]` member returns ρₖ when invoked with argument k for
|
| 3554 |
k = 0, …, n.
|
| 3555 |
|
| 3556 |
### Low-quality random number generation <a id="c.math.rand">[[c.math.rand]]</a>
|
| 3557 |
|
| 3558 |
-
[*Note 1*: The header `<cstdlib>`
|
| 3559 |
-
|
| 3560 |
|
| 3561 |
``` cpp
|
| 3562 |
int rand();
|
| 3563 |
void srand(unsigned int seed);
|
| 3564 |
```
|
|
@@ -3566,19 +3866,19 @@ void srand(unsigned int seed);
|
|
| 3566 |
*Effects:* The `rand` and `srand` functions have the semantics specified
|
| 3567 |
in the C standard library.
|
| 3568 |
|
| 3569 |
*Remarks:* The implementation may specify that particular library
|
| 3570 |
functions may call `rand`. It is *implementation-defined* whether the
|
| 3571 |
-
`rand` function may introduce data races
|
| 3572 |
|
| 3573 |
[*Note 1*: The other random number generation facilities in this
|
| 3574 |
-
|
| 3575 |
-
|
| 3576 |
-
|
| 3577 |
-
|
| 3578 |
|
| 3579 |
-
ISO C 7.22.2
|
| 3580 |
|
| 3581 |
## Numeric arrays <a id="numarray">[[numarray]]</a>
|
| 3582 |
|
| 3583 |
### Header `<valarray>` synopsis <a id="valarray.syn">[[valarray.syn]]</a>
|
| 3584 |
|
|
@@ -3595,101 +3895,133 @@ namespace std {
|
|
| 3595 |
template<class T> class indirect_array; // an indirected array
|
| 3596 |
|
| 3597 |
template<class T> void swap(valarray<T>&, valarray<T>&) noexcept;
|
| 3598 |
|
| 3599 |
template<class T> valarray<T> operator* (const valarray<T>&, const valarray<T>&);
|
| 3600 |
-
template<class T> valarray<T> operator* (const valarray<T>&,
|
| 3601 |
-
|
|
|
|
|
|
|
| 3602 |
|
| 3603 |
template<class T> valarray<T> operator/ (const valarray<T>&, const valarray<T>&);
|
| 3604 |
-
template<class T> valarray<T> operator/ (const valarray<T>&,
|
| 3605 |
-
|
|
|
|
|
|
|
| 3606 |
|
| 3607 |
template<class T> valarray<T> operator% (const valarray<T>&, const valarray<T>&);
|
| 3608 |
-
template<class T> valarray<T> operator% (const valarray<T>&,
|
| 3609 |
-
|
|
|
|
|
|
|
| 3610 |
|
| 3611 |
template<class T> valarray<T> operator+ (const valarray<T>&, const valarray<T>&);
|
| 3612 |
-
template<class T> valarray<T> operator+ (const valarray<T>&,
|
| 3613 |
-
|
|
|
|
|
|
|
| 3614 |
|
| 3615 |
template<class T> valarray<T> operator- (const valarray<T>&, const valarray<T>&);
|
| 3616 |
-
template<class T> valarray<T> operator- (const valarray<T>&,
|
| 3617 |
-
|
|
|
|
|
|
|
| 3618 |
|
| 3619 |
template<class T> valarray<T> operator^ (const valarray<T>&, const valarray<T>&);
|
| 3620 |
-
template<class T> valarray<T> operator^ (const valarray<T>&,
|
| 3621 |
-
|
|
|
|
|
|
|
| 3622 |
|
| 3623 |
template<class T> valarray<T> operator& (const valarray<T>&, const valarray<T>&);
|
| 3624 |
-
template<class T> valarray<T> operator& (const valarray<T>&,
|
| 3625 |
-
|
|
|
|
|
|
|
| 3626 |
|
| 3627 |
template<class T> valarray<T> operator| (const valarray<T>&, const valarray<T>&);
|
| 3628 |
-
template<class T> valarray<T> operator| (const valarray<T>&,
|
| 3629 |
-
|
|
|
|
|
|
|
| 3630 |
|
| 3631 |
template<class T> valarray<T> operator<<(const valarray<T>&, const valarray<T>&);
|
| 3632 |
-
template<class T> valarray<T> operator<<(const valarray<T>&,
|
| 3633 |
-
|
|
|
|
|
|
|
| 3634 |
|
| 3635 |
template<class T> valarray<T> operator>>(const valarray<T>&, const valarray<T>&);
|
| 3636 |
-
template<class T> valarray<T> operator>>(const valarray<T>&,
|
| 3637 |
-
|
|
|
|
|
|
|
| 3638 |
|
| 3639 |
template<class T> valarray<bool> operator&&(const valarray<T>&, const valarray<T>&);
|
| 3640 |
-
template<class T> valarray<bool> operator&&(const valarray<T>&,
|
| 3641 |
-
|
|
|
|
|
|
|
| 3642 |
|
| 3643 |
template<class T> valarray<bool> operator||(const valarray<T>&, const valarray<T>&);
|
| 3644 |
-
template<class T> valarray<bool> operator||(const valarray<T>&,
|
| 3645 |
-
|
|
|
|
|
|
|
| 3646 |
|
| 3647 |
-
template<class T>
|
| 3648 |
-
|
| 3649 |
-
|
| 3650 |
-
template<class T> valarray<bool> operator==(const
|
| 3651 |
-
|
| 3652 |
-
|
| 3653 |
-
template<class T> valarray<bool> operator!=(const valarray<T>&,
|
| 3654 |
-
|
|
|
|
|
|
|
| 3655 |
|
| 3656 |
-
template<class T>
|
| 3657 |
-
|
| 3658 |
-
|
| 3659 |
-
template<class T> valarray<bool> operator< (const
|
| 3660 |
-
|
| 3661 |
-
|
| 3662 |
-
template<class T> valarray<bool> operator> (const valarray<T>&,
|
| 3663 |
-
|
| 3664 |
-
template<class T>
|
| 3665 |
-
|
| 3666 |
-
template<class T> valarray<bool> operator<=(const valarray<T>&, const T&);
|
| 3667 |
-
template<class T> valarray<bool> operator<=(const
|
| 3668 |
-
|
| 3669 |
-
|
| 3670 |
-
|
| 3671 |
-
template<class T> valarray<bool> operator>=(const T&, const valarray<T>&);
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3672 |
|
| 3673 |
template<class T> valarray<T> abs (const valarray<T>&);
|
| 3674 |
template<class T> valarray<T> acos (const valarray<T>&);
|
| 3675 |
template<class T> valarray<T> asin (const valarray<T>&);
|
| 3676 |
template<class T> valarray<T> atan (const valarray<T>&);
|
| 3677 |
|
| 3678 |
template<class T> valarray<T> atan2(const valarray<T>&, const valarray<T>&);
|
| 3679 |
-
template<class T> valarray<T> atan2(const valarray<T>&,
|
| 3680 |
-
|
|
|
|
|
|
|
| 3681 |
|
| 3682 |
template<class T> valarray<T> cos (const valarray<T>&);
|
| 3683 |
template<class T> valarray<T> cosh (const valarray<T>&);
|
| 3684 |
template<class T> valarray<T> exp (const valarray<T>&);
|
| 3685 |
template<class T> valarray<T> log (const valarray<T>&);
|
| 3686 |
template<class T> valarray<T> log10(const valarray<T>&);
|
| 3687 |
|
| 3688 |
template<class T> valarray<T> pow(const valarray<T>&, const valarray<T>&);
|
| 3689 |
-
template<class T> valarray<T> pow(const valarray<T>&, const T&);
|
| 3690 |
-
template<class T> valarray<T> pow(const T&, const valarray<T>&);
|
| 3691 |
|
| 3692 |
template<class T> valarray<T> sin (const valarray<T>&);
|
| 3693 |
template<class T> valarray<T> sinh (const valarray<T>&);
|
| 3694 |
template<class T> valarray<T> sqrt (const valarray<T>&);
|
| 3695 |
template<class T> valarray<T> tan (const valarray<T>&);
|
|
@@ -3718,28 +4050,28 @@ nested argument type.[^7]
|
|
| 3718 |
|
| 3719 |
Implementations introducing such replacement types shall provide
|
| 3720 |
additional functions and operators as follows:
|
| 3721 |
|
| 3722 |
- for every function taking a `const valarray<T>&` other than `begin`
|
| 3723 |
-
and `end`
|
| 3724 |
replacement types shall be added;
|
| 3725 |
- for every function taking two `const valarray<T>&` arguments,
|
| 3726 |
identical functions taking every combination of `const valarray<T>&`
|
| 3727 |
and replacement types shall be added.
|
| 3728 |
|
| 3729 |
In particular, an implementation shall allow a `valarray<T>` to be
|
| 3730 |
constructed from such replacement types and shall allow assignments and
|
| 3731 |
compound assignments of such types to `valarray<T>`, `slice_array<T>`,
|
| 3732 |
`gslice_array<T>`, `mask_array<T>` and `indirect_array<T>` objects.
|
| 3733 |
|
| 3734 |
-
These library functions are permitted to throw a `bad_alloc`
|
| 3735 |
-
[[bad.alloc]]
|
| 3736 |
to carry out the operation. Note that the exception is not mandated.
|
| 3737 |
|
| 3738 |
### Class template `valarray` <a id="template.valarray">[[template.valarray]]</a>
|
| 3739 |
|
| 3740 |
-
####
|
| 3741 |
|
| 3742 |
``` cpp
|
| 3743 |
namespace std {
|
| 3744 |
template<class T> class valarray {
|
| 3745 |
public:
|
|
@@ -3839,14 +4171,11 @@ object of type `valarray<T>` is referred to as an “array” throughout the
|
|
| 3839 |
remainder of [[numarray]]. The illusion of higher dimensionality may be
|
| 3840 |
produced by the familiar idiom of computed indices, together with the
|
| 3841 |
powerful subsetting capabilities provided by the generalized subscript
|
| 3842 |
operators.[^8]
|
| 3843 |
|
| 3844 |
-
|
| 3845 |
-
in `<valarray>` as `inline`.
|
| 3846 |
-
|
| 3847 |
-
#### `valarray` constructors <a id="valarray.cons">[[valarray.cons]]</a>
|
| 3848 |
|
| 3849 |
``` cpp
|
| 3850 |
valarray();
|
| 3851 |
```
|
| 3852 |
|
|
@@ -3855,11 +4184,11 @@ valarray();
|
|
| 3855 |
``` cpp
|
| 3856 |
explicit valarray(size_t n);
|
| 3857 |
```
|
| 3858 |
|
| 3859 |
*Effects:* Constructs a `valarray` that has length `n`. Each element of
|
| 3860 |
-
the array is value-initialized
|
| 3861 |
|
| 3862 |
``` cpp
|
| 3863 |
valarray(const T& v, size_t n);
|
| 3864 |
```
|
| 3865 |
|
|
@@ -3868,12 +4197,11 @@ the array is initialized with `v`.
|
|
| 3868 |
|
| 3869 |
``` cpp
|
| 3870 |
valarray(const T* p, size_t n);
|
| 3871 |
```
|
| 3872 |
|
| 3873 |
-
*
|
| 3874 |
-
elements.
|
| 3875 |
|
| 3876 |
*Effects:* Constructs a `valarray` that has length `n`. The values of
|
| 3877 |
the elements of the array are initialized with the first `n` values
|
| 3878 |
pointed to by the first argument.[^10]
|
| 3879 |
|
|
@@ -3916,11 +4244,11 @@ templates to a `valarray`.
|
|
| 3916 |
```
|
| 3917 |
|
| 3918 |
*Effects:* The destructor is applied to every element of `*this`; an
|
| 3919 |
implementation may return all allocated memory.
|
| 3920 |
|
| 3921 |
-
####
|
| 3922 |
|
| 3923 |
``` cpp
|
| 3924 |
valarray& operator=(const valarray& v);
|
| 3925 |
```
|
| 3926 |
|
|
@@ -3928,11 +4256,11 @@ valarray& operator=(const valarray& v);
|
|
| 3928 |
the corresponding element of `v`. If the length of `v` is not equal to
|
| 3929 |
the length of `*this`, resizes `*this` to make the two arrays the same
|
| 3930 |
length, as if by calling `resize(v.size())`, before performing the
|
| 3931 |
assignment.
|
| 3932 |
|
| 3933 |
-
*
|
| 3934 |
|
| 3935 |
*Returns:* `*this`.
|
| 3936 |
|
| 3937 |
``` cpp
|
| 3938 |
valarray& operator=(valarray&& v) noexcept;
|
|
@@ -3964,63 +4292,64 @@ valarray& operator=(const slice_array<T>&);
|
|
| 3964 |
valarray& operator=(const gslice_array<T>&);
|
| 3965 |
valarray& operator=(const mask_array<T>&);
|
| 3966 |
valarray& operator=(const indirect_array<T>&);
|
| 3967 |
```
|
| 3968 |
|
| 3969 |
-
*
|
| 3970 |
-
`size()`. The value of an element in the left-hand side of a
|
| 3971 |
-
assignment operator does not depend on the value of another
|
| 3972 |
-
that left-hand side.
|
| 3973 |
|
| 3974 |
These operators allow the results of a generalized subscripting
|
| 3975 |
operation to be assigned directly to a `valarray`.
|
| 3976 |
|
| 3977 |
-
####
|
| 3978 |
|
| 3979 |
``` cpp
|
| 3980 |
const T& operator[](size_t n) const;
|
| 3981 |
T& operator[](size_t n);
|
| 3982 |
```
|
| 3983 |
|
| 3984 |
-
*
|
| 3985 |
|
| 3986 |
*Returns:* A reference to the corresponding element of the array.
|
| 3987 |
|
| 3988 |
[*Note 1*: The expression `(a[i] = q, a[i]) == q` evaluates to `true`
|
| 3989 |
for any non-constant `valarray<T> a`, any `T q`, and for any `size_t i`
|
| 3990 |
such that the value of `i` is less than the length of
|
| 3991 |
`a`. — *end note*]
|
| 3992 |
|
| 3993 |
-
*Remarks:* The expression `
|
| 3994 |
-
all `size_t i` and `size_t j` such that
|
|
|
|
| 3995 |
|
| 3996 |
-
The expression `
|
| 3997 |
-
`a` and `b` and for any `size_t i` and `size_t j`
|
| 3998 |
-
`i < a.size()` and `j < b.size()`.
|
| 3999 |
|
| 4000 |
[*Note 2*: This property indicates an absence of aliasing and may be
|
| 4001 |
used to advantage by optimizing compilers. Compilers may take advantage
|
| 4002 |
of inlining, constant propagation, loop fusion, tracking of pointers
|
| 4003 |
obtained from `operator new`, and other techniques to generate efficient
|
| 4004 |
`valarray`s. — *end note*]
|
| 4005 |
|
| 4006 |
The reference returned by the subscript operator for an array shall be
|
| 4007 |
-
valid until the member function
|
| 4008 |
-
|
| 4009 |
-
|
| 4010 |
|
| 4011 |
-
####
|
| 4012 |
|
| 4013 |
The member `operator[]` is overloaded to provide several ways to select
|
| 4014 |
sequences of elements from among those controlled by `*this`. Each of
|
| 4015 |
these operations returns a subset of the array. The const-qualified
|
| 4016 |
versions return this subset as a new `valarray` object. The non-const
|
| 4017 |
versions return a class template object which has reference semantics to
|
| 4018 |
the original array, working in conjunction with various overloads of
|
| 4019 |
`operator=` and other assigning operators to allow selective replacement
|
| 4020 |
(slicing) of the controlled sequence. In each case the selected
|
| 4021 |
-
element(s)
|
| 4022 |
|
| 4023 |
``` cpp
|
| 4024 |
valarray operator[](slice slicearr) const;
|
| 4025 |
```
|
| 4026 |
|
|
@@ -4167,30 +4496,29 @@ v0[valarray<size_t>(vi, 5)] = v1;
|
|
| 4167 |
// v0 == valarray<char>("abCDeBgAEjklmnop", 16)
|
| 4168 |
```
|
| 4169 |
|
| 4170 |
— *end example*]
|
| 4171 |
|
| 4172 |
-
####
|
| 4173 |
|
| 4174 |
``` cpp
|
| 4175 |
valarray operator+() const;
|
| 4176 |
valarray operator-() const;
|
| 4177 |
valarray operator~() const;
|
| 4178 |
valarray<bool> operator!() const;
|
| 4179 |
```
|
| 4180 |
|
| 4181 |
-
*
|
| 4182 |
-
`T`
|
| 4183 |
-
|
| 4184 |
-
`operator!`)
|
| 4185 |
-
`T` (`bool` for `operator!`).
|
| 4186 |
|
| 4187 |
*Returns:* A `valarray` whose length is `size()`. Each element of the
|
| 4188 |
returned array is initialized with the result of applying the indicated
|
| 4189 |
operator to the corresponding element of the array.
|
| 4190 |
|
| 4191 |
-
####
|
| 4192 |
|
| 4193 |
``` cpp
|
| 4194 |
valarray& operator*= (const valarray& v);
|
| 4195 |
valarray& operator/= (const valarray& v);
|
| 4196 |
valarray& operator%= (const valarray& v);
|
|
@@ -4201,15 +4529,18 @@ valarray& operator&= (const valarray& v);
|
|
| 4201 |
valarray& operator|= (const valarray& v);
|
| 4202 |
valarray& operator<<=(const valarray& v);
|
| 4203 |
valarray& operator>>=(const valarray& v);
|
| 4204 |
```
|
| 4205 |
|
| 4206 |
-
*
|
| 4207 |
-
|
| 4208 |
-
|
| 4209 |
-
|
| 4210 |
-
|
|
|
|
|
|
|
|
|
|
| 4211 |
|
| 4212 |
*Effects:* Each of these operators performs the indicated operation on
|
| 4213 |
each of the elements of `*this` and the corresponding element of `v`.
|
| 4214 |
|
| 4215 |
*Returns:* `*this`.
|
|
@@ -4228,24 +4559,23 @@ valarray& operator&= (const T& v);
|
|
| 4228 |
valarray& operator|= (const T& v);
|
| 4229 |
valarray& operator<<=(const T& v);
|
| 4230 |
valarray& operator>>=(const T& v);
|
| 4231 |
```
|
| 4232 |
|
| 4233 |
-
*
|
| 4234 |
-
`T`
|
| 4235 |
-
`T`.
|
| 4236 |
|
| 4237 |
*Effects:* Each of these operators applies the indicated operation to
|
| 4238 |
each element of `*this` and `v`.
|
| 4239 |
|
| 4240 |
*Returns:* `*this`
|
| 4241 |
|
| 4242 |
*Remarks:* The appearance of an array on the left-hand side of a
|
| 4243 |
compound assignment does not invalidate references or pointers to the
|
| 4244 |
elements of the array.
|
| 4245 |
|
| 4246 |
-
####
|
| 4247 |
|
| 4248 |
``` cpp
|
| 4249 |
void swap(valarray& v) noexcept;
|
| 4250 |
```
|
| 4251 |
|
|
@@ -4264,33 +4594,34 @@ size_t size() const;
|
|
| 4264 |
|
| 4265 |
``` cpp
|
| 4266 |
T sum() const;
|
| 4267 |
```
|
| 4268 |
|
| 4269 |
-
*
|
| 4270 |
-
|
|
|
|
| 4271 |
|
| 4272 |
*Returns:* The sum of all the elements of the array. If the array has
|
| 4273 |
length 1, returns the value of element 0. Otherwise, the returned value
|
| 4274 |
is calculated by applying `operator+=` to a copy of an element of the
|
| 4275 |
array and all other elements of the array in an unspecified order.
|
| 4276 |
|
| 4277 |
``` cpp
|
| 4278 |
T min() const;
|
| 4279 |
```
|
| 4280 |
|
| 4281 |
-
*
|
| 4282 |
|
| 4283 |
*Returns:* The minimum value contained in `*this`. For an array of
|
| 4284 |
length 1, the value of element 0 is returned. For all other array
|
| 4285 |
lengths, the determination is made using `operator<`.
|
| 4286 |
|
| 4287 |
``` cpp
|
| 4288 |
T max() const;
|
| 4289 |
```
|
| 4290 |
|
| 4291 |
-
*
|
| 4292 |
|
| 4293 |
*Returns:* The maximum value contained in `*this`. For an array of
|
| 4294 |
length 1, the value of element 0 is returned. For all other array
|
| 4295 |
lengths, the determination is made using `operator<`.
|
| 4296 |
|
|
@@ -4305,13 +4636,13 @@ is `(*this)[`*`I`*` + n]` if *`I`*` + n` is non-negative and less than
|
|
| 4305 |
[*Note 1*: If element zero is taken as the leftmost element, a positive
|
| 4306 |
value of `n` shifts the elements left `n` places, with zero
|
| 4307 |
fill. — *end note*]
|
| 4308 |
|
| 4309 |
[*Example 1*: If the argument has the value -2, the first two elements
|
| 4310 |
-
of the result will be value-initialized
|
| 4311 |
-
|
| 4312 |
-
|
| 4313 |
|
| 4314 |
``` cpp
|
| 4315 |
valarray cshift(int n) const;
|
| 4316 |
```
|
| 4317 |
|
|
@@ -4337,183 +4668,197 @@ void resize(size_t sz, T c = T());
|
|
| 4337 |
assigns to each element the value of the second argument. Resizing
|
| 4338 |
invalidates all pointers and references to elements in the array.
|
| 4339 |
|
| 4340 |
### `valarray` non-member operations <a id="valarray.nonmembers">[[valarray.nonmembers]]</a>
|
| 4341 |
|
| 4342 |
-
####
|
| 4343 |
|
| 4344 |
``` cpp
|
| 4345 |
-
template<class T> valarray<T> operator*
|
| 4346 |
-
|
| 4347 |
-
template<class T> valarray<T> operator
|
| 4348 |
-
|
| 4349 |
-
template<class T> valarray<T> operator
|
| 4350 |
-
|
| 4351 |
-
template<class T> valarray<T> operator
|
| 4352 |
-
|
| 4353 |
-
template<class T> valarray<T> operator
|
| 4354 |
-
|
| 4355 |
-
template<class T> valarray<T> operator^
|
| 4356 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4357 |
-
template<class T> valarray<T> operator&
|
| 4358 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4359 |
-
template<class T> valarray<T> operator|
|
| 4360 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4361 |
-
template<class T> valarray<T> operator<<
|
| 4362 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4363 |
-
template<class T> valarray<T> operator>>
|
| 4364 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4365 |
```
|
| 4366 |
|
| 4367 |
-
*
|
| 4368 |
-
`T`
|
| 4369 |
-
|
| 4370 |
-
|
| 4371 |
-
the same length.
|
| 4372 |
|
| 4373 |
*Returns:* A `valarray` whose length is equal to the lengths of the
|
| 4374 |
argument arrays. Each element of the returned array is initialized with
|
| 4375 |
the result of applying the indicated operator to the corresponding
|
| 4376 |
elements of the argument arrays.
|
| 4377 |
|
| 4378 |
``` cpp
|
| 4379 |
-
template<class T> valarray<T> operator* (const valarray<T>&,
|
| 4380 |
-
|
| 4381 |
-
template<class T> valarray<T> operator
|
| 4382 |
-
|
| 4383 |
-
template<class T> valarray<T> operator
|
| 4384 |
-
|
| 4385 |
-
template<class T> valarray<T> operator
|
| 4386 |
-
|
| 4387 |
-
template<class T> valarray<T> operator
|
| 4388 |
-
|
| 4389 |
-
template<class T> valarray<T> operator
|
| 4390 |
-
|
| 4391 |
-
template<class T> valarray<T> operator
|
| 4392 |
-
|
| 4393 |
-
template<class T> valarray<T> operator
|
| 4394 |
-
|
| 4395 |
-
template<class T> valarray<T> operator
|
| 4396 |
-
|
| 4397 |
-
template<class T> valarray<T> operator
|
| 4398 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 4399 |
```
|
| 4400 |
|
| 4401 |
-
*
|
| 4402 |
-
`T`
|
| 4403 |
-
|
| 4404 |
-
unambiguously implicitly converted to type `T`.
|
| 4405 |
|
| 4406 |
*Returns:* A `valarray` whose length is equal to the length of the array
|
| 4407 |
argument. Each element of the returned array is initialized with the
|
| 4408 |
result of applying the indicated operator to the corresponding element
|
| 4409 |
of the array argument and the non-array argument.
|
| 4410 |
|
| 4411 |
-
####
|
| 4412 |
|
| 4413 |
``` cpp
|
| 4414 |
-
template<class T> valarray<bool> operator==
|
| 4415 |
-
|
| 4416 |
-
template<class T> valarray<bool> operator
|
| 4417 |
-
|
| 4418 |
-
template<class T> valarray<bool> operator<
|
| 4419 |
-
|
| 4420 |
-
template<class T> valarray<bool> operator>
|
| 4421 |
-
|
| 4422 |
-
template<class T> valarray<bool> operator<=
|
| 4423 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4424 |
-
template<class T> valarray<bool> operator>=
|
| 4425 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4426 |
-
template<class T> valarray<bool> operator&&
|
| 4427 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4428 |
-
template<class T> valarray<bool> operator||
|
| 4429 |
-
(const valarray<T>&, const valarray<T>&);
|
| 4430 |
```
|
| 4431 |
|
| 4432 |
-
*
|
| 4433 |
-
`T`
|
| 4434 |
-
|
| 4435 |
-
|
| 4436 |
-
arguments have the same length.
|
| 4437 |
|
| 4438 |
*Returns:* A `valarray<bool>` whose length is equal to the length of the
|
| 4439 |
array arguments. Each element of the returned array is initialized with
|
| 4440 |
the result of applying the indicated operator to the corresponding
|
| 4441 |
elements of the argument arrays.
|
| 4442 |
|
| 4443 |
``` cpp
|
| 4444 |
-
template<class T> valarray<bool> operator==(const valarray<T>&,
|
| 4445 |
-
|
| 4446 |
-
template<class T> valarray<bool> operator
|
| 4447 |
-
|
| 4448 |
-
template<class T> valarray<bool> operator
|
| 4449 |
-
|
| 4450 |
-
template<class T> valarray<bool> operator
|
| 4451 |
-
|
| 4452 |
-
template<class T> valarray<bool> operator<
|
| 4453 |
-
|
| 4454 |
-
template<class T> valarray<bool> operator
|
| 4455 |
-
|
| 4456 |
-
template<class T> valarray<bool> operator
|
| 4457 |
-
|
| 4458 |
-
template<class T> valarray<bool> operator
|
| 4459 |
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 4460 |
```
|
| 4461 |
|
| 4462 |
-
*
|
| 4463 |
-
`T`
|
| 4464 |
-
|
| 4465 |
-
be unambiguously implicitly converted to type `bool`.
|
| 4466 |
|
| 4467 |
*Returns:* A `valarray<bool>` whose length is equal to the length of the
|
| 4468 |
array argument. Each element of the returned array is initialized with
|
| 4469 |
the result of applying the indicated operator to the corresponding
|
| 4470 |
element of the array and the non-array argument.
|
| 4471 |
|
| 4472 |
-
####
|
| 4473 |
|
| 4474 |
``` cpp
|
| 4475 |
template<class T> valarray<T> abs (const valarray<T>&);
|
| 4476 |
template<class T> valarray<T> acos (const valarray<T>&);
|
| 4477 |
template<class T> valarray<T> asin (const valarray<T>&);
|
| 4478 |
template<class T> valarray<T> atan (const valarray<T>&);
|
| 4479 |
-
template<class T> valarray<T> atan2
|
| 4480 |
-
|
| 4481 |
-
template<class T> valarray<T> atan2(const valarray<T>&, const T&);
|
| 4482 |
-
template<class T> valarray<T> atan2(const T&, const valarray<T>&);
|
| 4483 |
template<class T> valarray<T> cos (const valarray<T>&);
|
| 4484 |
template<class T> valarray<T> cosh (const valarray<T>&);
|
| 4485 |
template<class T> valarray<T> exp (const valarray<T>&);
|
| 4486 |
template<class T> valarray<T> log (const valarray<T>&);
|
| 4487 |
template<class T> valarray<T> log10(const valarray<T>&);
|
| 4488 |
-
template<class T> valarray<T> pow
|
| 4489 |
-
|
| 4490 |
-
template<class T> valarray<T> pow (const valarray<T>&, const T&);
|
| 4491 |
-
template<class T> valarray<T> pow (const T&, const valarray<T>&);
|
| 4492 |
template<class T> valarray<T> sin (const valarray<T>&);
|
| 4493 |
template<class T> valarray<T> sinh (const valarray<T>&);
|
| 4494 |
template<class T> valarray<T> sqrt (const valarray<T>&);
|
| 4495 |
template<class T> valarray<T> tan (const valarray<T>&);
|
| 4496 |
template<class T> valarray<T> tanh (const valarray<T>&);
|
| 4497 |
```
|
| 4498 |
|
| 4499 |
-
*
|
| 4500 |
-
|
| 4501 |
-
|
| 4502 |
-
|
| 4503 |
|
| 4504 |
-
####
|
| 4505 |
|
| 4506 |
``` cpp
|
| 4507 |
template<class T> void swap(valarray<T>& x, valarray<T>& y) noexcept;
|
| 4508 |
```
|
| 4509 |
|
| 4510 |
*Effects:* Equivalent to `x.swap(y)`.
|
| 4511 |
|
| 4512 |
### Class `slice` <a id="class.slice">[[class.slice]]</a>
|
| 4513 |
|
| 4514 |
-
####
|
| 4515 |
|
| 4516 |
``` cpp
|
| 4517 |
namespace std {
|
| 4518 |
class slice {
|
| 4519 |
public:
|
|
@@ -4521,18 +4866,20 @@ namespace std {
|
|
| 4521 |
slice(size_t, size_t, size_t);
|
| 4522 |
|
| 4523 |
size_t start() const;
|
| 4524 |
size_t size() const;
|
| 4525 |
size_t stride() const;
|
|
|
|
|
|
|
| 4526 |
};
|
| 4527 |
}
|
| 4528 |
```
|
| 4529 |
|
| 4530 |
The `slice` class represents a BLAS-like slice from an array. Such a
|
| 4531 |
slice is specified by a starting index, a length, and a stride.[^12]
|
| 4532 |
|
| 4533 |
-
####
|
| 4534 |
|
| 4535 |
``` cpp
|
| 4536 |
slice();
|
| 4537 |
slice(size_t start, size_t length, size_t stride);
|
| 4538 |
slice(const slice&);
|
|
@@ -4542,13 +4889,13 @@ The default constructor is equivalent to `slice(0, 0, 0)`. A default
|
|
| 4542 |
constructor is provided only to permit the declaration of arrays of
|
| 4543 |
slices. The constructor with arguments for a slice takes a start,
|
| 4544 |
length, and stride parameter.
|
| 4545 |
|
| 4546 |
[*Example 1*: `slice(3, 8, 2)` constructs a slice which selects
|
| 4547 |
-
elements 3, 5, 7,
|
| 4548 |
|
| 4549 |
-
####
|
| 4550 |
|
| 4551 |
``` cpp
|
| 4552 |
size_t start() const;
|
| 4553 |
size_t size() const;
|
| 4554 |
size_t stride() const;
|
|
@@ -4556,13 +4903,25 @@ size_t stride() const;
|
|
| 4556 |
|
| 4557 |
*Returns:* The start, length, or stride specified by a `slice` object.
|
| 4558 |
|
| 4559 |
*Complexity:* Constant time.
|
| 4560 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 4561 |
### Class template `slice_array` <a id="template.slice.array">[[template.slice.array]]</a>
|
| 4562 |
|
| 4563 |
-
####
|
| 4564 |
|
| 4565 |
``` cpp
|
| 4566 |
namespace std {
|
| 4567 |
template<class T> class slice_array {
|
| 4568 |
public:
|
|
@@ -4588,37 +4947,37 @@ namespace std {
|
|
| 4588 |
slice_array() = delete; // as implied by declaring copy constructor above
|
| 4589 |
};
|
| 4590 |
}
|
| 4591 |
```
|
| 4592 |
|
| 4593 |
-
|
| 4594 |
-
|
| 4595 |
|
| 4596 |
``` cpp
|
| 4597 |
slice_array<T> valarray<T>::operator[](slice);
|
| 4598 |
```
|
| 4599 |
|
| 4600 |
It has reference semantics to a subset of an array specified by a
|
| 4601 |
`slice` object.
|
| 4602 |
|
| 4603 |
[*Example 1*: The expression `a[slice(1, 5, 3)] = b;` has the effect of
|
| 4604 |
assigning the elements of `b` to a slice of the elements in `a`. For the
|
| 4605 |
-
slice shown, the elements selected from `a` are
|
| 4606 |
-
13. — *end example*]
|
| 4607 |
|
| 4608 |
-
####
|
| 4609 |
|
| 4610 |
``` cpp
|
| 4611 |
void operator=(const valarray<T>&) const;
|
| 4612 |
const slice_array& operator=(const slice_array&) const;
|
| 4613 |
```
|
| 4614 |
|
| 4615 |
These assignment operators have reference semantics, assigning the
|
| 4616 |
values of the argument array elements to selected elements of the
|
| 4617 |
`valarray<T>` object to which the `slice_array` object refers.
|
| 4618 |
|
| 4619 |
-
####
|
| 4620 |
|
| 4621 |
``` cpp
|
| 4622 |
void operator*= (const valarray<T>&) const;
|
| 4623 |
void operator/= (const valarray<T>&) const;
|
| 4624 |
void operator%= (const valarray<T>&) const;
|
|
@@ -4634,11 +4993,11 @@ void operator>>=(const valarray<T>&) const;
|
|
| 4634 |
These compound assignments have reference semantics, applying the
|
| 4635 |
indicated operation to the elements of the argument array and selected
|
| 4636 |
elements of the `valarray<T>` object to which the `slice_array` object
|
| 4637 |
refers.
|
| 4638 |
|
| 4639 |
-
####
|
| 4640 |
|
| 4641 |
``` cpp
|
| 4642 |
void operator=(const T&) const;
|
| 4643 |
```
|
| 4644 |
|
|
@@ -4646,11 +5005,11 @@ This function has reference semantics, assigning the value of its
|
|
| 4646 |
argument to the elements of the `valarray<T>` object to which the
|
| 4647 |
`slice_array` object refers.
|
| 4648 |
|
| 4649 |
### The `gslice` class <a id="class.gslice">[[class.gslice]]</a>
|
| 4650 |
|
| 4651 |
-
####
|
| 4652 |
|
| 4653 |
``` cpp
|
| 4654 |
namespace std {
|
| 4655 |
class gslice {
|
| 4656 |
public:
|
|
@@ -4704,11 +5063,11 @@ If the stride parameters in the previous example are changed to {1, 1,
|
|
| 4704 |
— *end example*]
|
| 4705 |
|
| 4706 |
If a degenerate slice is used as the argument to the non-`const` version
|
| 4707 |
of `operator[](const gslice&)`, the behavior is undefined.
|
| 4708 |
|
| 4709 |
-
####
|
| 4710 |
|
| 4711 |
``` cpp
|
| 4712 |
gslice();
|
| 4713 |
gslice(size_t start, const valarray<size_t>& lengths,
|
| 4714 |
const valarray<size_t>& strides);
|
|
@@ -4716,13 +5075,13 @@ gslice(const gslice&);
|
|
| 4716 |
```
|
| 4717 |
|
| 4718 |
The default constructor is equivalent to
|
| 4719 |
`gslice(0, valarray<size_t>(), valarray<size_t>())`. The constructor
|
| 4720 |
with arguments builds a `gslice` based on a specification of start,
|
| 4721 |
-
lengths, and strides, as explained in the previous
|
| 4722 |
|
| 4723 |
-
####
|
| 4724 |
|
| 4725 |
``` cpp
|
| 4726 |
size_t start() const;
|
| 4727 |
valarray<size_t> size() const;
|
| 4728 |
valarray<size_t> stride() const;
|
|
@@ -4734,11 +5093,11 @@ specified for the `gslice`.
|
|
| 4734 |
*Complexity:* `start()` is constant time. `size()` and `stride()` are
|
| 4735 |
linear in the number of strides.
|
| 4736 |
|
| 4737 |
### Class template `gslice_array` <a id="template.gslice.array">[[template.gslice.array]]</a>
|
| 4738 |
|
| 4739 |
-
####
|
| 4740 |
|
| 4741 |
``` cpp
|
| 4742 |
namespace std {
|
| 4743 |
template<class T> class gslice_array {
|
| 4744 |
public:
|
|
@@ -4764,36 +5123,34 @@ namespace std {
|
|
| 4764 |
gslice_array() = delete; // as implied by declaring copy constructor above
|
| 4765 |
};
|
| 4766 |
}
|
| 4767 |
```
|
| 4768 |
|
| 4769 |
-
This template is a helper template used by the `
|
| 4770 |
operator
|
| 4771 |
|
| 4772 |
``` cpp
|
| 4773 |
gslice_array<T> valarray<T>::operator[](const gslice&);
|
| 4774 |
```
|
| 4775 |
|
| 4776 |
It has reference semantics to a subset of an array specified by a
|
| 4777 |
-
`gslice` object.
|
|
|
|
|
|
|
| 4778 |
|
| 4779 |
-
|
| 4780 |
-
of assigning the elements of `b` to a generalized slice of the elements
|
| 4781 |
-
in `a`.
|
| 4782 |
-
|
| 4783 |
-
#### `gslice_array` assignment <a id="gslice.array.assign">[[gslice.array.assign]]</a>
|
| 4784 |
|
| 4785 |
``` cpp
|
| 4786 |
void operator=(const valarray<T>&) const;
|
| 4787 |
const gslice_array& operator=(const gslice_array&) const;
|
| 4788 |
```
|
| 4789 |
|
| 4790 |
These assignment operators have reference semantics, assigning the
|
| 4791 |
values of the argument array elements to selected elements of the
|
| 4792 |
`valarray<T>` object to which the `gslice_array` refers.
|
| 4793 |
|
| 4794 |
-
####
|
| 4795 |
|
| 4796 |
``` cpp
|
| 4797 |
void operator*= (const valarray<T>&) const;
|
| 4798 |
void operator/= (const valarray<T>&) const;
|
| 4799 |
void operator%= (const valarray<T>&) const;
|
|
@@ -4809,11 +5166,11 @@ void operator>>=(const valarray<T>&) const;
|
|
| 4809 |
These compound assignments have reference semantics, applying the
|
| 4810 |
indicated operation to the elements of the argument array and selected
|
| 4811 |
elements of the `valarray<T>` object to which the `gslice_array` object
|
| 4812 |
refers.
|
| 4813 |
|
| 4814 |
-
####
|
| 4815 |
|
| 4816 |
``` cpp
|
| 4817 |
void operator=(const T&) const;
|
| 4818 |
```
|
| 4819 |
|
|
@@ -4821,11 +5178,11 @@ This function has reference semantics, assigning the value of its
|
|
| 4821 |
argument to the elements of the `valarray<T>` object to which the
|
| 4822 |
`gslice_array` object refers.
|
| 4823 |
|
| 4824 |
### Class template `mask_array` <a id="template.mask.array">[[template.mask.array]]</a>
|
| 4825 |
|
| 4826 |
-
####
|
| 4827 |
|
| 4828 |
``` cpp
|
| 4829 |
namespace std {
|
| 4830 |
template<class T> class mask_array {
|
| 4831 |
public:
|
|
@@ -4860,24 +5217,24 @@ mask_array<T> valarray<T>::operator[](const valarray<bool>&).
|
|
| 4860 |
```
|
| 4861 |
|
| 4862 |
It has reference semantics to a subset of an array specified by a
|
| 4863 |
boolean mask. Thus, the expression `a[mask] = b;` has the effect of
|
| 4864 |
assigning the elements of `b` to the masked elements in `a` (those for
|
| 4865 |
-
which the corresponding element in `mask` is `true`
|
| 4866 |
|
| 4867 |
-
####
|
| 4868 |
|
| 4869 |
``` cpp
|
| 4870 |
void operator=(const valarray<T>&) const;
|
| 4871 |
const mask_array& operator=(const mask_array&) const;
|
| 4872 |
```
|
| 4873 |
|
| 4874 |
These assignment operators have reference semantics, assigning the
|
| 4875 |
values of the argument array elements to selected elements of the
|
| 4876 |
`valarray<T>` object to which it refers.
|
| 4877 |
|
| 4878 |
-
####
|
| 4879 |
|
| 4880 |
``` cpp
|
| 4881 |
void operator*= (const valarray<T>&) const;
|
| 4882 |
void operator/= (const valarray<T>&) const;
|
| 4883 |
void operator%= (const valarray<T>&) const;
|
|
@@ -4892,11 +5249,11 @@ void operator>>=(const valarray<T>&) const;
|
|
| 4892 |
|
| 4893 |
These compound assignments have reference semantics, applying the
|
| 4894 |
indicated operation to the elements of the argument array and selected
|
| 4895 |
elements of the `valarray<T>` object to which the mask object refers.
|
| 4896 |
|
| 4897 |
-
####
|
| 4898 |
|
| 4899 |
``` cpp
|
| 4900 |
void operator=(const T&) const;
|
| 4901 |
```
|
| 4902 |
|
|
@@ -4904,11 +5261,11 @@ This function has reference semantics, assigning the value of its
|
|
| 4904 |
argument to the elements of the `valarray<T>` object to which the
|
| 4905 |
`mask_array` object refers.
|
| 4906 |
|
| 4907 |
### Class template `indirect_array` <a id="template.indirect.array">[[template.indirect.array]]</a>
|
| 4908 |
|
| 4909 |
-
####
|
| 4910 |
|
| 4911 |
``` cpp
|
| 4912 |
namespace std {
|
| 4913 |
template<class T> class indirect_array {
|
| 4914 |
public:
|
|
@@ -4942,15 +5299,15 @@ operator
|
|
| 4942 |
``` cpp
|
| 4943 |
indirect_array<T> valarray<T>::operator[](const valarray<size_t>&).
|
| 4944 |
```
|
| 4945 |
|
| 4946 |
It has reference semantics to a subset of an array specified by an
|
| 4947 |
-
`indirect_array`. Thus the expression `a[indirect] = b;` has the
|
| 4948 |
-
of assigning the elements of `b` to the elements in `a` whose
|
| 4949 |
-
appear in `indirect`.
|
| 4950 |
|
| 4951 |
-
####
|
| 4952 |
|
| 4953 |
``` cpp
|
| 4954 |
void operator=(const valarray<T>&) const;
|
| 4955 |
const indirect_array& operator=(const indirect_array&) const;
|
| 4956 |
```
|
|
@@ -4974,11 +5331,11 @@ a[indirect] = b;
|
|
| 4974 |
results in undefined behavior since element 4 is specified twice in the
|
| 4975 |
indirection.
|
| 4976 |
|
| 4977 |
— *end example*]
|
| 4978 |
|
| 4979 |
-
####
|
| 4980 |
|
| 4981 |
``` cpp
|
| 4982 |
void operator*= (const valarray<T>&) const;
|
| 4983 |
void operator/= (const valarray<T>&) const;
|
| 4984 |
void operator%= (const valarray<T>&) const;
|
|
@@ -4997,11 +5354,11 @@ elements of the `valarray<T>` object to which the `indirect_array`
|
|
| 4997 |
object refers.
|
| 4998 |
|
| 4999 |
If the `indirect_array` specifies an element in the `valarray<T>` object
|
| 5000 |
to which it refers more than once, the behavior is undefined.
|
| 5001 |
|
| 5002 |
-
####
|
| 5003 |
|
| 5004 |
``` cpp
|
| 5005 |
void operator=(const T&) const;
|
| 5006 |
```
|
| 5007 |
|
|
@@ -5010,22 +5367,22 @@ argument to the elements of the `valarray<T>` object to which the
|
|
| 5010 |
`indirect_array` object refers.
|
| 5011 |
|
| 5012 |
### `valarray` range access <a id="valarray.range">[[valarray.range]]</a>
|
| 5013 |
|
| 5014 |
In the `begin` and `end` function templates that follow, *unspecified*1
|
| 5015 |
-
is a type that meets the requirements of a mutable
|
| 5016 |
-
|
| 5017 |
-
[[iterator.
|
| 5018 |
-
parameter `T` and whose `reference` type is
|
| 5019 |
-
type that meets the requirements of a constant
|
| 5020 |
-
|
| 5021 |
-
|
| 5022 |
-
|
| 5023 |
|
| 5024 |
The iterators returned by `begin` and `end` for an array are guaranteed
|
| 5025 |
-
to be valid until the member function `resize(size_t, T)`
|
| 5026 |
-
[[valarray.members]]
|
| 5027 |
that array ends, whichever happens first.
|
| 5028 |
|
| 5029 |
``` cpp
|
| 5030 |
template<class T> unspecified{1} begin(valarray<T>& v);
|
| 5031 |
template<class T> unspecified{2} begin(const valarray<T>& v);
|
|
@@ -5038,950 +5395,10 @@ template <class T> unspecified{1} end(valarray<T>& v);
|
|
| 5038 |
template<class T> unspecified{2} end(const valarray<T>& v);
|
| 5039 |
```
|
| 5040 |
|
| 5041 |
*Returns:* An iterator referencing one past the last value in the array.
|
| 5042 |
|
| 5043 |
-
## Generalized numeric operations <a id="numeric.ops">[[numeric.ops]]</a>
|
| 5044 |
-
|
| 5045 |
-
### Header `<numeric>` synopsis <a id="numeric.ops.overview">[[numeric.ops.overview]]</a>
|
| 5046 |
-
|
| 5047 |
-
``` cpp
|
| 5048 |
-
namespace std {
|
| 5049 |
-
// [accumulate], accumulate
|
| 5050 |
-
template <class InputIterator, class T>
|
| 5051 |
-
T accumulate(InputIterator first, InputIterator last, T init);
|
| 5052 |
-
template <class InputIterator, class T, class BinaryOperation>
|
| 5053 |
-
T accumulate(InputIterator first, InputIterator last, T init,
|
| 5054 |
-
BinaryOperation binary_op);
|
| 5055 |
-
|
| 5056 |
-
// [reduce], reduce
|
| 5057 |
-
template<class InputIterator>
|
| 5058 |
-
typename iterator_traits<InputIterator>::value_type
|
| 5059 |
-
reduce(InputIterator first, InputIterator last);
|
| 5060 |
-
template<class InputIterator, class T>
|
| 5061 |
-
T reduce(InputIterator first, InputIterator last, T init);
|
| 5062 |
-
template<class InputIterator, class T, class BinaryOperation>
|
| 5063 |
-
T reduce(InputIterator first, InputIterator last, T init,
|
| 5064 |
-
BinaryOperation binary_op);
|
| 5065 |
-
template<class ExecutionPolicy, class ForwardIterator>
|
| 5066 |
-
typename iterator_traits<ForwardIterator>::value_type
|
| 5067 |
-
reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5068 |
-
ForwardIterator first, ForwardIterator last);
|
| 5069 |
-
template<class ExecutionPolicy, class ForwardIterator, class T>
|
| 5070 |
-
T reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5071 |
-
ForwardIterator first, ForwardIterator last, T init);
|
| 5072 |
-
template<class ExecutionPolicy, class ForwardIterator, class T, class BinaryOperation>
|
| 5073 |
-
T reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5074 |
-
ForwardIterator first, ForwardIterator last, T init,
|
| 5075 |
-
BinaryOperation binary_op);
|
| 5076 |
-
|
| 5077 |
-
// [inner.product], inner product
|
| 5078 |
-
template <class InputIterator1, class InputIterator2, class T>
|
| 5079 |
-
T inner_product(InputIterator1 first1, InputIterator1 last1,
|
| 5080 |
-
InputIterator2 first2, T init);
|
| 5081 |
-
template <class InputIterator1, class InputIterator2, class T,
|
| 5082 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5083 |
-
T inner_product(InputIterator1 first1, InputIterator1 last1,
|
| 5084 |
-
InputIterator2 first2, T init,
|
| 5085 |
-
BinaryOperation1 binary_op1,
|
| 5086 |
-
BinaryOperation2 binary_op2);
|
| 5087 |
-
|
| 5088 |
-
// [transform.reduce], transform reduce
|
| 5089 |
-
template<class InputIterator1, class InputIterator2, class T>
|
| 5090 |
-
T transform_reduce(InputIterator1 first1, InputIterator1 last1,
|
| 5091 |
-
InputIterator2 first2,
|
| 5092 |
-
T init);
|
| 5093 |
-
template<class InputIterator1, class InputIterator2, class T,
|
| 5094 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5095 |
-
T transform_reduce(InputIterator1 first1, InputIterator1 last1,
|
| 5096 |
-
InputIterator2 first2,
|
| 5097 |
-
T init,
|
| 5098 |
-
BinaryOperation1 binary_op1,
|
| 5099 |
-
BinaryOperation2 binary_op2);
|
| 5100 |
-
template<class InputIterator, class T,
|
| 5101 |
-
class BinaryOperation, class UnaryOperation>
|
| 5102 |
-
T transform_reduce(InputIterator first, InputIterator last,
|
| 5103 |
-
T init,
|
| 5104 |
-
BinaryOperation binary_op, UnaryOperation unary_op);
|
| 5105 |
-
template<class ExecutionPolicy,
|
| 5106 |
-
class ForwardIterator1, class ForwardIterator2, class T>
|
| 5107 |
-
T transform_reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5108 |
-
ForwardIterator1 first1, ForwardIterator1 last1,
|
| 5109 |
-
ForwardIterator2 first2,
|
| 5110 |
-
T init);
|
| 5111 |
-
template<class ExecutionPolicy,
|
| 5112 |
-
class ForwardIterator1, class ForwardIterator2, class T,
|
| 5113 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5114 |
-
T transform_reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5115 |
-
ForwardIterator1 first1, ForwardIterator1 last1,
|
| 5116 |
-
ForwardIterator2 first2,
|
| 5117 |
-
T init,
|
| 5118 |
-
BinaryOperation1 binary_op1,
|
| 5119 |
-
BinaryOperation2 binary_op2);
|
| 5120 |
-
template<class ExecutionPolicy,
|
| 5121 |
-
class ForwardIterator, class T,
|
| 5122 |
-
class BinaryOperation, class UnaryOperation>
|
| 5123 |
-
T transform_reduce(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5124 |
-
ForwardIterator first, ForwardIterator last,
|
| 5125 |
-
T init,
|
| 5126 |
-
BinaryOperation binary_op, UnaryOperation unary_op);
|
| 5127 |
-
|
| 5128 |
-
// [partial.sum], partial sum
|
| 5129 |
-
template <class InputIterator, class OutputIterator>
|
| 5130 |
-
OutputIterator partial_sum(InputIterator first,
|
| 5131 |
-
InputIterator last,
|
| 5132 |
-
OutputIterator result);
|
| 5133 |
-
template <class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5134 |
-
OutputIterator partial_sum(InputIterator first,
|
| 5135 |
-
InputIterator last,
|
| 5136 |
-
OutputIterator result,
|
| 5137 |
-
BinaryOperation binary_op);
|
| 5138 |
-
|
| 5139 |
-
// [exclusive.scan], exclusive scan
|
| 5140 |
-
template<class InputIterator, class OutputIterator, class T>
|
| 5141 |
-
OutputIterator exclusive_scan(InputIterator first, InputIterator last,
|
| 5142 |
-
OutputIterator result,
|
| 5143 |
-
T init);
|
| 5144 |
-
template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
|
| 5145 |
-
OutputIterator exclusive_scan(InputIterator first, InputIterator last,
|
| 5146 |
-
OutputIterator result,
|
| 5147 |
-
T init, BinaryOperation binary_op);
|
| 5148 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class T>
|
| 5149 |
-
ForwardIterator2 exclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5150 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5151 |
-
ForwardIterator2 result,
|
| 5152 |
-
T init);
|
| 5153 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class T,
|
| 5154 |
-
class BinaryOperation>
|
| 5155 |
-
ForwardIterator2 exclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5156 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5157 |
-
ForwardIterator2 result,
|
| 5158 |
-
T init, BinaryOperation binary_op);
|
| 5159 |
-
|
| 5160 |
-
// [inclusive.scan], inclusive scan
|
| 5161 |
-
template<class InputIterator, class OutputIterator>
|
| 5162 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5163 |
-
OutputIterator result);
|
| 5164 |
-
template<class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5165 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5166 |
-
OutputIterator result,
|
| 5167 |
-
BinaryOperation binary_op);
|
| 5168 |
-
template<class InputIterator, class OutputIterator, class BinaryOperation, class T>
|
| 5169 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5170 |
-
OutputIterator result,
|
| 5171 |
-
BinaryOperation binary_op, T init);
|
| 5172 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
|
| 5173 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5174 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5175 |
-
ForwardIterator2 result);
|
| 5176 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
|
| 5177 |
-
class BinaryOperation>
|
| 5178 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5179 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5180 |
-
ForwardIterator2 result,
|
| 5181 |
-
BinaryOperation binary_op);
|
| 5182 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
|
| 5183 |
-
class BinaryOperation, class T>
|
| 5184 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5185 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5186 |
-
ForwardIterator2 result,
|
| 5187 |
-
BinaryOperation binary_op, T init);
|
| 5188 |
-
|
| 5189 |
-
// [transform.exclusive.scan], transform exclusive scan
|
| 5190 |
-
template<class InputIterator, class OutputIterator, class T,
|
| 5191 |
-
class BinaryOperation, class UnaryOperation>
|
| 5192 |
-
OutputIterator transform_exclusive_scan(InputIterator first, InputIterator last,
|
| 5193 |
-
OutputIterator result,
|
| 5194 |
-
T init,
|
| 5195 |
-
BinaryOperation binary_op,
|
| 5196 |
-
UnaryOperation unary_op);
|
| 5197 |
-
template<class ExecutionPolicy,
|
| 5198 |
-
class ForwardIterator1, class ForwardIterator2, class T,
|
| 5199 |
-
class BinaryOperation, class UnaryOperation>
|
| 5200 |
-
ForwardIterator2 transform_exclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5201 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5202 |
-
ForwardIterator2 result,
|
| 5203 |
-
T init,
|
| 5204 |
-
BinaryOperation binary_op,
|
| 5205 |
-
UnaryOperation unary_op);
|
| 5206 |
-
|
| 5207 |
-
// [transform.inclusive.scan], transform inclusive scan
|
| 5208 |
-
template<class InputIterator, class OutputIterator,
|
| 5209 |
-
class BinaryOperation, class UnaryOperation>
|
| 5210 |
-
OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
|
| 5211 |
-
OutputIterator result,
|
| 5212 |
-
BinaryOperation binary_op,
|
| 5213 |
-
UnaryOperation unary_op);
|
| 5214 |
-
template<class InputIterator, class OutputIterator,
|
| 5215 |
-
class BinaryOperation, class UnaryOperation, class T>
|
| 5216 |
-
OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
|
| 5217 |
-
OutputIterator result,
|
| 5218 |
-
BinaryOperation binary_op,
|
| 5219 |
-
UnaryOperation unary_op,
|
| 5220 |
-
T init);
|
| 5221 |
-
template<class ExecutionPolicy,
|
| 5222 |
-
class ForwardIterator1, class ForwardIterator2,
|
| 5223 |
-
class BinaryOperation, class UnaryOperation>
|
| 5224 |
-
ForwardIterator2 transform_inclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5225 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5226 |
-
ForwardIterator2 result,
|
| 5227 |
-
BinaryOperation binary_op,
|
| 5228 |
-
UnaryOperation unary_op);
|
| 5229 |
-
template<class ExecutionPolicy,
|
| 5230 |
-
class ForwardIterator1, class ForwardIterator2,
|
| 5231 |
-
class BinaryOperation, class UnaryOperation, class T>
|
| 5232 |
-
ForwardIterator2 transform_inclusive_scan(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5233 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5234 |
-
ForwardIterator2 result,
|
| 5235 |
-
BinaryOperation binary_op,
|
| 5236 |
-
UnaryOperation unary_op,
|
| 5237 |
-
T init);
|
| 5238 |
-
|
| 5239 |
-
// [adjacent.difference], adjacent difference
|
| 5240 |
-
template <class InputIterator, class OutputIterator>
|
| 5241 |
-
OutputIterator adjacent_difference(InputIterator first,
|
| 5242 |
-
InputIterator last,
|
| 5243 |
-
OutputIterator result);
|
| 5244 |
-
template <class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5245 |
-
OutputIterator adjacent_difference(InputIterator first,
|
| 5246 |
-
InputIterator last,
|
| 5247 |
-
OutputIterator result,
|
| 5248 |
-
BinaryOperation binary_op);
|
| 5249 |
-
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
|
| 5250 |
-
ForwardIterator2 adjacent_difference(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5251 |
-
ForwardIterator1 first,
|
| 5252 |
-
ForwardIterator1 last,
|
| 5253 |
-
ForwardIterator2 result);
|
| 5254 |
-
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
|
| 5255 |
-
class BinaryOperation>
|
| 5256 |
-
ForwardIterator2 adjacent_difference(ExecutionPolicy&& exec, // see [algorithms.parallel.overloads]
|
| 5257 |
-
ForwardIterator1 first,
|
| 5258 |
-
ForwardIterator1 last,
|
| 5259 |
-
ForwardIterator2 result,
|
| 5260 |
-
BinaryOperation binary_op);
|
| 5261 |
-
|
| 5262 |
-
// [numeric.iota], iota
|
| 5263 |
-
template <class ForwardIterator, class T>
|
| 5264 |
-
void iota(ForwardIterator first, ForwardIterator last, T value);
|
| 5265 |
-
|
| 5266 |
-
// [numeric.ops.gcd], greatest common divisor
|
| 5267 |
-
template <class M, class N>
|
| 5268 |
-
constexpr common_type_t<M,N> gcd(M m, N n);
|
| 5269 |
-
|
| 5270 |
-
// [numeric.ops.lcm], least common multiple
|
| 5271 |
-
template <class M, class N>
|
| 5272 |
-
constexpr common_type_t<M,N> lcm(M m, N n);
|
| 5273 |
-
}
|
| 5274 |
-
```
|
| 5275 |
-
|
| 5276 |
-
The requirements on the types of algorithms’ arguments that are
|
| 5277 |
-
described in the introduction to Clause [[algorithms]] also apply to
|
| 5278 |
-
the following algorithms.
|
| 5279 |
-
|
| 5280 |
-
Throughout this subclause, the parameters `UnaryOperation`,
|
| 5281 |
-
`BinaryOperation`, `BinaryOperation1`, and `BinaryOperation2` are used
|
| 5282 |
-
whenever an algorithm expects a function object ([[function.objects]]).
|
| 5283 |
-
|
| 5284 |
-
[*Note 1*: The use of closed ranges as well as semi-open ranges to
|
| 5285 |
-
specify requirements throughout this subclause is
|
| 5286 |
-
intentional. — *end note*]
|
| 5287 |
-
|
| 5288 |
-
### Accumulate <a id="accumulate">[[accumulate]]</a>
|
| 5289 |
-
|
| 5290 |
-
``` cpp
|
| 5291 |
-
template <class InputIterator, class T>
|
| 5292 |
-
T accumulate(InputIterator first, InputIterator last, T init);
|
| 5293 |
-
template <class InputIterator, class T, class BinaryOperation>
|
| 5294 |
-
T accumulate(InputIterator first, InputIterator last, T init,
|
| 5295 |
-
BinaryOperation binary_op);
|
| 5296 |
-
```
|
| 5297 |
-
|
| 5298 |
-
*Requires:* `T` shall meet the requirements of `CopyConstructible`
|
| 5299 |
-
(Table [[tab:copyconstructible]]) and `CopyAssignable`
|
| 5300 |
-
(Table [[tab:copyassignable]]) types. In the range \[`first`, `last`\],
|
| 5301 |
-
`binary_op` shall neither modify elements nor invalidate iterators or
|
| 5302 |
-
subranges.[^13]
|
| 5303 |
-
|
| 5304 |
-
*Effects:* Computes its result by initializing the accumulator `acc`
|
| 5305 |
-
with the initial value `init` and then modifies it with `acc = acc + *i`
|
| 5306 |
-
or `acc = binary_op(acc, *i)` for every iterator `i` in the range
|
| 5307 |
-
\[`first`, `last`) in order.[^14]
|
| 5308 |
-
|
| 5309 |
-
### Reduce <a id="reduce">[[reduce]]</a>
|
| 5310 |
-
|
| 5311 |
-
``` cpp
|
| 5312 |
-
template<class InputIterator>
|
| 5313 |
-
typename iterator_traits<InputIterator>::value_type
|
| 5314 |
-
reduce(InputIterator first, InputIterator last);
|
| 5315 |
-
```
|
| 5316 |
-
|
| 5317 |
-
*Effects:* Equivalent to:
|
| 5318 |
-
|
| 5319 |
-
``` cpp
|
| 5320 |
-
return reduce(first, last,
|
| 5321 |
-
typename iterator_traits<InputIterator>::value_type{});
|
| 5322 |
-
```
|
| 5323 |
-
|
| 5324 |
-
``` cpp
|
| 5325 |
-
template<class ExecutionPolicy, class ForwardIterator>
|
| 5326 |
-
typename iterator_traits<ForwardIterator>::value_type
|
| 5327 |
-
reduce(ExecutionPolicy&& exec,
|
| 5328 |
-
ForwardIterator first, ForwardIterator last);
|
| 5329 |
-
```
|
| 5330 |
-
|
| 5331 |
-
*Effects:* Equivalent to:
|
| 5332 |
-
|
| 5333 |
-
``` cpp
|
| 5334 |
-
return reduce(std::forward<ExecutionPolicy>(exec), first, last,
|
| 5335 |
-
typename iterator_traits<ForwardIterator>::value_type{});
|
| 5336 |
-
```
|
| 5337 |
-
|
| 5338 |
-
``` cpp
|
| 5339 |
-
template<class InputIterator, class T>
|
| 5340 |
-
T reduce(InputIterator first, InputIterator last, T init);
|
| 5341 |
-
```
|
| 5342 |
-
|
| 5343 |
-
*Effects:* Equivalent to:
|
| 5344 |
-
|
| 5345 |
-
``` cpp
|
| 5346 |
-
return reduce(first, last, init, plus<>());
|
| 5347 |
-
```
|
| 5348 |
-
|
| 5349 |
-
``` cpp
|
| 5350 |
-
template<class ExecutionPolicy, class ForwardIterator, class T>
|
| 5351 |
-
T reduce(ExecutionPolicy&& exec,
|
| 5352 |
-
ForwardIterator first, ForwardIterator last, T init);
|
| 5353 |
-
```
|
| 5354 |
-
|
| 5355 |
-
*Effects:* Equivalent to:
|
| 5356 |
-
|
| 5357 |
-
``` cpp
|
| 5358 |
-
return reduce(std::forward<ExecutionPolicy>(exec), first, last, init, plus<>());
|
| 5359 |
-
```
|
| 5360 |
-
|
| 5361 |
-
``` cpp
|
| 5362 |
-
template<class InputIterator, class T, class BinaryOperation>
|
| 5363 |
-
T reduce(InputIterator first, InputIterator last, T init,
|
| 5364 |
-
BinaryOperation binary_op);
|
| 5365 |
-
template<class ExecutionPolicy, class ForwardIterator, class T, class BinaryOperation>
|
| 5366 |
-
T reduce(ExecutionPolicy&& exec,
|
| 5367 |
-
ForwardIterator first, ForwardIterator last, T init,
|
| 5368 |
-
BinaryOperation binary_op);
|
| 5369 |
-
```
|
| 5370 |
-
|
| 5371 |
-
*Requires:*
|
| 5372 |
-
|
| 5373 |
-
- `T` shall be `MoveConstructible` (Table [[tab:moveconstructible]]).
|
| 5374 |
-
- All of `binary_op(init, *first)`, `binary_op(*first, init)`,
|
| 5375 |
-
`binary_op(init, init)`, and `binary_op(*first, *first)` shall be
|
| 5376 |
-
convertible to `T`.
|
| 5377 |
-
- `binary_op` shall neither invalidate iterators or subranges, nor
|
| 5378 |
-
modify elements in the range \[`first`, `last`\].
|
| 5379 |
-
|
| 5380 |
-
*Returns:* *GENERALIZED_SUM*(binary_op, init, \*i, ...) for every `i` in
|
| 5381 |
-
\[`first`, `last`).
|
| 5382 |
-
|
| 5383 |
-
*Complexity:* 𝑂(`last - first`) applications of `binary_op`.
|
| 5384 |
-
|
| 5385 |
-
[*Note 1*: The difference between `reduce` and `accumulate` is that
|
| 5386 |
-
`reduce` applies `binary_op` in an unspecified order, which yields a
|
| 5387 |
-
nondeterministic result for non-associative or non-commutative
|
| 5388 |
-
`binary_op` such as floating-point addition. — *end note*]
|
| 5389 |
-
|
| 5390 |
-
### Inner product <a id="inner.product">[[inner.product]]</a>
|
| 5391 |
-
|
| 5392 |
-
``` cpp
|
| 5393 |
-
template <class InputIterator1, class InputIterator2, class T>
|
| 5394 |
-
T inner_product(InputIterator1 first1, InputIterator1 last1,
|
| 5395 |
-
InputIterator2 first2, T init);
|
| 5396 |
-
template <class InputIterator1, class InputIterator2, class T,
|
| 5397 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5398 |
-
T inner_product(InputIterator1 first1, InputIterator1 last1,
|
| 5399 |
-
InputIterator2 first2, T init,
|
| 5400 |
-
BinaryOperation1 binary_op1,
|
| 5401 |
-
BinaryOperation2 binary_op2);
|
| 5402 |
-
```
|
| 5403 |
-
|
| 5404 |
-
*Requires:* `T` shall meet the requirements of `CopyConstructible`
|
| 5405 |
-
(Table [[tab:copyconstructible]]) and `CopyAssignable`
|
| 5406 |
-
(Table [[tab:copyassignable]]) types. In the ranges \[`first1`,
|
| 5407 |
-
`last1`\] and \[`first2`, `first2 + (last1 - first1)`\] `binary_op1` and
|
| 5408 |
-
`binary_op2` shall neither modify elements nor invalidate iterators or
|
| 5409 |
-
subranges.[^15]
|
| 5410 |
-
|
| 5411 |
-
*Effects:* Computes its result by initializing the accumulator `acc`
|
| 5412 |
-
with the initial value `init` and then modifying it with
|
| 5413 |
-
`acc = acc + (*i1) * (*i2)` or
|
| 5414 |
-
`acc = binary_op1(acc, binary_op2(*i1, *i2))` for every iterator `i1` in
|
| 5415 |
-
the range \[`first1`, `last1`) and iterator `i2` in the range
|
| 5416 |
-
\[`first2`, `first2 + (last1 - first1)`) in order.
|
| 5417 |
-
|
| 5418 |
-
### Transform reduce <a id="transform.reduce">[[transform.reduce]]</a>
|
| 5419 |
-
|
| 5420 |
-
``` cpp
|
| 5421 |
-
template <class InputIterator1, class InputIterator2, class T>
|
| 5422 |
-
T transform_reduce(InputIterator1 first1, InputIterator1 last1,
|
| 5423 |
-
InputIterator2 first2,
|
| 5424 |
-
T init);
|
| 5425 |
-
template <class ExecutionPolicy,
|
| 5426 |
-
class ForwardIterator1, class ForwardIterator2, class T>
|
| 5427 |
-
T transform_reduce(ExecutionPolicy&& exec,
|
| 5428 |
-
ForwardIterator1 first1, ForwardIterator1 last1,
|
| 5429 |
-
ForwardIterator2 first2,
|
| 5430 |
-
T init);
|
| 5431 |
-
```
|
| 5432 |
-
|
| 5433 |
-
*Effects:* Equivalent to:
|
| 5434 |
-
|
| 5435 |
-
``` cpp
|
| 5436 |
-
return transform_reduce(first1, last1, first2, init, plus<>(), multiplies<>());
|
| 5437 |
-
```
|
| 5438 |
-
|
| 5439 |
-
``` cpp
|
| 5440 |
-
template <class InputIterator1, class InputIterator2, class T,
|
| 5441 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5442 |
-
T transform_reduce(InputIterator1 first1, InputIterator1 last1,
|
| 5443 |
-
InputIterator2 first2,
|
| 5444 |
-
T init,
|
| 5445 |
-
BinaryOperation1 binary_op1,
|
| 5446 |
-
BinaryOperation2 binary_op2);
|
| 5447 |
-
template <class ExecutionPolicy,
|
| 5448 |
-
class ForwardIterator1, class ForwardIterator2, class T,
|
| 5449 |
-
class BinaryOperation1, class BinaryOperation2>
|
| 5450 |
-
T transform_reduce(ExecutionPolicy&& exec,
|
| 5451 |
-
ForwardIterator1 first1, ForwardIterator1 last1,
|
| 5452 |
-
ForwardIterator2 first2,
|
| 5453 |
-
T init,
|
| 5454 |
-
BinaryOperation1 binary_op1,
|
| 5455 |
-
BinaryOperation2 binary_op2);
|
| 5456 |
-
```
|
| 5457 |
-
|
| 5458 |
-
*Requires:*
|
| 5459 |
-
|
| 5460 |
-
- `T` shall be `MoveConstructible` (Table [[tab:moveconstructible]]).
|
| 5461 |
-
- All of
|
| 5462 |
-
- `binary_op1(init, init)`,
|
| 5463 |
-
- `binary_op1(init, binary_op2(*first1, *first2))`,
|
| 5464 |
-
- `binary_op1(binary_op2(*first1, *first2), init)`, and
|
| 5465 |
-
- `binary_op1(binary_op2(*first1, *first2), binary_op2(*first1, *first2))`
|
| 5466 |
-
|
| 5467 |
-
shall be convertible to `T`.
|
| 5468 |
-
- Neither `binary_op1` nor `binary_op2` shall invalidate subranges, or
|
| 5469 |
-
modify elements in the ranges \[`first1`, `last1`\] and \[`first2`,
|
| 5470 |
-
`first2 + (last1 - first1)`\].
|
| 5471 |
-
|
| 5472 |
-
*Returns:*
|
| 5473 |
-
|
| 5474 |
-
``` cpp
|
| 5475 |
-
GENERALIZED_SUM(binary_op1, init, binary_op2(*i, *(first2 + (i - first1))), ...)
|
| 5476 |
-
```
|
| 5477 |
-
|
| 5478 |
-
for every iterator `i` in \[`first1`, `last1`).
|
| 5479 |
-
|
| 5480 |
-
*Complexity:* 𝑂(`last1 - first1`) applications each of `binary_op1` and
|
| 5481 |
-
`binary_op2`.
|
| 5482 |
-
|
| 5483 |
-
``` cpp
|
| 5484 |
-
template<class InputIterator, class T,
|
| 5485 |
-
class BinaryOperation, class UnaryOperation>
|
| 5486 |
-
T transform_reduce(InputIterator first, InputIterator last, T init,
|
| 5487 |
-
BinaryOperation binary_op, UnaryOperation unary_op);
|
| 5488 |
-
template<class ExecutionPolicy,
|
| 5489 |
-
class ForwardIterator, class T,
|
| 5490 |
-
class BinaryOperation, class UnaryOperation>
|
| 5491 |
-
T transform_reduce(ExecutionPolicy&& exec,
|
| 5492 |
-
ForwardIterator first, ForwardIterator last,
|
| 5493 |
-
T init, BinaryOperation binary_op, UnaryOperation unary_op);
|
| 5494 |
-
```
|
| 5495 |
-
|
| 5496 |
-
*Requires:*
|
| 5497 |
-
|
| 5498 |
-
- `T` shall be `MoveConstructible` (Table [[tab:moveconstructible]]).
|
| 5499 |
-
- All of
|
| 5500 |
-
- `binary_op(init, init)`,
|
| 5501 |
-
- `binary_op(init, unary_op(*first))`,
|
| 5502 |
-
- `binary_op(unary_op(*first), init)`, and
|
| 5503 |
-
- `binary_op(unary_op(*first), unary_op(*first))`
|
| 5504 |
-
|
| 5505 |
-
shall be convertible to `T`.
|
| 5506 |
-
- Neither `unary_op` nor `binary_op` shall invalidate subranges, or
|
| 5507 |
-
modify elements in the range \[`first`, `last`\].
|
| 5508 |
-
|
| 5509 |
-
*Returns:*
|
| 5510 |
-
|
| 5511 |
-
``` cpp
|
| 5512 |
-
GENERALIZED_SUM(binary_op, init, unary_op(*i), ...)
|
| 5513 |
-
```
|
| 5514 |
-
|
| 5515 |
-
for every iterator `i` in \[`first`, `last`).
|
| 5516 |
-
|
| 5517 |
-
*Complexity:* 𝑂(`last - first`) applications each of `unary_op` and
|
| 5518 |
-
`binary_op`.
|
| 5519 |
-
|
| 5520 |
-
[*Note 1*: `transform_reduce` does not apply `unary_op` to
|
| 5521 |
-
`init`. — *end note*]
|
| 5522 |
-
|
| 5523 |
-
### Partial sum <a id="partial.sum">[[partial.sum]]</a>
|
| 5524 |
-
|
| 5525 |
-
``` cpp
|
| 5526 |
-
template <class InputIterator, class OutputIterator>
|
| 5527 |
-
OutputIterator partial_sum(
|
| 5528 |
-
InputIterator first, InputIterator last,
|
| 5529 |
-
OutputIterator result);
|
| 5530 |
-
template <class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5531 |
-
OutputIterator partial_sum(
|
| 5532 |
-
InputIterator first, InputIterator last,
|
| 5533 |
-
OutputIterator result, BinaryOperation binary_op);
|
| 5534 |
-
```
|
| 5535 |
-
|
| 5536 |
-
*Requires:* `InputIterator`’s value type shall be constructible from the
|
| 5537 |
-
type of `*first`. The result of the expression `acc + *i` or
|
| 5538 |
-
`binary_op(acc, *i)` shall be implicitly convertible to
|
| 5539 |
-
`InputIterator`’s value type. `acc` shall be
|
| 5540 |
-
writable ([[iterator.requirements.general]]) to the `result` output
|
| 5541 |
-
iterator. In the ranges \[`first`, `last`\] and \[`result`,
|
| 5542 |
-
`result + (last - first)`\] `binary_op` shall neither modify elements
|
| 5543 |
-
nor invalidate iterators or subranges.[^16]
|
| 5544 |
-
|
| 5545 |
-
*Effects:* For a non-empty range, the function creates an accumulator
|
| 5546 |
-
`acc` whose type is `InputIterator`’s value type, initializes it with
|
| 5547 |
-
`*first`, and assigns the result to `*result`. For every iterator `i` in
|
| 5548 |
-
\[`first + 1`, `last`) in order, `acc` is then modified by
|
| 5549 |
-
`acc = acc + *i` or `acc = binary_op(acc, *i)` and the result is
|
| 5550 |
-
assigned to `*(result + (i - first))`.
|
| 5551 |
-
|
| 5552 |
-
*Returns:* `result + (last - first)`.
|
| 5553 |
-
|
| 5554 |
-
*Complexity:* Exactly `(last - first) - 1` applications of the binary
|
| 5555 |
-
operation.
|
| 5556 |
-
|
| 5557 |
-
*Remarks:* `result` may be equal to `first`.
|
| 5558 |
-
|
| 5559 |
-
### Exclusive scan <a id="exclusive.scan">[[exclusive.scan]]</a>
|
| 5560 |
-
|
| 5561 |
-
``` cpp
|
| 5562 |
-
template<class InputIterator, class OutputIterator, class T>
|
| 5563 |
-
OutputIterator exclusive_scan(InputIterator first, InputIterator last,
|
| 5564 |
-
OutputIterator result,
|
| 5565 |
-
T init);
|
| 5566 |
-
```
|
| 5567 |
-
|
| 5568 |
-
*Effects:* Equivalent to:
|
| 5569 |
-
|
| 5570 |
-
``` cpp
|
| 5571 |
-
return exclusive_scan(first, last, result, init, plus<>());
|
| 5572 |
-
```
|
| 5573 |
-
|
| 5574 |
-
``` cpp
|
| 5575 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2, class T>
|
| 5576 |
-
ForwardIterator2 exclusive_scan(ExecutionPolicy&& exec,
|
| 5577 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5578 |
-
ForwardIterator2 result,
|
| 5579 |
-
T init);
|
| 5580 |
-
```
|
| 5581 |
-
|
| 5582 |
-
*Effects:* Equivalent to:
|
| 5583 |
-
|
| 5584 |
-
``` cpp
|
| 5585 |
-
return exclusive_scan(std::forward<ExecutionPolicy>(exec),
|
| 5586 |
-
first, last, result, init, plus<>());
|
| 5587 |
-
```
|
| 5588 |
-
|
| 5589 |
-
``` cpp
|
| 5590 |
-
template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
|
| 5591 |
-
OutputIterator exclusive_scan(InputIterator first, InputIterator last,
|
| 5592 |
-
OutputIterator result,
|
| 5593 |
-
T init, BinaryOperation binary_op);
|
| 5594 |
-
template<class ExecutionPolicy,
|
| 5595 |
-
class ForwardIterator1, class ForwardIterator2, class T, class BinaryOperation>
|
| 5596 |
-
ForwardIterator2 exclusive_scan(ExecutionPolicy&& exec,
|
| 5597 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5598 |
-
ForwardIterator2 result,
|
| 5599 |
-
T init, BinaryOperation binary_op);
|
| 5600 |
-
```
|
| 5601 |
-
|
| 5602 |
-
*Requires:*
|
| 5603 |
-
|
| 5604 |
-
- `T` shall be `MoveConstructible` (Table [[tab:moveconstructible]]).
|
| 5605 |
-
- All of `binary_op(init, init)`, `binary_op(init, *first)`, and
|
| 5606 |
-
`binary_op(*first, *first)` shall be convertible to `T`.
|
| 5607 |
-
- `binary_op` shall neither invalidate iterators or subranges, nor
|
| 5608 |
-
modify elements in the ranges \[`first`, `last`\] or \[`result`,
|
| 5609 |
-
`result + (last - first)`\].
|
| 5610 |
-
|
| 5611 |
-
*Effects:* For each integer `K` in \[`0`, `last - first`) assigns
|
| 5612 |
-
through `result + K` the value of:
|
| 5613 |
-
|
| 5614 |
-
``` cpp
|
| 5615 |
-
GENERALIZED_NONCOMMUTATIVE_SUM(
|
| 5616 |
-
binary_op, init, *(first + 0), *(first + 1), ..., *(first + K - 1))
|
| 5617 |
-
```
|
| 5618 |
-
|
| 5619 |
-
*Returns:* The end of the resulting range beginning at `result`.
|
| 5620 |
-
|
| 5621 |
-
*Complexity:* 𝑂(`last - first`) applications of `binary_op`.
|
| 5622 |
-
|
| 5623 |
-
*Remarks:* `result` may be equal to `first`.
|
| 5624 |
-
|
| 5625 |
-
[*Note 1*: The difference between `exclusive_scan` and `inclusive_scan`
|
| 5626 |
-
is that `exclusive_scan` excludes the `i`th input element from the `i`th
|
| 5627 |
-
sum. If `binary_op` is not mathematically associative, the behavior of
|
| 5628 |
-
`exclusive_scan` may be nondeterministic. — *end note*]
|
| 5629 |
-
|
| 5630 |
-
### Inclusive scan <a id="inclusive.scan">[[inclusive.scan]]</a>
|
| 5631 |
-
|
| 5632 |
-
``` cpp
|
| 5633 |
-
template<class InputIterator, class OutputIterator>
|
| 5634 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5635 |
-
OutputIterator result);
|
| 5636 |
-
```
|
| 5637 |
-
|
| 5638 |
-
*Effects:* Equivalent to:
|
| 5639 |
-
|
| 5640 |
-
``` cpp
|
| 5641 |
-
return inclusive_scan(first, last, result, plus<>());
|
| 5642 |
-
```
|
| 5643 |
-
|
| 5644 |
-
``` cpp
|
| 5645 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
|
| 5646 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec,
|
| 5647 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5648 |
-
ForwardIterator2 result);
|
| 5649 |
-
```
|
| 5650 |
-
|
| 5651 |
-
*Effects:* Equivalent to:
|
| 5652 |
-
|
| 5653 |
-
``` cpp
|
| 5654 |
-
return inclusive_scan(std::forward<ExecutionPolicy>(exec), first, last, result, plus<>());
|
| 5655 |
-
```
|
| 5656 |
-
|
| 5657 |
-
``` cpp
|
| 5658 |
-
template<class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5659 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5660 |
-
OutputIterator result,
|
| 5661 |
-
BinaryOperation binary_op);
|
| 5662 |
-
template<class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
|
| 5663 |
-
class BinaryOperation>
|
| 5664 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec,
|
| 5665 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5666 |
-
ForwardIterator2 result,
|
| 5667 |
-
BinaryOperation binary_op);
|
| 5668 |
-
|
| 5669 |
-
template<class InputIterator, class OutputIterator, class BinaryOperation, class T>
|
| 5670 |
-
OutputIterator inclusive_scan(InputIterator first, InputIterator last,
|
| 5671 |
-
OutputIterator result,
|
| 5672 |
-
BinaryOperation binary_op, T init);
|
| 5673 |
-
template<class ExecutionPolicy,
|
| 5674 |
-
class ForwardIterator1, class ForwardIterator2, class BinaryOperation, class T>
|
| 5675 |
-
ForwardIterator2 inclusive_scan(ExecutionPolicy&& exec,
|
| 5676 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5677 |
-
ForwardIterator2 result,
|
| 5678 |
-
BinaryOperation binary_op, T init);
|
| 5679 |
-
```
|
| 5680 |
-
|
| 5681 |
-
*Requires:*
|
| 5682 |
-
|
| 5683 |
-
- If `init` is provided, `T` shall be `MoveConstructible`
|
| 5684 |
-
(Table [[tab:moveconstructible]]); otherwise, `ForwardIterator1`’s
|
| 5685 |
-
value type shall be `MoveConstructible`.
|
| 5686 |
-
- If `init` is provided, all of `binary_op(init, init)`,
|
| 5687 |
-
`binary_op(init, *first)`, and `binary_op(*first, *first)` shall be
|
| 5688 |
-
convertible to `T`; otherwise, `binary_op(*first, *first)` shall be
|
| 5689 |
-
convertible to `ForwardIterator1`’s value type.
|
| 5690 |
-
- `binary_op` shall neither invalidate iterators or subranges, nor
|
| 5691 |
-
modify elements in the ranges \[`first`, `last`\] or \[`result`,
|
| 5692 |
-
`result + (last - first)`\].
|
| 5693 |
-
|
| 5694 |
-
*Effects:* For each integer `K` in \[`0`, `last - first`) assigns
|
| 5695 |
-
through `result + K` the value of
|
| 5696 |
-
|
| 5697 |
-
- *GENERALIZED_NONCOMMUTATIVE_SUM*(
|
| 5698 |
-
binary_op, init, \*(first + 0), \*(first + 1), ..., \*(first +
|
| 5699 |
-
K))
|
| 5700 |
-
if `init` is provided, or
|
| 5701 |
-
- *GENERALIZED_NONCOMMUTATIVE_SUM*(
|
| 5702 |
-
binary_op, \*(first + 0), \*(first + 1), ..., \*(first + K))
|
| 5703 |
-
otherwise.
|
| 5704 |
-
|
| 5705 |
-
*Returns:* The end of the resulting range beginning at `result`.
|
| 5706 |
-
|
| 5707 |
-
*Complexity:* 𝑂(`last - first`) applications of `binary_op`.
|
| 5708 |
-
|
| 5709 |
-
*Remarks:* `result` may be equal to `first`.
|
| 5710 |
-
|
| 5711 |
-
[*Note 1*: The difference between `exclusive_scan` and `inclusive_scan`
|
| 5712 |
-
is that `inclusive_scan` includes the `i`th input element in the `i`th
|
| 5713 |
-
sum. If `binary_op` is not mathematically associative, the behavior of
|
| 5714 |
-
`inclusive_scan` may be nondeterministic. — *end note*]
|
| 5715 |
-
|
| 5716 |
-
### Transform exclusive scan <a id="transform.exclusive.scan">[[transform.exclusive.scan]]</a>
|
| 5717 |
-
|
| 5718 |
-
``` cpp
|
| 5719 |
-
template<class InputIterator, class OutputIterator, class T,
|
| 5720 |
-
class BinaryOperation, class UnaryOperation>
|
| 5721 |
-
OutputIterator transform_exclusive_scan(InputIterator first, InputIterator last,
|
| 5722 |
-
OutputIterator result,
|
| 5723 |
-
T init,
|
| 5724 |
-
BinaryOperation binary_op,
|
| 5725 |
-
UnaryOperation unary_op);
|
| 5726 |
-
template<class ExecutionPolicy,
|
| 5727 |
-
class ForwardIterator1, class ForwardIterator2, class T,
|
| 5728 |
-
class BinaryOperation, class UnaryOperation>
|
| 5729 |
-
ForwardIterator2 transform_exclusive_scan(ExecutionPolicy&& exec,
|
| 5730 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5731 |
-
ForwardIterator2 result,
|
| 5732 |
-
T init,
|
| 5733 |
-
BinaryOperation binary_op,
|
| 5734 |
-
UnaryOperation unary_op);
|
| 5735 |
-
```
|
| 5736 |
-
|
| 5737 |
-
*Requires:*
|
| 5738 |
-
|
| 5739 |
-
- `T` shall be `MoveConstructible` (Table [[tab:moveconstructible]]).
|
| 5740 |
-
- All of
|
| 5741 |
-
- `binary_op(init, init)`,
|
| 5742 |
-
- `binary_op(init, unary_op(*first))`, and
|
| 5743 |
-
- `binary_op(unary_op(*first), unary_op(*first))`
|
| 5744 |
-
|
| 5745 |
-
shall be convertible to `T`.
|
| 5746 |
-
- Neither `unary_op` nor `binary_op` shall invalidate iterators or
|
| 5747 |
-
subranges, or modify elements in the ranges \[`first`, `last`\] or
|
| 5748 |
-
\[`result`, `result + (last - first)`\].
|
| 5749 |
-
|
| 5750 |
-
*Effects:* For each integer `K` in \[`0`, `last - first`) assigns
|
| 5751 |
-
through `result + K` the value of:
|
| 5752 |
-
|
| 5753 |
-
``` cpp
|
| 5754 |
-
GENERALIZED_NONCOMMUTATIVE_SUM(
|
| 5755 |
-
binary_op, init,
|
| 5756 |
-
unary_op(*(first + 0)), unary_op(*(first + 1)), ..., unary_op(*(first + K - 1)))
|
| 5757 |
-
```
|
| 5758 |
-
|
| 5759 |
-
*Returns:* The end of the resulting range beginning at `result`.
|
| 5760 |
-
|
| 5761 |
-
*Complexity:* 𝑂(`last - first`) applications each of `unary_op` and
|
| 5762 |
-
`binary_op`.
|
| 5763 |
-
|
| 5764 |
-
*Remarks:* `result` may be equal to `first`.
|
| 5765 |
-
|
| 5766 |
-
[*Note 1*: The difference between `transform_exclusive_scan` and
|
| 5767 |
-
`transform_inclusive_scan` is that `transform_exclusive_scan` excludes
|
| 5768 |
-
the iᵗʰ input element from the iᵗʰ sum. If `binary_op` is not
|
| 5769 |
-
mathematically associative, the behavior of `transform_exclusive_scan`
|
| 5770 |
-
may be nondeterministic. `transform_exclusive_scan` does not apply
|
| 5771 |
-
`unary_op` to `init`. — *end note*]
|
| 5772 |
-
|
| 5773 |
-
### Transform inclusive scan <a id="transform.inclusive.scan">[[transform.inclusive.scan]]</a>
|
| 5774 |
-
|
| 5775 |
-
``` cpp
|
| 5776 |
-
template<class InputIterator, class OutputIterator,
|
| 5777 |
-
class BinaryOperation, class UnaryOperation>
|
| 5778 |
-
OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
|
| 5779 |
-
OutputIterator result,
|
| 5780 |
-
BinaryOperation binary_op,
|
| 5781 |
-
UnaryOperation unary_op);
|
| 5782 |
-
template<class ExecutionPolicy,
|
| 5783 |
-
class ForwardIterator1, class ForwardIterator2,
|
| 5784 |
-
class BinaryOperation, class UnaryOperation>
|
| 5785 |
-
ForwardIterator2 transform_inclusive_scan(ExecutionPolicy&& exec,
|
| 5786 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5787 |
-
ForwardIterator2 result,
|
| 5788 |
-
BinaryOperation binary_op,
|
| 5789 |
-
UnaryOperation unary_op);
|
| 5790 |
-
template<class InputIterator, class OutputIterator,
|
| 5791 |
-
class BinaryOperation, class UnaryOperation, class T>
|
| 5792 |
-
OutputIterator transform_inclusive_scan(InputIterator first, InputIterator last,
|
| 5793 |
-
OutputIterator result,
|
| 5794 |
-
BinaryOperation binary_op,
|
| 5795 |
-
UnaryOperation unary_op,
|
| 5796 |
-
T init);
|
| 5797 |
-
template<class ExecutionPolicy,
|
| 5798 |
-
class ForwardIterator1, class ForwardIterator2,
|
| 5799 |
-
class BinaryOperation, class UnaryOperation, class T>
|
| 5800 |
-
ForwardIterator2 transform_inclusive_scan(ExecutionPolicy&& exec,
|
| 5801 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5802 |
-
ForwardIterator2 result,
|
| 5803 |
-
BinaryOperation binary_op,
|
| 5804 |
-
UnaryOperation unary_op,
|
| 5805 |
-
T init);
|
| 5806 |
-
```
|
| 5807 |
-
|
| 5808 |
-
*Requires:*
|
| 5809 |
-
|
| 5810 |
-
- If `init` is provided, `T` shall be `MoveConstructible`
|
| 5811 |
-
(Table [[tab:moveconstructible]]); otherwise, `ForwardIterator1`’s
|
| 5812 |
-
value type shall be `MoveConstructible`.
|
| 5813 |
-
- If `init` is provided, all of
|
| 5814 |
-
- `binary_op(init, init)`,
|
| 5815 |
-
- `binary_op(init, unary_op(*first))`, and
|
| 5816 |
-
- `binary_op(unary_op(*first), unary_op(*first))`
|
| 5817 |
-
|
| 5818 |
-
shall be convertible to `T`; otherwise,
|
| 5819 |
-
`binary_op(unary_op(*first), unary_op(*first))` shall be convertible
|
| 5820 |
-
to `ForwardIterator1`’s value type.
|
| 5821 |
-
- Neither `unary_op` nor `binary_op` shall invalidate iterators or
|
| 5822 |
-
subranges, nor modify elements in the ranges \[`first`, `last`\] or
|
| 5823 |
-
\[`result`, `result + (last - first)`\].
|
| 5824 |
-
|
| 5825 |
-
*Effects:* For each integer `K` in \[`0`, `last - first`) assigns
|
| 5826 |
-
through `result + K` the value of
|
| 5827 |
-
|
| 5828 |
-
- *GENERALIZED_NONCOMMUTATIVE_SUM*(
|
| 5829 |
-
binary_op, init,
|
| 5830 |
-
unary_op(\*(first + 0)), unary_op(\*(first + 1)), ...,
|
| 5831 |
-
unary_op(\*(first + K)))
|
| 5832 |
-
if `init` is provided, or
|
| 5833 |
-
- *GENERALIZED_NONCOMMUTATIVE_SUM*(
|
| 5834 |
-
binary_op,
|
| 5835 |
-
unary_op(\*(first + 0)), unary_op(\*(first + 1)), ...,
|
| 5836 |
-
unary_op(\*(first + K)))
|
| 5837 |
-
otherwise.
|
| 5838 |
-
|
| 5839 |
-
*Returns:* The end of the resulting range beginning at `result`.
|
| 5840 |
-
|
| 5841 |
-
*Complexity:* 𝑂(`last - first`) applications each of `unary_op` and
|
| 5842 |
-
`binary_op`.
|
| 5843 |
-
|
| 5844 |
-
*Remarks:* `result` may be equal to `first`.
|
| 5845 |
-
|
| 5846 |
-
[*Note 1*: The difference between `transform_exclusive_scan` and
|
| 5847 |
-
`transform_inclusive_scan` is that `transform_inclusive_scan` includes
|
| 5848 |
-
the iᵗʰ input element in the iᵗʰ sum. If `binary_op` is not
|
| 5849 |
-
mathematically associative, the behavior of `transform_inclusive_scan`
|
| 5850 |
-
may be nondeterministic. `transform_inclusive_scan` does not apply
|
| 5851 |
-
`unary_op` to `init`. — *end note*]
|
| 5852 |
-
|
| 5853 |
-
### Adjacent difference <a id="adjacent.difference">[[adjacent.difference]]</a>
|
| 5854 |
-
|
| 5855 |
-
``` cpp
|
| 5856 |
-
template <class InputIterator, class OutputIterator>
|
| 5857 |
-
OutputIterator
|
| 5858 |
-
adjacent_difference(InputIterator first, InputIterator last,
|
| 5859 |
-
OutputIterator result);
|
| 5860 |
-
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2>
|
| 5861 |
-
ForwardIterator2
|
| 5862 |
-
adjacent_difference(ExecutionPolicy&& exec,
|
| 5863 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5864 |
-
ForwardIterator2 result);
|
| 5865 |
-
|
| 5866 |
-
template <class InputIterator, class OutputIterator, class BinaryOperation>
|
| 5867 |
-
OutputIterator
|
| 5868 |
-
adjacent_difference(InputIterator first, InputIterator last,
|
| 5869 |
-
OutputIterator result,
|
| 5870 |
-
BinaryOperation binary_op);
|
| 5871 |
-
template <class ExecutionPolicy, class ForwardIterator1, class ForwardIterator2,
|
| 5872 |
-
class BinaryOperation>
|
| 5873 |
-
ForwardIterator2
|
| 5874 |
-
adjacent_difference(ExecutionPolicy&& exec,
|
| 5875 |
-
ForwardIterator1 first, ForwardIterator1 last,
|
| 5876 |
-
ForwardIterator2 result,
|
| 5877 |
-
BinaryOperation binary_op);
|
| 5878 |
-
```
|
| 5879 |
-
|
| 5880 |
-
*Requires:*
|
| 5881 |
-
|
| 5882 |
-
- For the overloads with no `ExecutionPolicy`, `InputIterator`’s value
|
| 5883 |
-
type shall be `MoveAssignable` (Table [[tab:moveassignable]]) and
|
| 5884 |
-
shall be constructible from the type of `*first`. `acc` (defined
|
| 5885 |
-
below) shall be writable ([[iterator.requirements.general]]) to the
|
| 5886 |
-
`result` output iterator. The result of the expression `val - acc` or
|
| 5887 |
-
`binary_op(val, acc)` shall be writable to the `result` output
|
| 5888 |
-
iterator.
|
| 5889 |
-
- For the overloads with an `ExecutionPolicy`, the value type of
|
| 5890 |
-
`ForwardIterator1` shall be `CopyConstructible`
|
| 5891 |
-
(Table [[tab:copyconstructible]]), constructible from the expression
|
| 5892 |
-
`*first - *first` or `binary_op(*first, *first)`, and assignable to
|
| 5893 |
-
the value type of `ForwardIterator2`.
|
| 5894 |
-
- For all overloads, in the ranges \[`first`, `last`\] and \[`result`,
|
| 5895 |
-
`result + (last - first)`\], `binary_op` shall neither modify elements
|
| 5896 |
-
nor invalidate iterators or subranges.[^17]
|
| 5897 |
-
|
| 5898 |
-
*Effects:* For the overloads with no `ExecutionPolicy` and a non-empty
|
| 5899 |
-
range, the function creates an accumulator `acc` whose type is
|
| 5900 |
-
`InputIterator`’s value type, initializes it with `*first`, and assigns
|
| 5901 |
-
the result to `*result`. For every iterator `i` in \[`first + 1`,
|
| 5902 |
-
`last`) in order, creates an object `val` whose type is
|
| 5903 |
-
`InputIterator`’s value type, initializes it with `*i`, computes
|
| 5904 |
-
`val - acc` or `binary_op(val, acc)`, assigns the result to
|
| 5905 |
-
`*(result + (i - first))`, and move assigns from `val` to `acc`.
|
| 5906 |
-
|
| 5907 |
-
For the overloads with an `ExecutionPolicy` and a non-empty range, first
|
| 5908 |
-
the function creates an object whose type is `ForwardIterator1`’s value
|
| 5909 |
-
type, initializes it with `*first`, and assigns the result to `*result`.
|
| 5910 |
-
Then for every `d` in \[`1`, `last - first - 1`\], creates an object
|
| 5911 |
-
`val` whose type is `ForwardIterator1`’s value type, initializes it with
|
| 5912 |
-
`*(first + d) - *(first + d - 1)` or
|
| 5913 |
-
`binary_op(*(first + d), *(first + d - 1))`, and assigns the result to
|
| 5914 |
-
`*(result + d)`.
|
| 5915 |
-
|
| 5916 |
-
*Returns:* `result + (last - first)`.
|
| 5917 |
-
|
| 5918 |
-
*Complexity:* Exactly `(last - first) - 1` applications of the binary
|
| 5919 |
-
operation.
|
| 5920 |
-
|
| 5921 |
-
*Remarks:* For the overloads with no `ExecutionPolicy`, `result` may be
|
| 5922 |
-
equal to `first`. For the overloads with an `ExecutionPolicy`, the
|
| 5923 |
-
ranges \[`first`, `last`) and \[`result`, `result + (last - first)`)
|
| 5924 |
-
shall not overlap.
|
| 5925 |
-
|
| 5926 |
-
### Iota <a id="numeric.iota">[[numeric.iota]]</a>
|
| 5927 |
-
|
| 5928 |
-
``` cpp
|
| 5929 |
-
template <class ForwardIterator, class T>
|
| 5930 |
-
void iota(ForwardIterator first, ForwardIterator last, T value);
|
| 5931 |
-
```
|
| 5932 |
-
|
| 5933 |
-
*Requires:* `T` shall be convertible to `ForwardIterator`’s value type.
|
| 5934 |
-
The expression `++val`, where `val` has type `T`, shall be well formed.
|
| 5935 |
-
|
| 5936 |
-
*Effects:* For each element referred to by the iterator `i` in the range
|
| 5937 |
-
\[`first`, `last`), assigns `*i = value` and increments `value` as if by
|
| 5938 |
-
`++value`.
|
| 5939 |
-
|
| 5940 |
-
*Complexity:* Exactly `last - first` increments and assignments.
|
| 5941 |
-
|
| 5942 |
-
### Greatest common divisor <a id="numeric.ops.gcd">[[numeric.ops.gcd]]</a>
|
| 5943 |
-
|
| 5944 |
-
``` cpp
|
| 5945 |
-
template <class M, class N>
|
| 5946 |
-
constexpr common_type_t<M,N> gcd(M m, N n);
|
| 5947 |
-
```
|
| 5948 |
-
|
| 5949 |
-
*Requires:* `|m|` and `|n|` shall be representable as a value of
|
| 5950 |
-
`common_type_t<M, N>`.
|
| 5951 |
-
|
| 5952 |
-
[*Note 1*: These requirements ensure, for example, that
|
| 5953 |
-
`gcd(m, m) = |m|` is representable as a value of type
|
| 5954 |
-
`M`. — *end note*]
|
| 5955 |
-
|
| 5956 |
-
*Remarks:* If either `M` or `N` is not an integer type, or if either is
|
| 5957 |
-
cv `bool`, the program is ill-formed.
|
| 5958 |
-
|
| 5959 |
-
*Returns:* Zero when `m` and `n` are both zero. Otherwise, returns the
|
| 5960 |
-
greatest common divisor of `|m|` and `|n|`.
|
| 5961 |
-
|
| 5962 |
-
*Throws:* Nothing.
|
| 5963 |
-
|
| 5964 |
-
### Least common multiple <a id="numeric.ops.lcm">[[numeric.ops.lcm]]</a>
|
| 5965 |
-
|
| 5966 |
-
``` cpp
|
| 5967 |
-
template <class M, class N>
|
| 5968 |
-
constexpr common_type_t<M,N> lcm(M m, N n);
|
| 5969 |
-
```
|
| 5970 |
-
|
| 5971 |
-
*Requires:* `|m|` and `|n|` shall be representable as a value of
|
| 5972 |
-
`common_type_t<M, N>`. The least common multiple of `|m|` and `|n|`
|
| 5973 |
-
shall be representable as a value of type `common_type_t<M,N>`.
|
| 5974 |
-
|
| 5975 |
-
*Remarks:* If either `M` or `N` is not an integer type, or if either is
|
| 5976 |
-
cv `bool` the program is ill-formed.
|
| 5977 |
-
|
| 5978 |
-
*Returns:* Zero when either `m` or `n` is zero. Otherwise, returns the
|
| 5979 |
-
least common multiple of `|m|` and `|n|`.
|
| 5980 |
-
|
| 5981 |
-
*Throws:* Nothing.
|
| 5982 |
-
|
| 5983 |
## Mathematical functions for floating-point types <a id="c.math">[[c.math]]</a>
|
| 5984 |
|
| 5985 |
### Header `<cmath>` synopsis <a id="cmath.syn">[[cmath.syn]]</a>
|
| 5986 |
|
| 5987 |
``` cpp
|
|
@@ -6193,11 +5610,11 @@ namespace std {
|
|
| 6193 |
float fabsf(float x);
|
| 6194 |
long double fabsl(long double x);
|
| 6195 |
|
| 6196 |
float hypot(float x, float y); // see [library.c]
|
| 6197 |
double hypot(double x, double y);
|
| 6198 |
-
long double hypot(double x, double y); // see [library.c]
|
| 6199 |
float hypotf(float x, float y);
|
| 6200 |
long double hypotl(long double x, long double y);
|
| 6201 |
|
| 6202 |
// [c.math.hypot3], three-dimensional hypotenuse
|
| 6203 |
float hypot(float x, float y, float z);
|
|
@@ -6362,123 +5779,128 @@ namespace std {
|
|
| 6362 |
double fma(double x, double y, double z);
|
| 6363 |
long double fma(long double x, long double y, long double z); // see [library.c]
|
| 6364 |
float fmaf(float x, float y, float z);
|
| 6365 |
long double fmal(long double x, long double y, long double z);
|
| 6366 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 6367 |
// [c.math.fpclass], classification / comparison functions
|
| 6368 |
int fpclassify(float x);
|
| 6369 |
int fpclassify(double x);
|
| 6370 |
int fpclassify(long double x);
|
| 6371 |
|
| 6372 |
-
|
| 6373 |
-
|
| 6374 |
-
|
| 6375 |
|
| 6376 |
-
|
| 6377 |
-
|
| 6378 |
-
|
| 6379 |
|
| 6380 |
-
|
| 6381 |
-
|
| 6382 |
-
|
| 6383 |
|
| 6384 |
-
|
| 6385 |
-
|
| 6386 |
-
|
| 6387 |
|
| 6388 |
-
|
| 6389 |
-
|
| 6390 |
-
|
| 6391 |
|
| 6392 |
-
|
| 6393 |
-
|
| 6394 |
-
|
| 6395 |
|
| 6396 |
-
|
| 6397 |
-
|
| 6398 |
-
|
| 6399 |
|
| 6400 |
-
|
| 6401 |
-
|
| 6402 |
-
|
| 6403 |
|
| 6404 |
-
|
| 6405 |
-
|
| 6406 |
-
|
| 6407 |
|
| 6408 |
-
|
| 6409 |
-
|
| 6410 |
-
|
| 6411 |
|
| 6412 |
-
|
| 6413 |
-
|
| 6414 |
-
|
| 6415 |
|
| 6416 |
// [sf.cmath], mathematical special functions
|
| 6417 |
|
| 6418 |
-
// [sf.cmath.
|
| 6419 |
double assoc_laguerre(unsigned n, unsigned m, double x);
|
| 6420 |
float assoc_laguerref(unsigned n, unsigned m, float x);
|
| 6421 |
long double assoc_laguerrel(unsigned n, unsigned m, long double x);
|
| 6422 |
|
| 6423 |
-
// [sf.cmath.
|
| 6424 |
double assoc_legendre(unsigned l, unsigned m, double x);
|
| 6425 |
float assoc_legendref(unsigned l, unsigned m, float x);
|
| 6426 |
long double assoc_legendrel(unsigned l, unsigned m, long double x);
|
| 6427 |
|
| 6428 |
// [sf.cmath.beta], beta function
|
| 6429 |
double beta(double x, double y);
|
| 6430 |
float betaf(float x, float y);
|
| 6431 |
long double betal(long double x, long double y);
|
| 6432 |
|
| 6433 |
-
// [sf.cmath.
|
| 6434 |
double comp_ellint_1(double k);
|
| 6435 |
float comp_ellint_1f(float k);
|
| 6436 |
long double comp_ellint_1l(long double k);
|
| 6437 |
|
| 6438 |
-
// [sf.cmath.
|
| 6439 |
double comp_ellint_2(double k);
|
| 6440 |
float comp_ellint_2f(float k);
|
| 6441 |
long double comp_ellint_2l(long double k);
|
| 6442 |
|
| 6443 |
-
// [sf.cmath.
|
| 6444 |
double comp_ellint_3(double k, double nu);
|
| 6445 |
float comp_ellint_3f(float k, float nu);
|
| 6446 |
long double comp_ellint_3l(long double k, long double nu);
|
| 6447 |
|
| 6448 |
-
// [sf.cmath.
|
| 6449 |
double cyl_bessel_i(double nu, double x);
|
| 6450 |
float cyl_bessel_if(float nu, float x);
|
| 6451 |
long double cyl_bessel_il(long double nu, long double x);
|
| 6452 |
|
| 6453 |
-
// [sf.cmath.
|
| 6454 |
double cyl_bessel_j(double nu, double x);
|
| 6455 |
float cyl_bessel_jf(float nu, float x);
|
| 6456 |
long double cyl_bessel_jl(long double nu, long double x);
|
| 6457 |
|
| 6458 |
-
// [sf.cmath.
|
| 6459 |
double cyl_bessel_k(double nu, double x);
|
| 6460 |
float cyl_bessel_kf(float nu, float x);
|
| 6461 |
long double cyl_bessel_kl(long double nu, long double x);
|
| 6462 |
|
| 6463 |
-
// [sf.cmath.
|
| 6464 |
// cylindrical Bessel functions of the second kind
|
| 6465 |
double cyl_neumann(double nu, double x);
|
| 6466 |
float cyl_neumannf(float nu, float x);
|
| 6467 |
long double cyl_neumannl(long double nu, long double x);
|
| 6468 |
|
| 6469 |
-
// [sf.cmath.
|
| 6470 |
double ellint_1(double k, double phi);
|
| 6471 |
float ellint_1f(float k, float phi);
|
| 6472 |
long double ellint_1l(long double k, long double phi);
|
| 6473 |
|
| 6474 |
-
// [sf.cmath.
|
| 6475 |
double ellint_2(double k, double phi);
|
| 6476 |
float ellint_2f(float k, float phi);
|
| 6477 |
long double ellint_2l(long double k, long double phi);
|
| 6478 |
|
| 6479 |
-
// [sf.cmath.
|
| 6480 |
double ellint_3(double k, double nu, double phi);
|
| 6481 |
float ellint_3f(float k, float nu, float phi);
|
| 6482 |
long double ellint_3l(long double k, long double nu, long double phi);
|
| 6483 |
|
| 6484 |
// [sf.cmath.expint], exponential integral
|
|
@@ -6499,27 +5921,27 @@ namespace std {
|
|
| 6499 |
// [sf.cmath.legendre], Legendre polynomials
|
| 6500 |
double legendre(unsigned l, double x);
|
| 6501 |
float legendref(unsigned l, float x);
|
| 6502 |
long double legendrel(unsigned l, long double x);
|
| 6503 |
|
| 6504 |
-
// [sf.cmath.
|
| 6505 |
double riemann_zeta(double x);
|
| 6506 |
float riemann_zetaf(float x);
|
| 6507 |
long double riemann_zetal(long double x);
|
| 6508 |
|
| 6509 |
-
// [sf.cmath.
|
| 6510 |
double sph_bessel(unsigned n, double x);
|
| 6511 |
float sph_besself(unsigned n, float x);
|
| 6512 |
long double sph_bessell(unsigned n, long double x);
|
| 6513 |
|
| 6514 |
-
// [sf.cmath.
|
| 6515 |
double sph_legendre(unsigned l, unsigned m, double theta);
|
| 6516 |
float sph_legendref(unsigned l, unsigned m, float theta);
|
| 6517 |
long double sph_legendrel(unsigned l, unsigned m, long double theta);
|
| 6518 |
|
| 6519 |
-
// [sf.cmath.
|
| 6520 |
-
// spherical Bessel functions of the second kind
|
| 6521 |
double sph_neumann(unsigned n, double x);
|
| 6522 |
float sph_neumannf(unsigned n, float x);
|
| 6523 |
long double sph_neumannl(unsigned n, long double x);
|
| 6524 |
}
|
| 6525 |
```
|
|
@@ -6528,38 +5950,37 @@ The contents and meaning of the header `<cmath>` are the same as the C
|
|
| 6528 |
standard library header `<math.h>`, with the addition of a
|
| 6529 |
three-dimensional hypotenuse function ([[c.math.hypot3]]) and the
|
| 6530 |
mathematical special functions described in [[sf.cmath]].
|
| 6531 |
|
| 6532 |
[*Note 1*: Several functions have additional overloads in this
|
| 6533 |
-
|
| 6534 |
-
|
| 6535 |
|
| 6536 |
For each set of overloaded functions within `<cmath>`, with the
|
| 6537 |
exception of `abs`, there shall be additional overloads sufficient to
|
| 6538 |
ensure:
|
| 6539 |
|
| 6540 |
-
|
| 6541 |
parameter has type `long double`, then all arguments of arithmetic
|
| 6542 |
-
|
| 6543 |
-
|
| 6544 |
-
|
| 6545 |
`double` parameter has type `double` or an integer type, then all
|
| 6546 |
-
|
| 6547 |
-
|
| 6548 |
-
|
| 6549 |
-
|
| 6550 |
|
| 6551 |
-
[*Note
|
| 6552 |
compatible with C. — *end note*]
|
| 6553 |
|
| 6554 |
ISO C 7.12
|
| 6555 |
|
| 6556 |
### Absolute values <a id="c.math.abs">[[c.math.abs]]</a>
|
| 6557 |
|
| 6558 |
-
[*Note 1*: The headers `<cstdlib>`
|
| 6559 |
-
|
| 6560 |
-
subclause. — *end note*]
|
| 6561 |
|
| 6562 |
``` cpp
|
| 6563 |
int abs(int j);
|
| 6564 |
long int abs(long int j);
|
| 6565 |
long long int abs(long long int j);
|
|
@@ -6572,16 +5993,16 @@ long double abs(long double j);
|
|
| 6572 |
standard library for the functions `abs`, `labs`, `llabs`, `fabsf`,
|
| 6573 |
`fabs`, and `fabsl`.
|
| 6574 |
|
| 6575 |
*Remarks:* If `abs()` is called with an argument of type `X` for which
|
| 6576 |
`is_unsigned_v<X>` is `true` and if `X` cannot be converted to `int` by
|
| 6577 |
-
integral promotion
|
| 6578 |
|
| 6579 |
[*Note 1*: Arguments that can be promoted to `int` are permitted for
|
| 6580 |
compatibility with C. — *end note*]
|
| 6581 |
|
| 6582 |
-
ISO C 7.12.7.2, 7.22.6.1
|
| 6583 |
|
| 6584 |
### Three-dimensional hypotenuse <a id="c.math.hypot3">[[c.math.hypot3]]</a>
|
| 6585 |
|
| 6586 |
``` cpp
|
| 6587 |
float hypot(float x, float y, float z);
|
|
@@ -6589,10 +6010,34 @@ double hypot(double x, double y, double z);
|
|
| 6589 |
long double hypot(long double x, long double y, long double z);
|
| 6590 |
```
|
| 6591 |
|
| 6592 |
*Returns:* $\sqrt{x^2+y^2+z^2}$.
|
| 6593 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 6594 |
### Classification / comparison functions <a id="c.math.fpclass">[[c.math.fpclass]]</a>
|
| 6595 |
|
| 6596 |
The classification / comparison functions behave the same as the C
|
| 6597 |
macros with the corresponding names defined in the C standard library.
|
| 6598 |
Each function is overloaded for the three floating-point types.
|
|
@@ -6609,54 +6054,48 @@ a domain error for just those argument values for which:
|
|
| 6609 |
- the function description’s *Returns:* clause explicitly specifies a
|
| 6610 |
domain and those argument values fall outside the specified domain, or
|
| 6611 |
- the corresponding mathematical function value has a nonzero imaginary
|
| 6612 |
component, or
|
| 6613 |
- the corresponding mathematical function is not mathematically
|
| 6614 |
-
defined.[^
|
| 6615 |
|
| 6616 |
Unless otherwise specified, each function is defined for all finite
|
| 6617 |
values, for negative infinity, and for positive infinity.
|
| 6618 |
|
| 6619 |
-
#### Associated Laguerre polynomials <a id="sf.cmath.
|
| 6620 |
|
| 6621 |
``` cpp
|
| 6622 |
double assoc_laguerre(unsigned n, unsigned m, double x);
|
| 6623 |
float assoc_laguerref(unsigned n, unsigned m, float x);
|
| 6624 |
long double assoc_laguerrel(unsigned n, unsigned m, long double x);
|
| 6625 |
```
|
| 6626 |
|
| 6627 |
*Effects:* These functions compute the associated Laguerre polynomials
|
| 6628 |
of their respective arguments `n`, `m`, and `x`.
|
| 6629 |
|
| 6630 |
-
*Returns:* $$
|
| 6631 |
-
|
| 6632 |
-
|
| 6633 |
-
{\mathsf{d}x ^ m} \, \mathsf{L}_{n+m}(x),
|
| 6634 |
-
\quad \mbox{for $x \ge 0$}$$ where n is `n`, m is `m`, and x is
|
| 6635 |
`x`.
|
| 6636 |
|
| 6637 |
*Remarks:* The effect of calling each of these functions is
|
| 6638 |
*implementation-defined* if `n >= 128` or if `m >= 128`.
|
| 6639 |
|
| 6640 |
-
#### Associated Legendre functions <a id="sf.cmath.
|
| 6641 |
|
| 6642 |
``` cpp
|
| 6643 |
double assoc_legendre(unsigned l, unsigned m, double x);
|
| 6644 |
float assoc_legendref(unsigned l, unsigned m, float x);
|
| 6645 |
long double assoc_legendrel(unsigned l, unsigned m, long double x);
|
| 6646 |
```
|
| 6647 |
|
| 6648 |
*Effects:* These functions compute the associated Legendre functions of
|
| 6649 |
their respective arguments `l`, `m`, and `x`.
|
| 6650 |
|
| 6651 |
-
*Returns:* $$
|
| 6652 |
-
|
| 6653 |
-
|
| 6654 |
-
\:
|
| 6655 |
-
\frac{ \mathsf{d} ^ m}
|
| 6656 |
-
{ \mathsf{d}x ^ m} \, \mathsf{P}_\ell(x),
|
| 6657 |
-
\quad \mbox{for $|x| \le 1$}$$ where l is `l`, m is `m`, and x is
|
| 6658 |
`x`.
|
| 6659 |
|
| 6660 |
*Remarks:* The effect of calling each of these functions is
|
| 6661 |
*implementation-defined* if `l >= 128`.
|
| 6662 |
|
|
@@ -6669,115 +6108,105 @@ long double betal(long double x, long double y);
|
|
| 6669 |
```
|
| 6670 |
|
| 6671 |
*Effects:* These functions compute the beta function of their respective
|
| 6672 |
arguments `x` and `y`.
|
| 6673 |
|
| 6674 |
-
*Returns:*
|
| 6675 |
-
|
| 6676 |
-
|
| 6677 |
-
{ \Gamma(x+y) },
|
| 6678 |
-
\quad \mbox{for $x > 0$,\, $y > 0$}$$ where x is `x` and y is
|
| 6679 |
-
`y`.
|
| 6680 |
|
| 6681 |
-
#### Complete elliptic integral of the first kind <a id="sf.cmath.
|
| 6682 |
|
| 6683 |
``` cpp
|
| 6684 |
double comp_ellint_1(double k);
|
| 6685 |
float comp_ellint_1f(float k);
|
| 6686 |
long double comp_ellint_1l(long double k);
|
| 6687 |
```
|
| 6688 |
|
| 6689 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6690 |
first kind of their respective arguments `k`.
|
| 6691 |
|
| 6692 |
-
*Returns:*
|
| 6693 |
-
|
| 6694 |
-
|
| 6695 |
-
\quad \mbox{for $|k| \le 1$}$$ where k is `k`.
|
| 6696 |
|
| 6697 |
-
See also [[sf.cmath.
|
| 6698 |
|
| 6699 |
-
#### Complete elliptic integral of the second kind <a id="sf.cmath.
|
| 6700 |
|
| 6701 |
``` cpp
|
| 6702 |
double comp_ellint_2(double k);
|
| 6703 |
float comp_ellint_2f(float k);
|
| 6704 |
long double comp_ellint_2l(long double k);
|
| 6705 |
```
|
| 6706 |
|
| 6707 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6708 |
second kind of their respective arguments `k`.
|
| 6709 |
|
| 6710 |
-
*Returns:*
|
| 6711 |
-
|
| 6712 |
-
|
| 6713 |
-
\quad \mbox{for $|k| \le 1$}$$ where k is `k`.
|
| 6714 |
|
| 6715 |
-
See also [[sf.cmath.
|
| 6716 |
|
| 6717 |
-
#### Complete elliptic integral of the third kind <a id="sf.cmath.
|
| 6718 |
|
| 6719 |
``` cpp
|
| 6720 |
double comp_ellint_3(double k, double nu);
|
| 6721 |
float comp_ellint_3f(float k, float nu);
|
| 6722 |
long double comp_ellint_3l(long double k, long double nu);
|
| 6723 |
```
|
| 6724 |
|
| 6725 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6726 |
third kind of their respective arguments `k` and `nu`.
|
| 6727 |
|
| 6728 |
-
*Returns:*
|
| 6729 |
-
|
| 6730 |
-
|
| 6731 |
|
| 6732 |
-
See also [[sf.cmath.
|
| 6733 |
|
| 6734 |
-
#### Regular modified cylindrical Bessel functions <a id="sf.cmath.
|
| 6735 |
|
| 6736 |
``` cpp
|
| 6737 |
double cyl_bessel_i(double nu, double x);
|
| 6738 |
float cyl_bessel_if(float nu, float x);
|
| 6739 |
long double cyl_bessel_il(long double nu, long double x);
|
| 6740 |
```
|
| 6741 |
|
| 6742 |
*Effects:* These functions compute the regular modified cylindrical
|
| 6743 |
Bessel functions of their respective arguments `nu` and `x`.
|
| 6744 |
|
| 6745 |
-
*Returns:* $$
|
| 6746 |
-
|
| 6747 |
-
|
| 6748 |
-
|
| 6749 |
-
\sum_{k=0}^\infty \frac{(x/2)^{\nu+2k}}
|
| 6750 |
-
{k! \: \Gamma(\nu+k+1)},
|
| 6751 |
-
\quad \mbox{for $x \ge 0$}$$ where $\nu$ is `nu` and x is `x`.
|
| 6752 |
|
| 6753 |
*Remarks:* The effect of calling each of these functions is
|
| 6754 |
*implementation-defined* if `nu >= 128`.
|
| 6755 |
|
| 6756 |
-
See also [[sf.cmath.
|
| 6757 |
|
| 6758 |
-
#### Cylindrical Bessel functions of the first kind <a id="sf.cmath.
|
| 6759 |
|
| 6760 |
``` cpp
|
| 6761 |
double cyl_bessel_j(double nu, double x);
|
| 6762 |
float cyl_bessel_jf(float nu, float x);
|
| 6763 |
long double cyl_bessel_jl(long double nu, long double x);
|
| 6764 |
```
|
| 6765 |
|
| 6766 |
*Effects:* These functions compute the cylindrical Bessel functions of
|
| 6767 |
the first kind of their respective arguments `nu` and `x`.
|
| 6768 |
|
| 6769 |
-
*Returns:* $$
|
| 6770 |
-
|
| 6771 |
-
|
| 6772 |
-
{k! \: \Gamma(\nu+k+1)},
|
| 6773 |
-
\quad \mbox{for $x \ge 0$}$$ where $\nu$ is `nu` and x is `x`.
|
| 6774 |
|
| 6775 |
*Remarks:* The effect of calling each of these functions is
|
| 6776 |
*implementation-defined* if `nu >= 128`.
|
| 6777 |
|
| 6778 |
-
#### Irregular modified cylindrical Bessel functions <a id="sf.cmath.
|
| 6779 |
|
| 6780 |
``` cpp
|
| 6781 |
double cyl_bessel_k(double nu, double x);
|
| 6782 |
float cyl_bessel_kf(float nu, float x);
|
| 6783 |
long double cyl_bessel_kl(long double nu, long double x);
|
|
@@ -6810,14 +6239,14 @@ Bessel functions of their respective arguments `nu` and `x`.
|
|
| 6810 |
\right.$$ where $\nu$ is `nu` and x is `x`.
|
| 6811 |
|
| 6812 |
*Remarks:* The effect of calling each of these functions is
|
| 6813 |
*implementation-defined* if `nu >= 128`.
|
| 6814 |
|
| 6815 |
-
See also [[sf.cmath.
|
| 6816 |
-
[[sf.cmath.
|
| 6817 |
|
| 6818 |
-
#### Cylindrical Neumann functions <a id="sf.cmath.
|
| 6819 |
|
| 6820 |
``` cpp
|
| 6821 |
double cyl_neumann(double nu, double x);
|
| 6822 |
float cyl_neumannf(float nu, float x);
|
| 6823 |
long double cyl_neumannl(long double nu, long double x);
|
|
@@ -6845,13 +6274,13 @@ their respective arguments `nu` and `x`.
|
|
| 6845 |
\right.$$ where $\nu$ is `nu` and x is `x`.
|
| 6846 |
|
| 6847 |
*Remarks:* The effect of calling each of these functions is
|
| 6848 |
*implementation-defined* if `nu >= 128`.
|
| 6849 |
|
| 6850 |
-
See also [[sf.cmath.
|
| 6851 |
|
| 6852 |
-
#### Incomplete elliptic integral of the first kind <a id="sf.cmath.
|
| 6853 |
|
| 6854 |
``` cpp
|
| 6855 |
double ellint_1(double k, double phi);
|
| 6856 |
float ellint_1f(float k, float phi);
|
| 6857 |
long double ellint_1l(long double k, long double phi);
|
|
@@ -6859,17 +6288,15 @@ long double ellint_1l(long double k, long double phi);
|
|
| 6859 |
|
| 6860 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6861 |
the first kind of their respective arguments `k` and `phi` (`phi`
|
| 6862 |
measured in radians).
|
| 6863 |
|
| 6864 |
-
*Returns:* $$
|
| 6865 |
-
|
| 6866 |
-
|
| 6867 |
-
{\sqrt{1 - k^2 \sin^2 \theta}},
|
| 6868 |
-
\quad \mbox{for $|k| \le 1$}$$ where k is `k` and φ is `phi`.
|
| 6869 |
|
| 6870 |
-
#### Incomplete elliptic integral of the second kind <a id="sf.cmath.
|
| 6871 |
|
| 6872 |
``` cpp
|
| 6873 |
double ellint_2(double k, double phi);
|
| 6874 |
float ellint_2f(float k, float phi);
|
| 6875 |
long double ellint_2l(long double k, long double phi);
|
|
@@ -6877,16 +6304,15 @@ long double ellint_2l(long double k, long double phi);
|
|
| 6877 |
|
| 6878 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6879 |
the second kind of their respective arguments `k` and `phi` (`phi`
|
| 6880 |
measured in radians).
|
| 6881 |
|
| 6882 |
-
*Returns:*
|
| 6883 |
-
|
| 6884 |
-
|
| 6885 |
-
\quad \mbox{for $|k| \le 1$}$$ where k is `k` and φ is `phi`.
|
| 6886 |
|
| 6887 |
-
#### Incomplete elliptic integral of the third kind <a id="sf.cmath.
|
| 6888 |
|
| 6889 |
``` cpp
|
| 6890 |
double ellint_3(double k, double nu, double phi);
|
| 6891 |
float ellint_3f(float k, float nu, float phi);
|
| 6892 |
long double ellint_3l(long double k, long double nu, long double phi);
|
|
@@ -6894,16 +6320,13 @@ long double ellint_3l(long double k, long double nu, long double phi);
|
|
| 6894 |
|
| 6895 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6896 |
the third kind of their respective arguments `k`, `nu`, and `phi` (`phi`
|
| 6897 |
measured in radians).
|
| 6898 |
|
| 6899 |
-
*Returns:* $$
|
| 6900 |
-
|
| 6901 |
-
|
| 6902 |
-
{ (1 - \nu \, \sin^2 \theta) \sqrt{1 - k^2 \sin^2 \theta} },
|
| 6903 |
-
\quad \mbox{for $|k| \le 1$}$$ where $\nu$ is `nu`, k is `k`, and
|
| 6904 |
-
φ is `phi`.
|
| 6905 |
|
| 6906 |
#### Exponential integral <a id="sf.cmath.expint">[[sf.cmath.expint]]</a>
|
| 6907 |
|
| 6908 |
``` cpp
|
| 6909 |
double expint(double x);
|
|
@@ -6949,15 +6372,13 @@ long double laguerrel(unsigned n, long double x);
|
|
| 6949 |
```
|
| 6950 |
|
| 6951 |
*Effects:* These functions compute the Laguerre polynomials of their
|
| 6952 |
respective arguments `n` and `x`.
|
| 6953 |
|
| 6954 |
-
*Returns:* $$
|
| 6955 |
-
|
| 6956 |
-
|
| 6957 |
-
{ \mathsf{d}x ^ n} \, (x^n e^{-x}),
|
| 6958 |
-
\quad \mbox{for $x \ge 0$}$$ where n is `n` and x is `x`.
|
| 6959 |
|
| 6960 |
*Remarks:* The effect of calling each of these functions is
|
| 6961 |
*implementation-defined* if `n >= 128`.
|
| 6962 |
|
| 6963 |
#### Legendre polynomials <a id="sf.cmath.legendre">[[sf.cmath.legendre]]</a>
|
|
@@ -6969,22 +6390,19 @@ long double legendrel(unsigned l, long double x);
|
|
| 6969 |
```
|
| 6970 |
|
| 6971 |
*Effects:* These functions compute the Legendre polynomials of their
|
| 6972 |
respective arguments `l` and `x`.
|
| 6973 |
|
| 6974 |
-
*Returns:* $$
|
| 6975 |
-
|
| 6976 |
-
|
| 6977 |
-
|
| 6978 |
-
\frac{ \mathsf{d} ^ \ell}
|
| 6979 |
-
{ \mathsf{d}x ^ \ell} \, (x^2 - 1) ^ \ell,
|
| 6980 |
-
\quad \mbox{for $|x| \le 1$}$$ where l is `l` and x is `x`.
|
| 6981 |
|
| 6982 |
*Remarks:* The effect of calling each of these functions is
|
| 6983 |
*implementation-defined* if `l >= 128`.
|
| 6984 |
|
| 6985 |
-
#### Riemann zeta function <a id="sf.cmath.
|
| 6986 |
|
| 6987 |
``` cpp
|
| 6988 |
double riemann_zeta(double x);
|
| 6989 |
float riemann_zetaf(float x);
|
| 6990 |
long double riemann_zetal(long double x);
|
|
@@ -7014,32 +6432,31 @@ respective arguments `x`.
|
|
| 7014 |
& \mbox{for $x < 0$}
|
| 7015 |
\end{array}
|
| 7016 |
\right.
|
| 7017 |
\;$$ where x is `x`.
|
| 7018 |
|
| 7019 |
-
#### Spherical Bessel functions of the first kind <a id="sf.cmath.
|
| 7020 |
|
| 7021 |
``` cpp
|
| 7022 |
double sph_bessel(unsigned n, double x);
|
| 7023 |
float sph_besself(unsigned n, float x);
|
| 7024 |
long double sph_bessell(unsigned n, long double x);
|
| 7025 |
```
|
| 7026 |
|
| 7027 |
*Effects:* These functions compute the spherical Bessel functions of the
|
| 7028 |
first kind of their respective arguments `n` and `x`.
|
| 7029 |
|
| 7030 |
-
*Returns:*
|
| 7031 |
-
|
| 7032 |
-
|
| 7033 |
-
\quad \mbox{for $x \ge 0$}$$ where n is `n` and x is `x`.
|
| 7034 |
|
| 7035 |
*Remarks:* The effect of calling each of these functions is
|
| 7036 |
*implementation-defined* if `n >= 128`.
|
| 7037 |
|
| 7038 |
-
See also [[sf.cmath.
|
| 7039 |
|
| 7040 |
-
#### Spherical associated Legendre functions <a id="sf.cmath.
|
| 7041 |
|
| 7042 |
``` cpp
|
| 7043 |
double sph_legendre(unsigned l, unsigned m, double theta);
|
| 7044 |
float sph_legendref(unsigned l, unsigned m, float theta);
|
| 7045 |
long double sph_legendrel(unsigned l, unsigned m, long double theta);
|
|
@@ -7047,30 +6464,23 @@ long double sph_legendrel(unsigned l, unsigned m, long double theta);
|
|
| 7047 |
|
| 7048 |
*Effects:* These functions compute the spherical associated Legendre
|
| 7049 |
functions of their respective arguments `l`, `m`, and `theta` (`theta`
|
| 7050 |
measured in radians).
|
| 7051 |
|
| 7052 |
-
*Returns:* $$
|
| 7053 |
-
|
| 7054 |
-
\
|
| 7055 |
-
|
| 7056 |
-
|
| 7057 |
-
{4 \pi}
|
| 7058 |
-
\frac{(\ell - m)!}
|
| 7059 |
-
{(\ell + m)!}
|
| 7060 |
-
\right]^{1/2}
|
| 7061 |
-
\mathsf{P}_\ell^m
|
| 7062 |
-
( \cos\theta ) e ^ {i m \phi},
|
| 7063 |
-
\quad \mbox{for $|m| \le \ell$}$$ and l is `l`, m is `m`, and θ
|
| 7064 |
is `theta`.
|
| 7065 |
|
| 7066 |
*Remarks:* The effect of calling each of these functions is
|
| 7067 |
*implementation-defined* if `l >= 128`.
|
| 7068 |
|
| 7069 |
-
See also [[sf.cmath.
|
| 7070 |
|
| 7071 |
-
#### Spherical Neumann functions <a id="sf.cmath.
|
| 7072 |
|
| 7073 |
``` cpp
|
| 7074 |
double sph_neumann(unsigned n, double x);
|
| 7075 |
float sph_neumannf(unsigned n, float x);
|
| 7076 |
long double sph_neumannl(unsigned n, long double x);
|
|
@@ -7078,32 +6488,103 @@ long double sph_neumannl(unsigned n, long double x);
|
|
| 7078 |
|
| 7079 |
*Effects:* These functions compute the spherical Neumann functions, also
|
| 7080 |
known as the spherical Bessel functions of the second kind, of their
|
| 7081 |
respective arguments `n` and `x`.
|
| 7082 |
|
| 7083 |
-
*Returns:*
|
| 7084 |
-
|
| 7085 |
-
|
| 7086 |
-
\quad \mbox{for $x \ge 0$}$$ where n is `n` and x is `x`.
|
| 7087 |
|
| 7088 |
*Remarks:* The effect of calling each of these functions is
|
| 7089 |
*implementation-defined* if `n >= 128`.
|
| 7090 |
|
| 7091 |
-
See also [[sf.cmath.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 7092 |
|
| 7093 |
<!-- Link reference definitions -->
|
| 7094 |
-
[
|
| 7095 |
-
[adjacent.difference]: #adjacent.difference
|
| 7096 |
-
[algorithms]: algorithms.md#algorithms
|
| 7097 |
-
[bad.alloc]: language.md#bad.alloc
|
| 7098 |
[basic.fundamental]: basic.md#basic.fundamental
|
| 7099 |
[basic.stc.thread]: basic.md#basic.stc.thread
|
| 7100 |
[basic.types]: basic.md#basic.types
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 7101 |
[c.math]: #c.math
|
| 7102 |
[c.math.abs]: #c.math.abs
|
| 7103 |
[c.math.fpclass]: #c.math.fpclass
|
| 7104 |
[c.math.hypot3]: #c.math.hypot3
|
|
|
|
| 7105 |
[c.math.rand]: #c.math.rand
|
| 7106 |
[cfenv]: #cfenv
|
| 7107 |
[cfenv.syn]: #cfenv.syn
|
| 7108 |
[class.gslice]: #class.gslice
|
| 7109 |
[class.gslice.overview]: #class.gslice.overview
|
|
@@ -7120,49 +6601,47 @@ See also [[sf.cmath.cyl_neumann]].
|
|
| 7120 |
[complex.special]: #complex.special
|
| 7121 |
[complex.syn]: #complex.syn
|
| 7122 |
[complex.transcendentals]: #complex.transcendentals
|
| 7123 |
[complex.value.ops]: #complex.value.ops
|
| 7124 |
[cons.slice]: #cons.slice
|
| 7125 |
-
[conv.prom]:
|
| 7126 |
[cpp.pragma]: cpp.md#cpp.pragma
|
| 7127 |
-
[
|
| 7128 |
-
[
|
|
|
|
| 7129 |
[dcl.init]: dcl.md#dcl.init
|
| 7130 |
-
[
|
| 7131 |
-
[function.objects]: utilities.md#function.objects
|
| 7132 |
[gslice.access]: #gslice.access
|
| 7133 |
[gslice.array.assign]: #gslice.array.assign
|
| 7134 |
[gslice.array.comp.assign]: #gslice.array.comp.assign
|
| 7135 |
[gslice.array.fill]: #gslice.array.fill
|
| 7136 |
[gslice.cons]: #gslice.cons
|
| 7137 |
[implimits]: limits.md#implimits
|
| 7138 |
-
[inclusive.scan]: #inclusive.scan
|
| 7139 |
[indirect.array.assign]: #indirect.array.assign
|
| 7140 |
[indirect.array.comp.assign]: #indirect.array.comp.assign
|
| 7141 |
[indirect.array.fill]: #indirect.array.fill
|
| 7142 |
-
[inner.product]: #inner.product
|
| 7143 |
[input.iterators]: iterators.md#input.iterators
|
| 7144 |
[input.output]: input.md#input.output
|
|
|
|
| 7145 |
[iostate.flags]: input.md#iostate.flags
|
| 7146 |
[istream.formatted]: input.md#istream.formatted
|
|
|
|
| 7147 |
[iterator.requirements.general]: iterators.md#iterator.requirements.general
|
| 7148 |
[library.c]: library.md#library.c
|
| 7149 |
[mask.array.assign]: #mask.array.assign
|
| 7150 |
[mask.array.comp.assign]: #mask.array.comp.assign
|
| 7151 |
[mask.array.fill]: #mask.array.fill
|
|
|
|
|
|
|
| 7152 |
[numarray]: #numarray
|
| 7153 |
-
[
|
| 7154 |
-
[
|
| 7155 |
-
[numeric.ops.gcd]: #numeric.ops.gcd
|
| 7156 |
-
[numeric.ops.lcm]: #numeric.ops.lcm
|
| 7157 |
-
[numeric.ops.overview]: #numeric.ops.overview
|
| 7158 |
[numeric.requirements]: #numeric.requirements
|
| 7159 |
[numerics]: #numerics
|
| 7160 |
-
[numerics.defns]: #numerics.defns
|
| 7161 |
[numerics.general]: #numerics.general
|
|
|
|
| 7162 |
[output.iterators]: iterators.md#output.iterators
|
| 7163 |
-
[partial.sum]: #partial.sum
|
| 7164 |
[rand]: #rand
|
| 7165 |
[rand.adapt]: #rand.adapt
|
| 7166 |
[rand.adapt.disc]: #rand.adapt.disc
|
| 7167 |
[rand.adapt.general]: #rand.adapt.general
|
| 7168 |
[rand.adapt.ibits]: #rand.adapt.ibits
|
|
@@ -7210,64 +6689,52 @@ See also [[sf.cmath.cyl_neumann]].
|
|
| 7210 |
[rand.synopsis]: #rand.synopsis
|
| 7211 |
[rand.util]: #rand.util
|
| 7212 |
[rand.util.canonical]: #rand.util.canonical
|
| 7213 |
[rand.util.seedseq]: #rand.util.seedseq
|
| 7214 |
[random.access.iterators]: iterators.md#random.access.iterators
|
| 7215 |
-
[reduce]: #reduce
|
| 7216 |
[res.on.data.races]: library.md#res.on.data.races
|
| 7217 |
[sf.cmath]: #sf.cmath
|
| 7218 |
-
[sf.cmath.
|
| 7219 |
-
[sf.cmath.
|
| 7220 |
[sf.cmath.beta]: #sf.cmath.beta
|
| 7221 |
-
[sf.cmath.
|
| 7222 |
-
[sf.cmath.
|
| 7223 |
-
[sf.cmath.
|
| 7224 |
-
[sf.cmath.
|
| 7225 |
-
[sf.cmath.
|
| 7226 |
-
[sf.cmath.
|
| 7227 |
-
[sf.cmath.
|
| 7228 |
-
[sf.cmath.
|
| 7229 |
-
[sf.cmath.
|
| 7230 |
-
[sf.cmath.
|
| 7231 |
[sf.cmath.expint]: #sf.cmath.expint
|
| 7232 |
[sf.cmath.hermite]: #sf.cmath.hermite
|
| 7233 |
[sf.cmath.laguerre]: #sf.cmath.laguerre
|
| 7234 |
[sf.cmath.legendre]: #sf.cmath.legendre
|
| 7235 |
-
[sf.cmath.
|
| 7236 |
-
[sf.cmath.
|
| 7237 |
-
[sf.cmath.
|
| 7238 |
-
[sf.cmath.
|
| 7239 |
[slice.access]: #slice.access
|
| 7240 |
[slice.arr.assign]: #slice.arr.assign
|
| 7241 |
[slice.arr.comp.assign]: #slice.arr.comp.assign
|
| 7242 |
[slice.arr.fill]: #slice.arr.fill
|
|
|
|
| 7243 |
[strings]: strings.md#strings
|
| 7244 |
-
[tab:RandomDistribution]: #tab:RandomDistribution
|
| 7245 |
-
[tab:RandomEngine]: #tab:RandomEngine
|
| 7246 |
-
[tab:SeedSequence]: #tab:SeedSequence
|
| 7247 |
-
[tab:UniformRandomBitGenerator]: #tab:UniformRandomBitGenerator
|
| 7248 |
-
[tab:copyassignable]: #tab:copyassignable
|
| 7249 |
-
[tab:copyconstructible]: #tab:copyconstructible
|
| 7250 |
-
[tab:equalitycomparable]: #tab:equalitycomparable
|
| 7251 |
-
[tab:iterator.input.requirements]: iterators.md#tab:iterator.input.requirements
|
| 7252 |
-
[tab:moveassignable]: #tab:moveassignable
|
| 7253 |
-
[tab:moveconstructible]: #tab:moveconstructible
|
| 7254 |
-
[tab:numerics.lib.summary]: #tab:numerics.lib.summary
|
| 7255 |
[template.gslice.array]: #template.gslice.array
|
| 7256 |
[template.gslice.array.overview]: #template.gslice.array.overview
|
| 7257 |
[template.indirect.array]: #template.indirect.array
|
| 7258 |
[template.indirect.array.overview]: #template.indirect.array.overview
|
| 7259 |
[template.mask.array]: #template.mask.array
|
| 7260 |
[template.mask.array.overview]: #template.mask.array.overview
|
| 7261 |
[template.slice.array]: #template.slice.array
|
| 7262 |
[template.slice.array.overview]: #template.slice.array.overview
|
| 7263 |
[template.valarray]: #template.valarray
|
| 7264 |
[template.valarray.overview]: #template.valarray.overview
|
|
|
|
| 7265 |
[thread.thread.class]: thread.md#thread.thread.class
|
| 7266 |
-
[
|
| 7267 |
-
[transform.inclusive.scan]: #transform.inclusive.scan
|
| 7268 |
-
[transform.reduce]: #transform.reduce
|
| 7269 |
[valarray.access]: #valarray.access
|
| 7270 |
[valarray.assign]: #valarray.assign
|
| 7271 |
[valarray.binary]: #valarray.binary
|
| 7272 |
[valarray.cassign]: #valarray.cassign
|
| 7273 |
[valarray.comparison]: #valarray.comparison
|
|
@@ -7278,11 +6745,10 @@ See also [[sf.cmath.cyl_neumann]].
|
|
| 7278 |
[valarray.special]: #valarray.special
|
| 7279 |
[valarray.sub]: #valarray.sub
|
| 7280 |
[valarray.syn]: #valarray.syn
|
| 7281 |
[valarray.transcend]: #valarray.transcend
|
| 7282 |
[valarray.unary]: #valarray.unary
|
| 7283 |
-
[vector]: containers.md#vector
|
| 7284 |
|
| 7285 |
[^1]: In other words, value types. These include arithmetic types,
|
| 7286 |
pointers, the library class `complex`, and instantiations of
|
| 7287 |
`valarray` for value types.
|
| 7288 |
|
|
@@ -7303,17 +6769,17 @@ See also [[sf.cmath.cyl_neumann]].
|
|
| 7303 |
[^6]: The distribution corresponding to this probability density
|
| 7304 |
function is also known (with a possible change of variable) as the
|
| 7305 |
Gumbel Type I, the log-Weibull, or the Fisher-Tippett Type I
|
| 7306 |
distribution.
|
| 7307 |
|
| 7308 |
-
[^7]:
|
| 7309 |
-
|
| 7310 |
-
|
| 7311 |
|
| 7312 |
[^8]: The intent is to specify an array template that has the minimum
|
| 7313 |
functionality necessary to address aliasing ambiguities and the
|
| 7314 |
-
proliferation of
|
| 7315 |
neither a matrix class nor a field class. However, it is a very
|
| 7316 |
useful building block for designing such classes.
|
| 7317 |
|
| 7318 |
[^9]: This default constructor is essential, since arrays of `valarray`
|
| 7319 |
may be useful. After initialization, the length of an empty array
|
|
@@ -7322,32 +6788,19 @@ See also [[sf.cmath.cyl_neumann]].
|
|
| 7322 |
[^10]: This constructor is the preferred method for converting a C array
|
| 7323 |
to a `valarray` object.
|
| 7324 |
|
| 7325 |
[^11]: This copy constructor creates a distinct array rather than an
|
| 7326 |
alias. Implementations in which arrays share storage are permitted,
|
| 7327 |
-
but they
|
| 7328 |
-
that arrays are conceptually distinct.
|
| 7329 |
|
| 7330 |
[^12]: BLAS stands for *Basic Linear Algebra Subprograms.* C++ programs
|
| 7331 |
may instantiate this class. See, for example, Dongarra, Du Croz,
|
| 7332 |
Duff, and Hammerling: *A set of Level 3 Basic Linear Algebra
|
| 7333 |
Subprograms*; Technical Report MCS-P1-0888, Argonne National
|
| 7334 |
Laboratory (USA), Mathematics and Computer Science Division, August,
|
| 7335 |
1988.
|
| 7336 |
|
| 7337 |
-
[^13]:
|
| 7338 |
-
|
| 7339 |
-
[^14]: `accumulate` is similar to the APL reduction operator and Common
|
| 7340 |
-
Lisp reduce function, but it avoids the difficulty of defining the
|
| 7341 |
-
result of reduction on an empty sequence by always requiring an
|
| 7342 |
-
initial value.
|
| 7343 |
-
|
| 7344 |
-
[^15]: The use of fully closed ranges is intentional.
|
| 7345 |
-
|
| 7346 |
-
[^16]: The use of fully closed ranges is intentional.
|
| 7347 |
-
|
| 7348 |
-
[^17]: The use of fully closed ranges is intentional.
|
| 7349 |
-
|
| 7350 |
-
[^18]: A mathematical function is mathematically defined for a given set
|
| 7351 |
of argument values (a) if it is explicitly defined for that set of
|
| 7352 |
argument values, or (b) if its limiting value exists and does not
|
| 7353 |
depend on the direction of approach.
|
|
|
|
| 5 |
This Clause describes components that C++ programs may use to perform
|
| 6 |
seminumerical operations.
|
| 7 |
|
| 8 |
The following subclauses describe components for complex number types,
|
| 9 |
random number generation, numeric ( *n*-at-a-time) arrays, generalized
|
| 10 |
+
numeric algorithms, and mathematical constants and functions for
|
| 11 |
+
floating-point types, as summarized in [[numerics.summary]].
|
| 12 |
|
| 13 |
+
**Table: Numerics library summary** <a id="numerics.summary">[numerics.summary]</a>
|
| 14 |
|
| 15 |
| Subclause | | Header |
|
| 16 |
+
| ------------------------ | ----------------------------------------------- | ---------------------- |
|
|
|
|
| 17 |
| [[numeric.requirements]] | Requirements | |
|
| 18 |
| [[cfenv]] | Floating-point environment | `<cfenv>` |
|
| 19 |
| [[complex.numbers]] | Complex numbers | `<complex>` |
|
| 20 |
+
| [[bit]] | Bit manipulation | `<bit>` |
|
| 21 |
| [[rand]] | Random number generation | `<random>` |
|
| 22 |
| [[numarray]] | Numeric arrays | `<valarray>` |
|
| 23 |
+
| [[c.math]] | Mathematical functions for floating-point types | `<cmath>`, `<cstdlib>` |
|
| 24 |
+
| [[numbers]] | Numbers | `<numbers>` |
|
|
|
|
| 25 |
|
| 26 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 27 |
## Numeric type requirements <a id="numeric.requirements">[[numeric.requirements]]</a>
|
| 28 |
|
| 29 |
The `complex` and `valarray` components are parameterized by the type of
|
| 30 |
information they contain and manipulate. A C++ program shall instantiate
|
| 31 |
+
these components only with a numeric type. A *numeric type* is a
|
| 32 |
+
cv-unqualified object type `T` that meets the
|
| 33 |
+
*Cpp17DefaultConstructible*, *Cpp17CopyConstructible*,
|
| 34 |
+
*Cpp17CopyAssignable*, and *Cpp17Destructible* requirements
|
| 35 |
+
[[utility.arg.requirements]]. [^1]
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 36 |
|
| 37 |
If any operation on `T` throws an exception the effects are undefined.
|
| 38 |
|
| 39 |
In addition, many member and related functions of `valarray<T>` can be
|
| 40 |
successfully instantiated and will exhibit well-defined behavior if and
|
| 41 |
+
only if `T` meets additional requirements specified for each such member
|
| 42 |
+
or related function.
|
| 43 |
|
| 44 |
+
[*Example 1*: It is valid to instantiate `valarray<complex>`, but
|
| 45 |
`operator>()` will not be successfully instantiated for
|
| 46 |
`valarray<complex>` operands, since `complex` does not have any ordering
|
| 47 |
operators. — *end example*]
|
| 48 |
|
| 49 |
## The floating-point environment <a id="cfenv">[[cfenv]]</a>
|
| 50 |
|
| 51 |
### Header `<cfenv>` synopsis <a id="cfenv.syn">[[cfenv.syn]]</a>
|
| 52 |
|
| 53 |
``` cpp
|
| 54 |
#define FE_ALL_EXCEPT see below
|
| 55 |
+
#define FE_DIVBYZERO see below // optional
|
| 56 |
+
#define FE_INEXACT see below // optional
|
| 57 |
+
#define FE_INVALID see below // optional
|
| 58 |
+
#define FE_OVERFLOW see below // optional
|
| 59 |
+
#define FE_UNDERFLOW see below // optional
|
| 60 |
|
| 61 |
+
#define FE_DOWNWARD see below // optional
|
| 62 |
+
#define FE_TONEAREST see below // optional
|
| 63 |
+
#define FE_TOWARDZERO see below // optional
|
| 64 |
+
#define FE_UPWARD see below // optional
|
| 65 |
|
| 66 |
#define FE_DFL_ENV see below
|
| 67 |
|
| 68 |
namespace std {
|
| 69 |
// types
|
|
|
|
| 88 |
```
|
| 89 |
|
| 90 |
The contents and meaning of the header `<cfenv>` are the same as the C
|
| 91 |
standard library header `<fenv.h>`.
|
| 92 |
|
| 93 |
+
[*Note 1*: This document does not require an implementation to support
|
| 94 |
+
the `FENV_ACCESS` pragma; it is *implementation-defined* [[cpp.pragma]]
|
| 95 |
+
whether the pragma is supported. As a consequence, it is
|
| 96 |
+
*implementation-defined* whether these functions can be used to test
|
| 97 |
+
floating-point status flags, set floating-point control modes, or run
|
| 98 |
+
under non-default mode settings. If the pragma is used to enable control
|
| 99 |
+
over the floating-point environment, this document does not specify the
|
| 100 |
+
effect on floating-point evaluation in constant
|
| 101 |
+
expressions. — *end note*]
|
| 102 |
|
| 103 |
+
The floating-point environment has thread storage duration
|
| 104 |
+
[[basic.stc.thread]]. The initial state for a thread’s floating-point
|
| 105 |
environment is the state of the floating-point environment of the thread
|
| 106 |
+
that constructs the corresponding `thread` object
|
| 107 |
+
[[thread.thread.class]] or `jthread` object [[thread.jthread.class]] at
|
| 108 |
+
the time it constructed the object.
|
| 109 |
|
| 110 |
[*Note 2*: That is, the child thread gets the floating-point state of
|
| 111 |
the parent thread at the time of the child’s creation. — *end note*]
|
| 112 |
|
| 113 |
+
A separate floating-point environment is maintained for each thread.
|
| 114 |
+
Each function accesses the environment corresponding to its calling
|
| 115 |
+
thread.
|
| 116 |
|
| 117 |
+
See also: ISO C 7.6
|
| 118 |
|
| 119 |
## Complex numbers <a id="complex.numbers">[[complex.numbers]]</a>
|
| 120 |
|
| 121 |
The header `<complex>` defines a class template, and numerous functions
|
| 122 |
for representing and manipulating complex numbers.
|
| 123 |
|
| 124 |
The effect of instantiating the template `complex` for any type other
|
| 125 |
than `float`, `double`, or `long double` is unspecified. The
|
| 126 |
specializations `complex<float>`, `complex<double>`, and
|
| 127 |
+
`complex<long double>` are literal types [[basic.types]].
|
| 128 |
|
| 129 |
If the result of a function is not mathematically defined or not in the
|
| 130 |
range of representable values for its type, the behavior is undefined.
|
| 131 |
|
| 132 |
+
If `z` is an lvalue of type cv `complex<T>` then:
|
| 133 |
|
| 134 |
+
- the expression `reinterpret_cast<cv T(&)[2]>(z)` is well-formed,
|
| 135 |
+
- `reinterpret_cast<cv T(&)[2]>(z)[0]` designates the real part of `z`,
|
| 136 |
+
and
|
| 137 |
+
- `reinterpret_cast<cv T(&)[2]>(z)[1]` designates the imaginary part of
|
| 138 |
+
`z`.
|
| 139 |
|
| 140 |
Moreover, if `a` is an expression of type cv `complex<T>*` and the
|
| 141 |
expression `a[i]` is well-defined for an integer expression `i`, then:
|
| 142 |
|
| 143 |
+
- `reinterpret_cast<cv T*>(a)[2*i]` designates the real part of `a[i]`,
|
| 144 |
+
and
|
| 145 |
+
- `reinterpret_cast<cv T*>(a)[2*i + 1]` designates the imaginary part of
|
| 146 |
+
`a[i]`.
|
| 147 |
|
| 148 |
### Header `<complex>` synopsis <a id="complex.syn">[[complex.syn]]</a>
|
| 149 |
|
| 150 |
``` cpp
|
| 151 |
namespace std {
|
| 152 |
+
// [complex], class template complex
|
| 153 |
template<class T> class complex;
|
| 154 |
+
|
| 155 |
+
// [complex.special], specializations
|
| 156 |
template<> class complex<float>;
|
| 157 |
template<> class complex<double>;
|
| 158 |
template<> class complex<long double>;
|
| 159 |
|
| 160 |
// [complex.ops], operators
|
| 161 |
+
template<class T> constexpr complex<T> operator+(const complex<T>&, const complex<T>&);
|
| 162 |
+
template<class T> constexpr complex<T> operator+(const complex<T>&, const T&);
|
| 163 |
+
template<class T> constexpr complex<T> operator+(const T&, const complex<T>&);
|
|
|
|
| 164 |
|
| 165 |
+
template<class T> constexpr complex<T> operator-(const complex<T>&, const complex<T>&);
|
| 166 |
+
template<class T> constexpr complex<T> operator-(const complex<T>&, const T&);
|
| 167 |
+
template<class T> constexpr complex<T> operator-(const T&, const complex<T>&);
|
|
|
|
| 168 |
|
| 169 |
+
template<class T> constexpr complex<T> operator*(const complex<T>&, const complex<T>&);
|
| 170 |
+
template<class T> constexpr complex<T> operator*(const complex<T>&, const T&);
|
| 171 |
+
template<class T> constexpr complex<T> operator*(const T&, const complex<T>&);
|
|
|
|
| 172 |
|
| 173 |
+
template<class T> constexpr complex<T> operator/(const complex<T>&, const complex<T>&);
|
| 174 |
+
template<class T> constexpr complex<T> operator/(const complex<T>&, const T&);
|
| 175 |
+
template<class T> constexpr complex<T> operator/(const T&, const complex<T>&);
|
|
|
|
| 176 |
|
| 177 |
+
template<class T> constexpr complex<T> operator+(const complex<T>&);
|
| 178 |
+
template<class T> constexpr complex<T> operator-(const complex<T>&);
|
| 179 |
|
| 180 |
+
template<class T> constexpr bool operator==(const complex<T>&, const complex<T>&);
|
|
|
|
| 181 |
template<class T> constexpr bool operator==(const complex<T>&, const T&);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 182 |
|
| 183 |
template<class T, class charT, class traits>
|
| 184 |
+
basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>&, complex<T>&);
|
|
|
|
| 185 |
|
| 186 |
template<class T, class charT, class traits>
|
| 187 |
+
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>&, const complex<T>&);
|
|
|
|
| 188 |
|
| 189 |
// [complex.value.ops], values
|
| 190 |
template<class T> constexpr T real(const complex<T>&);
|
| 191 |
template<class T> constexpr T imag(const complex<T>&);
|
| 192 |
|
| 193 |
template<class T> T abs(const complex<T>&);
|
| 194 |
template<class T> T arg(const complex<T>&);
|
| 195 |
+
template<class T> constexpr T norm(const complex<T>&);
|
| 196 |
|
| 197 |
+
template<class T> constexpr complex<T> conj(const complex<T>&);
|
| 198 |
template<class T> complex<T> proj(const complex<T>&);
|
| 199 |
+
template<class T> complex<T> polar(const T&, const T& = T());
|
| 200 |
|
| 201 |
// [complex.transcendentals], transcendentals
|
| 202 |
template<class T> complex<T> acos(const complex<T>&);
|
| 203 |
template<class T> complex<T> asin(const complex<T>&);
|
| 204 |
template<class T> complex<T> atan(const complex<T>&);
|
|
|
|
| 239 |
|
| 240 |
### Class template `complex` <a id="complex">[[complex]]</a>
|
| 241 |
|
| 242 |
``` cpp
|
| 243 |
namespace std {
|
| 244 |
+
template<class T> class complex {
|
|
|
|
| 245 |
public:
|
| 246 |
using value_type = T;
|
| 247 |
|
| 248 |
constexpr complex(const T& re = T(), const T& im = T());
|
| 249 |
constexpr complex(const complex&);
|
| 250 |
template<class X> constexpr complex(const complex<X>&);
|
| 251 |
|
| 252 |
constexpr T real() const;
|
| 253 |
+
constexpr void real(T);
|
| 254 |
constexpr T imag() const;
|
| 255 |
+
constexpr void imag(T);
|
| 256 |
|
| 257 |
+
constexpr complex& operator= (const T&);
|
| 258 |
+
constexpr complex& operator+=(const T&);
|
| 259 |
+
constexpr complex& operator-=(const T&);
|
| 260 |
+
constexpr complex& operator*=(const T&);
|
| 261 |
+
constexpr complex& operator/=(const T&);
|
| 262 |
|
| 263 |
+
constexpr complex& operator=(const complex&);
|
| 264 |
+
template<class X> constexpr complex& operator= (const complex<X>&);
|
| 265 |
+
template<class X> constexpr complex& operator+=(const complex<X>&);
|
| 266 |
+
template<class X> constexpr complex& operator-=(const complex<X>&);
|
| 267 |
+
template<class X> constexpr complex& operator*=(const complex<X>&);
|
| 268 |
+
template<class X> constexpr complex& operator/=(const complex<X>&);
|
| 269 |
};
|
| 270 |
}
|
| 271 |
```
|
| 272 |
|
| 273 |
The class `complex` describes an object that can store the Cartesian
|
| 274 |
components, `real()` and `imag()`, of a complex number.
|
| 275 |
|
| 276 |
+
### Specializations <a id="complex.special">[[complex.special]]</a>
|
| 277 |
|
| 278 |
``` cpp
|
| 279 |
namespace std {
|
| 280 |
template<> class complex<float> {
|
| 281 |
public:
|
| 282 |
using value_type = float;
|
| 283 |
|
| 284 |
constexpr complex(float re = 0.0f, float im = 0.0f);
|
| 285 |
+
constexpr complex(const complex<float>&) = default;
|
| 286 |
constexpr explicit complex(const complex<double>&);
|
| 287 |
constexpr explicit complex(const complex<long double>&);
|
| 288 |
|
| 289 |
constexpr float real() const;
|
| 290 |
+
constexpr void real(float);
|
| 291 |
constexpr float imag() const;
|
| 292 |
+
constexpr void imag(float);
|
| 293 |
|
| 294 |
+
constexpr complex& operator= (float);
|
| 295 |
+
constexpr complex& operator+=(float);
|
| 296 |
+
constexpr complex& operator-=(float);
|
| 297 |
+
constexpr complex& operator*=(float);
|
| 298 |
+
constexpr complex& operator/=(float);
|
| 299 |
|
| 300 |
+
constexpr complex& operator=(const complex&);
|
| 301 |
+
template<class X> constexpr complex& operator= (const complex<X>&);
|
| 302 |
+
template<class X> constexpr complex& operator+=(const complex<X>&);
|
| 303 |
+
template<class X> constexpr complex& operator-=(const complex<X>&);
|
| 304 |
+
template<class X> constexpr complex& operator*=(const complex<X>&);
|
| 305 |
+
template<class X> constexpr complex& operator/=(const complex<X>&);
|
| 306 |
};
|
| 307 |
|
| 308 |
template<> class complex<double> {
|
| 309 |
public:
|
| 310 |
using value_type = double;
|
| 311 |
|
| 312 |
constexpr complex(double re = 0.0, double im = 0.0);
|
| 313 |
constexpr complex(const complex<float>&);
|
| 314 |
+
constexpr complex(const complex<double>&) = default;
|
| 315 |
constexpr explicit complex(const complex<long double>&);
|
| 316 |
|
| 317 |
constexpr double real() const;
|
| 318 |
+
constexpr void real(double);
|
| 319 |
constexpr double imag() const;
|
| 320 |
+
constexpr void imag(double);
|
| 321 |
|
| 322 |
+
constexpr complex& operator= (double);
|
| 323 |
+
constexpr complex& operator+=(double);
|
| 324 |
+
constexpr complex& operator-=(double);
|
| 325 |
+
constexpr complex& operator*=(double);
|
| 326 |
+
constexpr complex& operator/=(double);
|
| 327 |
|
| 328 |
+
constexpr complex& operator=(const complex&);
|
| 329 |
+
template<class X> constexpr complex& operator= (const complex<X>&);
|
| 330 |
+
template<class X> constexpr complex& operator+=(const complex<X>&);
|
| 331 |
+
template<class X> constexpr complex& operator-=(const complex<X>&);
|
| 332 |
+
template<class X> constexpr complex& operator*=(const complex<X>&);
|
| 333 |
+
template<class X> constexpr complex& operator/=(const complex<X>&);
|
| 334 |
};
|
| 335 |
|
| 336 |
template<> class complex<long double> {
|
| 337 |
public:
|
| 338 |
using value_type = long double;
|
| 339 |
|
| 340 |
constexpr complex(long double re = 0.0L, long double im = 0.0L);
|
| 341 |
constexpr complex(const complex<float>&);
|
| 342 |
constexpr complex(const complex<double>&);
|
| 343 |
+
constexpr complex(const complex<long double>&) = default;
|
| 344 |
|
| 345 |
constexpr long double real() const;
|
| 346 |
+
constexpr void real(long double);
|
| 347 |
constexpr long double imag() const;
|
| 348 |
+
constexpr void imag(long double);
|
| 349 |
|
| 350 |
+
constexpr complex& operator= (long double);
|
| 351 |
+
constexpr complex& operator+=(long double);
|
| 352 |
+
constexpr complex& operator-=(long double);
|
| 353 |
+
constexpr complex& operator*=(long double);
|
| 354 |
+
constexpr complex& operator/=(long double);
|
|
|
|
| 355 |
|
| 356 |
+
constexpr complex& operator=(const complex&);
|
| 357 |
+
template<class X> constexpr complex& operator= (const complex<X>&);
|
| 358 |
+
template<class X> constexpr complex& operator+=(const complex<X>&);
|
| 359 |
+
template<class X> constexpr complex& operator-=(const complex<X>&);
|
| 360 |
+
template<class X> constexpr complex& operator*=(const complex<X>&);
|
| 361 |
+
template<class X> constexpr complex& operator/=(const complex<X>&);
|
| 362 |
};
|
| 363 |
}
|
| 364 |
```
|
| 365 |
|
| 366 |
+
### Member functions <a id="complex.members">[[complex.members]]</a>
|
| 367 |
|
| 368 |
``` cpp
|
| 369 |
template<class T> constexpr complex(const T& re = T(), const T& im = T());
|
| 370 |
```
|
| 371 |
|
| 372 |
+
*Ensures:* `real() == re && imag() == im` is `true`.
|
|
|
|
|
|
|
| 373 |
|
| 374 |
``` cpp
|
| 375 |
constexpr T real() const;
|
| 376 |
```
|
| 377 |
|
| 378 |
*Returns:* The value of the real component.
|
| 379 |
|
| 380 |
``` cpp
|
| 381 |
+
constexpr void real(T val);
|
| 382 |
```
|
| 383 |
|
| 384 |
*Effects:* Assigns `val` to the real component.
|
| 385 |
|
| 386 |
``` cpp
|
|
|
|
| 388 |
```
|
| 389 |
|
| 390 |
*Returns:* The value of the imaginary component.
|
| 391 |
|
| 392 |
``` cpp
|
| 393 |
+
constexpr void imag(T val);
|
| 394 |
```
|
| 395 |
|
| 396 |
*Effects:* Assigns `val` to the imaginary component.
|
| 397 |
|
| 398 |
+
### Member operators <a id="complex.member.ops">[[complex.member.ops]]</a>
|
| 399 |
|
| 400 |
``` cpp
|
| 401 |
+
constexpr complex& operator+=(const T& rhs);
|
| 402 |
```
|
| 403 |
|
| 404 |
*Effects:* Adds the scalar value `rhs` to the real part of the complex
|
| 405 |
value `*this` and stores the result in the real part of `*this`, leaving
|
| 406 |
the imaginary part unchanged.
|
| 407 |
|
| 408 |
*Returns:* `*this`.
|
| 409 |
|
| 410 |
``` cpp
|
| 411 |
+
constexpr complex& operator-=(const T& rhs);
|
| 412 |
```
|
| 413 |
|
| 414 |
*Effects:* Subtracts the scalar value `rhs` from the real part of the
|
| 415 |
complex value `*this` and stores the result in the real part of `*this`,
|
| 416 |
leaving the imaginary part unchanged.
|
| 417 |
|
| 418 |
*Returns:* `*this`.
|
| 419 |
|
| 420 |
``` cpp
|
| 421 |
+
constexpr complex& operator*=(const T& rhs);
|
| 422 |
```
|
| 423 |
|
| 424 |
*Effects:* Multiplies the scalar value `rhs` by the complex value
|
| 425 |
`*this` and stores the result in `*this`.
|
| 426 |
|
| 427 |
*Returns:* `*this`.
|
| 428 |
|
| 429 |
``` cpp
|
| 430 |
+
constexpr complex& operator/=(const T& rhs);
|
| 431 |
```
|
| 432 |
|
| 433 |
*Effects:* Divides the scalar value `rhs` into the complex value `*this`
|
| 434 |
and stores the result in `*this`.
|
| 435 |
|
| 436 |
*Returns:* `*this`.
|
| 437 |
|
| 438 |
``` cpp
|
| 439 |
+
template<class X> constexpr complex& operator+=(const complex<X>& rhs);
|
| 440 |
```
|
| 441 |
|
| 442 |
*Effects:* Adds the complex value `rhs` to the complex value `*this` and
|
| 443 |
stores the sum in `*this`.
|
| 444 |
|
| 445 |
*Returns:* `*this`.
|
| 446 |
|
| 447 |
``` cpp
|
| 448 |
+
template<class X> constexpr complex& operator-=(const complex<X>& rhs);
|
| 449 |
```
|
| 450 |
|
| 451 |
*Effects:* Subtracts the complex value `rhs` from the complex value
|
| 452 |
`*this` and stores the difference in `*this`.
|
| 453 |
|
| 454 |
*Returns:* `*this`.
|
| 455 |
|
| 456 |
``` cpp
|
| 457 |
+
template<class X> constexpr complex& operator*=(const complex<X>& rhs);
|
| 458 |
```
|
| 459 |
|
| 460 |
*Effects:* Multiplies the complex value `rhs` by the complex value
|
| 461 |
`*this` and stores the product in `*this`.
|
| 462 |
|
| 463 |
*Returns:* `*this`.
|
| 464 |
|
| 465 |
``` cpp
|
| 466 |
+
template<class X> constexpr complex& operator/=(const complex<X>& rhs);
|
| 467 |
```
|
| 468 |
|
| 469 |
*Effects:* Divides the complex value `rhs` into the complex value
|
| 470 |
`*this` and stores the quotient in `*this`.
|
| 471 |
|
| 472 |
*Returns:* `*this`.
|
| 473 |
|
| 474 |
+
### Non-member operations <a id="complex.ops">[[complex.ops]]</a>
|
| 475 |
|
| 476 |
``` cpp
|
| 477 |
+
template<class T> constexpr complex<T> operator+(const complex<T>& lhs);
|
| 478 |
```
|
| 479 |
|
| 480 |
*Returns:* `complex<T>(lhs)`.
|
| 481 |
|
|
|
|
|
|
|
| 482 |
``` cpp
|
| 483 |
+
template<class T> constexpr complex<T> operator+(const complex<T>& lhs, const complex<T>& rhs);
|
| 484 |
+
template<class T> constexpr complex<T> operator+(const complex<T>& lhs, const T& rhs);
|
| 485 |
+
template<class T> constexpr complex<T> operator+(const T& lhs, const complex<T>& rhs);
|
| 486 |
```
|
| 487 |
|
| 488 |
*Returns:* `complex<T>(lhs) += rhs`.
|
| 489 |
|
| 490 |
``` cpp
|
| 491 |
+
template<class T> constexpr complex<T> operator-(const complex<T>& lhs);
|
| 492 |
```
|
| 493 |
|
| 494 |
*Returns:* `complex<T>(-lhs.real(),-lhs.imag())`.
|
| 495 |
|
|
|
|
|
|
|
| 496 |
``` cpp
|
| 497 |
+
template<class T> constexpr complex<T> operator-(const complex<T>& lhs, const complex<T>& rhs);
|
| 498 |
+
template<class T> constexpr complex<T> operator-(const complex<T>& lhs, const T& rhs);
|
| 499 |
+
template<class T> constexpr complex<T> operator-(const T& lhs, const complex<T>& rhs);
|
| 500 |
```
|
| 501 |
|
| 502 |
*Returns:* `complex<T>(lhs) -= rhs`.
|
| 503 |
|
| 504 |
``` cpp
|
| 505 |
+
template<class T> constexpr complex<T> operator*(const complex<T>& lhs, const complex<T>& rhs);
|
| 506 |
+
template<class T> constexpr complex<T> operator*(const complex<T>& lhs, const T& rhs);
|
| 507 |
+
template<class T> constexpr complex<T> operator*(const T& lhs, const complex<T>& rhs);
|
| 508 |
```
|
| 509 |
|
| 510 |
*Returns:* `complex<T>(lhs) *= rhs`.
|
| 511 |
|
| 512 |
``` cpp
|
| 513 |
+
template<class T> constexpr complex<T> operator/(const complex<T>& lhs, const complex<T>& rhs);
|
| 514 |
+
template<class T> constexpr complex<T> operator/(const complex<T>& lhs, const T& rhs);
|
| 515 |
+
template<class T> constexpr complex<T> operator/(const T& lhs, const complex<T>& rhs);
|
| 516 |
```
|
| 517 |
|
| 518 |
*Returns:* `complex<T>(lhs) /= rhs`.
|
| 519 |
|
| 520 |
``` cpp
|
| 521 |
template<class T> constexpr bool operator==(const complex<T>& lhs, const complex<T>& rhs);
|
| 522 |
template<class T> constexpr bool operator==(const complex<T>& lhs, const T& rhs);
|
|
|
|
| 523 |
```
|
| 524 |
|
| 525 |
*Returns:* `lhs.real() == rhs.real() && lhs.imag() == rhs.imag()`.
|
| 526 |
|
| 527 |
*Remarks:* The imaginary part is assumed to be `T()`, or 0.0, for the
|
| 528 |
`T` arguments.
|
| 529 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 530 |
``` cpp
|
| 531 |
template<class T, class charT, class traits>
|
| 532 |
+
basic_istream<charT, traits>& operator>>(basic_istream<charT, traits>& is, complex<T>& x);
|
|
|
|
| 533 |
```
|
| 534 |
|
| 535 |
+
*Preconditions:* The input values are convertible to `T`.
|
| 536 |
|
| 537 |
*Effects:* Extracts a complex number `x` of the form: `u`, `(u)`, or
|
| 538 |
`(u,v)`, where `u` is the real part and `v` is the imaginary
|
| 539 |
+
part [[istream.formatted]].
|
| 540 |
|
| 541 |
If bad input is encountered, calls `is.setstate(ios_base::failbit)`
|
| 542 |
+
(which may throw `ios_base::failure` [[iostate.flags]]).
|
| 543 |
|
| 544 |
*Returns:* `is`.
|
| 545 |
|
| 546 |
*Remarks:* This extraction is performed as a series of simpler
|
| 547 |
extractions. Therefore, the skipping of whitespace is specified to be
|
| 548 |
the same for each of the simpler extractions.
|
| 549 |
|
| 550 |
``` cpp
|
| 551 |
template<class T, class charT, class traits>
|
| 552 |
+
basic_ostream<charT, traits>& operator<<(basic_ostream<charT, traits>& o, const complex<T>& x);
|
|
|
|
| 553 |
```
|
| 554 |
|
| 555 |
*Effects:* Inserts the complex number `x` onto the stream `o` as if it
|
| 556 |
were implemented as follows:
|
| 557 |
|
|
|
|
| 568 |
character, the use of comma as a field separator can be ambiguous.
|
| 569 |
Inserting `showpoint` into the output stream forces all outputs to show
|
| 570 |
an explicit decimal point character; as a result, all inserted sequences
|
| 571 |
of complex numbers can be extracted unambiguously. — *end note*]
|
| 572 |
|
| 573 |
+
### Value operations <a id="complex.value.ops">[[complex.value.ops]]</a>
|
| 574 |
|
| 575 |
``` cpp
|
| 576 |
template<class T> constexpr T real(const complex<T>& x);
|
| 577 |
```
|
| 578 |
|
|
|
|
| 595 |
```
|
| 596 |
|
| 597 |
*Returns:* The phase angle of `x`, or `atan2(imag(x), real(x))`.
|
| 598 |
|
| 599 |
``` cpp
|
| 600 |
+
template<class T> constexpr T norm(const complex<T>& x);
|
| 601 |
```
|
| 602 |
|
| 603 |
*Returns:* The squared magnitude of `x`.
|
| 604 |
|
| 605 |
``` cpp
|
| 606 |
+
template<class T> constexpr complex<T> conj(const complex<T>& x);
|
| 607 |
```
|
| 608 |
|
| 609 |
*Returns:* The complex conjugate of `x`.
|
| 610 |
|
| 611 |
``` cpp
|
| 612 |
template<class T> complex<T> proj(const complex<T>& x);
|
| 613 |
```
|
| 614 |
|
| 615 |
*Returns:* The projection of `x` onto the Riemann sphere.
|
| 616 |
|
| 617 |
+
*Remarks:* Behaves the same as the C function `cproj`. See also: ISO C
|
| 618 |
+
7.3.9.5
|
| 619 |
|
| 620 |
``` cpp
|
| 621 |
+
template<class T> complex<T> polar(const T& rho, const T& theta = T());
|
| 622 |
```
|
| 623 |
|
| 624 |
+
*Preconditions:* `rho` is non-negative and non-NaN. `theta` is finite.
|
|
|
|
| 625 |
|
| 626 |
*Returns:* The `complex` value corresponding to a complex number whose
|
| 627 |
magnitude is `rho` and whose phase angle is `theta`.
|
| 628 |
|
| 629 |
+
### Transcendentals <a id="complex.transcendentals">[[complex.transcendentals]]</a>
|
| 630 |
|
| 631 |
``` cpp
|
| 632 |
template<class T> complex<T> acos(const complex<T>& x);
|
| 633 |
```
|
| 634 |
|
| 635 |
*Returns:* The complex arc cosine of `x`.
|
| 636 |
|
| 637 |
+
*Remarks:* Behaves the same as the C function `cacos`. See also: ISO C
|
| 638 |
+
7.3.5.1
|
| 639 |
|
| 640 |
``` cpp
|
| 641 |
template<class T> complex<T> asin(const complex<T>& x);
|
| 642 |
```
|
| 643 |
|
| 644 |
*Returns:* The complex arc sine of `x`.
|
| 645 |
|
| 646 |
+
*Remarks:* Behaves the same as the C function `casin`. See also: ISO C
|
| 647 |
+
7.3.5.2
|
| 648 |
|
| 649 |
``` cpp
|
| 650 |
template<class T> complex<T> atan(const complex<T>& x);
|
| 651 |
```
|
| 652 |
|
| 653 |
*Returns:* The complex arc tangent of `x`.
|
| 654 |
|
| 655 |
+
*Remarks:* Behaves the same as the C function `catan`. See also: ISO C
|
| 656 |
+
7.3.5.3
|
| 657 |
|
| 658 |
``` cpp
|
| 659 |
template<class T> complex<T> acosh(const complex<T>& x);
|
| 660 |
```
|
| 661 |
|
| 662 |
*Returns:* The complex arc hyperbolic cosine of `x`.
|
| 663 |
|
| 664 |
+
*Remarks:* Behaves the same as the C function `cacosh`. See also: ISO C
|
| 665 |
+
7.3.6.1
|
| 666 |
|
| 667 |
``` cpp
|
| 668 |
template<class T> complex<T> asinh(const complex<T>& x);
|
| 669 |
```
|
| 670 |
|
| 671 |
*Returns:* The complex arc hyperbolic sine of `x`.
|
| 672 |
|
| 673 |
+
*Remarks:* Behaves the same as the C function `casinh`. See also: ISO C
|
| 674 |
+
7.3.6.2
|
| 675 |
|
| 676 |
``` cpp
|
| 677 |
template<class T> complex<T> atanh(const complex<T>& x);
|
| 678 |
```
|
| 679 |
|
| 680 |
*Returns:* The complex arc hyperbolic tangent of `x`.
|
| 681 |
|
| 682 |
+
*Remarks:* Behaves the same as the C function `catanh`. See also: ISO C
|
| 683 |
+
7.3.6.3
|
| 684 |
|
| 685 |
``` cpp
|
| 686 |
template<class T> complex<T> cos(const complex<T>& x);
|
| 687 |
```
|
| 688 |
|
|
|
|
| 703 |
``` cpp
|
| 704 |
template<class T> complex<T> log(const complex<T>& x);
|
| 705 |
```
|
| 706 |
|
| 707 |
*Returns:* The complex natural (base-e) logarithm of `x`. For all `x`,
|
| 708 |
+
`imag(log(x))` lies in the interval \[-π, π\].
|
| 709 |
+
|
| 710 |
+
[*Note 1*: The semantics of this function are intended to be the same
|
| 711 |
+
in C++ as they are for `clog` in C. — *end note*]
|
| 712 |
|
| 713 |
*Remarks:* The branch cuts are along the negative real axis.
|
| 714 |
|
| 715 |
``` cpp
|
| 716 |
template<class T> complex<T> log10(const complex<T>& x);
|
|
|
|
| 748 |
``` cpp
|
| 749 |
template<class T> complex<T> sqrt(const complex<T>& x);
|
| 750 |
```
|
| 751 |
|
| 752 |
*Returns:* The complex square root of `x`, in the range of the right
|
| 753 |
+
half-plane.
|
| 754 |
+
|
| 755 |
+
[*Note 2*: The semantics of this function are intended to be the same
|
| 756 |
+
in C++ as they are for `csqrt` in C. — *end note*]
|
| 757 |
|
| 758 |
*Remarks:* The branch cuts are along the negative real axis.
|
| 759 |
|
| 760 |
``` cpp
|
| 761 |
template<class T> complex<T> tan(const complex<T>& x);
|
|
|
|
| 777 |
arg norm
|
| 778 |
conj proj
|
| 779 |
imag real
|
| 780 |
```
|
| 781 |
|
| 782 |
+
where `norm`, `conj`, `imag`, and `real` are `constexpr` overloads.
|
| 783 |
+
|
| 784 |
The additional overloads shall be sufficient to ensure:
|
| 785 |
|
| 786 |
+
- If the argument has type `long double`, then it is effectively cast to
|
| 787 |
+
`complex<long double>`.
|
| 788 |
+
- Otherwise, if the argument has type `double` or an integer type, then
|
| 789 |
+
it is effectively cast to `complex<{}double>`.
|
| 790 |
+
- Otherwise, if the argument has type `float`, then it is effectively
|
| 791 |
cast to `complex<float>`.
|
| 792 |
|
| 793 |
Function template `pow` shall have additional overloads sufficient to
|
| 794 |
ensure, for a call with at least one argument of type `complex<T>`:
|
| 795 |
|
| 796 |
+
- If either argument has type `complex<long double>` or type `long
|
| 797 |
double`, then both arguments are effectively cast to
|
| 798 |
`complex<long double>`.
|
| 799 |
+
- Otherwise, if either argument has type `complex<double>`, `double`, or
|
| 800 |
+
an integer type, then both arguments are effectively cast to
|
| 801 |
`complex<double>`.
|
| 802 |
+
- Otherwise, if either argument has type `complex<float>` or `float`,
|
| 803 |
then both arguments are effectively cast to `complex<float>`.
|
| 804 |
|
| 805 |
### Suffixes for complex number literals <a id="complex.literals">[[complex.literals]]</a>
|
| 806 |
|
| 807 |
+
This subclause describes literal suffixes for constructing complex
|
| 808 |
+
number literals. The suffixes `i`, `il`, and `if` create complex numbers
|
| 809 |
+
of the types `complex<double>`, `complex<long double>`, and
|
| 810 |
+
`complex<float>` respectively, with their imaginary part denoted by the
|
| 811 |
+
given literal number and the real part being zero.
|
| 812 |
|
| 813 |
``` cpp
|
| 814 |
constexpr complex<long double> operator""il(long double d);
|
| 815 |
constexpr complex<long double> operator""il(unsigned long long d);
|
| 816 |
```
|
|
|
|
| 829 |
constexpr complex<float> operator""if(unsigned long long d);
|
| 830 |
```
|
| 831 |
|
| 832 |
*Returns:* `complex<float>{0.0f, static_cast<float>(d)}`.
|
| 833 |
|
| 834 |
+
## Bit manipulation <a id="bit">[[bit]]</a>
|
| 835 |
+
|
| 836 |
+
### General <a id="bit.general">[[bit.general]]</a>
|
| 837 |
+
|
| 838 |
+
The header `<bit>` provides components to access, manipulate and process
|
| 839 |
+
both individual bits and bit sequences.
|
| 840 |
+
|
| 841 |
+
### Header `<bit>` synopsis <a id="bit.syn">[[bit.syn]]</a>
|
| 842 |
+
|
| 843 |
+
``` cpp
|
| 844 |
+
namespace std {
|
| 845 |
+
// [bit.cast], bit_cast
|
| 846 |
+
template<class To, class From>
|
| 847 |
+
constexpr To bit_cast(const From& from) noexcept;
|
| 848 |
+
|
| 849 |
+
// [bit.pow.two], integral powers of 2
|
| 850 |
+
template<class T>
|
| 851 |
+
constexpr bool has_single_bit(T x) noexcept;
|
| 852 |
+
template<class T>
|
| 853 |
+
constexpr T bit_ceil(T x);
|
| 854 |
+
template<class T>
|
| 855 |
+
constexpr T bit_floor(T x) noexcept;
|
| 856 |
+
template<class T>
|
| 857 |
+
constexpr T bit_width(T x) noexcept;
|
| 858 |
+
|
| 859 |
+
// [bit.rotate], rotating
|
| 860 |
+
template<class T>
|
| 861 |
+
[[nodiscard]] constexpr T rotl(T x, int s) noexcept;
|
| 862 |
+
template<class T>
|
| 863 |
+
[[nodiscard]] constexpr T rotr(T x, int s) noexcept;
|
| 864 |
+
|
| 865 |
+
// [bit.count], counting
|
| 866 |
+
template<class T>
|
| 867 |
+
constexpr int countl_zero(T x) noexcept;
|
| 868 |
+
template<class T>
|
| 869 |
+
constexpr int countl_one(T x) noexcept;
|
| 870 |
+
template<class T>
|
| 871 |
+
constexpr int countr_zero(T x) noexcept;
|
| 872 |
+
template<class T>
|
| 873 |
+
constexpr int countr_one(T x) noexcept;
|
| 874 |
+
template<class T>
|
| 875 |
+
constexpr int popcount(T x) noexcept;
|
| 876 |
+
|
| 877 |
+
// [bit.endian], endian
|
| 878 |
+
enum class endian {
|
| 879 |
+
little = see below,
|
| 880 |
+
big = see below,
|
| 881 |
+
native = see below
|
| 882 |
+
};
|
| 883 |
+
}
|
| 884 |
+
```
|
| 885 |
+
|
| 886 |
+
### Function template `bit_cast` <a id="bit.cast">[[bit.cast]]</a>
|
| 887 |
+
|
| 888 |
+
``` cpp
|
| 889 |
+
template<class To, class From>
|
| 890 |
+
constexpr To bit_cast(const From& from) noexcept;
|
| 891 |
+
```
|
| 892 |
+
|
| 893 |
+
*Constraints:*
|
| 894 |
+
|
| 895 |
+
- `sizeof(To) == sizeof(From)` is `true`;
|
| 896 |
+
- `is_trivially_copyable_v<To>` is `true`; and
|
| 897 |
+
- `is_trivially_copyable_v<From>` is `true`.
|
| 898 |
+
|
| 899 |
+
*Returns:* An object of type `To`. Implicitly creates objects nested
|
| 900 |
+
within the result [[intro.object]]. Each bit of the value representation
|
| 901 |
+
of the result is equal to the corresponding bit in the object
|
| 902 |
+
representation of `from`. Padding bits of the result are unspecified.
|
| 903 |
+
For the result and each object created within it, if there is no value
|
| 904 |
+
of the object’s type corresponding to the value representation produced,
|
| 905 |
+
the behavior is undefined. If there are multiple such values, which
|
| 906 |
+
value is produced is unspecified.
|
| 907 |
+
|
| 908 |
+
*Remarks:* This function is `constexpr` if and only if `To`, `From`, and
|
| 909 |
+
the types of all subobjects of `To` and `From` are types `T` such that:
|
| 910 |
+
|
| 911 |
+
- `is_union_v<T>` is `false`;
|
| 912 |
+
- `is_pointer_v<T>` is `false`;
|
| 913 |
+
- `is_member_pointer_v<T>` is `false`;
|
| 914 |
+
- `is_volatile_v<T>` is `false`; and
|
| 915 |
+
- `T` has no non-static data members of reference type.
|
| 916 |
+
|
| 917 |
+
### Integral powers of 2 <a id="bit.pow.two">[[bit.pow.two]]</a>
|
| 918 |
+
|
| 919 |
+
``` cpp
|
| 920 |
+
template<class T>
|
| 921 |
+
constexpr bool has_single_bit(T x) noexcept;
|
| 922 |
+
```
|
| 923 |
+
|
| 924 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 925 |
+
|
| 926 |
+
*Returns:* `true` if `x` is an integral power of two; `false` otherwise.
|
| 927 |
+
|
| 928 |
+
``` cpp
|
| 929 |
+
template<class T>
|
| 930 |
+
constexpr T bit_ceil(T x);
|
| 931 |
+
```
|
| 932 |
+
|
| 933 |
+
Let N be the smallest power of 2 greater than or equal to `x`.
|
| 934 |
+
|
| 935 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 936 |
+
|
| 937 |
+
*Preconditions:* N is representable as a value of type `T`.
|
| 938 |
+
|
| 939 |
+
*Returns:* N.
|
| 940 |
+
|
| 941 |
+
*Throws:* Nothing.
|
| 942 |
+
|
| 943 |
+
*Remarks:* A function call expression that violates the precondition in
|
| 944 |
+
the *Preconditions:* element is not a core constant
|
| 945 |
+
expression [[expr.const]].
|
| 946 |
+
|
| 947 |
+
``` cpp
|
| 948 |
+
template<class T>
|
| 949 |
+
constexpr T bit_floor(T x) noexcept;
|
| 950 |
+
```
|
| 951 |
+
|
| 952 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 953 |
+
|
| 954 |
+
*Returns:* If `x == 0`, `0`; otherwise the maximal value `y` such that
|
| 955 |
+
`has_single_bit(y)` is `true` and `y <= x`.
|
| 956 |
+
|
| 957 |
+
``` cpp
|
| 958 |
+
template<class T>
|
| 959 |
+
constexpr T bit_width(T x) noexcept;
|
| 960 |
+
```
|
| 961 |
+
|
| 962 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 963 |
+
|
| 964 |
+
*Returns:* If `x == 0`, `0`; otherwise one plus the base-2 logarithm of
|
| 965 |
+
`x`, with any fractional part discarded.
|
| 966 |
+
|
| 967 |
+
### Rotating <a id="bit.rotate">[[bit.rotate]]</a>
|
| 968 |
+
|
| 969 |
+
In the following descriptions, let `N` denote
|
| 970 |
+
`numeric_limits<T>::digits`.
|
| 971 |
+
|
| 972 |
+
``` cpp
|
| 973 |
+
template<class T>
|
| 974 |
+
[[nodiscard]] constexpr T rotl(T x, int s) noexcept;
|
| 975 |
+
```
|
| 976 |
+
|
| 977 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 978 |
+
|
| 979 |
+
Let `r` be `s % N`.
|
| 980 |
+
|
| 981 |
+
*Returns:* If `r` is `0`, `x`; if `r` is positive,
|
| 982 |
+
`(x << r) | (x >> (N - r))`; if `r` is negative, `rotr(x, -r)`.
|
| 983 |
+
|
| 984 |
+
``` cpp
|
| 985 |
+
template<class T>
|
| 986 |
+
[[nodiscard]] constexpr T rotr(T x, int s) noexcept;
|
| 987 |
+
```
|
| 988 |
+
|
| 989 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 990 |
+
|
| 991 |
+
Let `r` be `s % N`.
|
| 992 |
+
|
| 993 |
+
*Returns:* If `r` is `0`, `x`; if `r` is positive,
|
| 994 |
+
`(x >> r) | (x << (N - r))`; if `r` is negative, `rotl(x, -r)`.
|
| 995 |
+
|
| 996 |
+
### Counting <a id="bit.count">[[bit.count]]</a>
|
| 997 |
+
|
| 998 |
+
In the following descriptions, let `N` denote
|
| 999 |
+
`numeric_limits<T>::digits`.
|
| 1000 |
+
|
| 1001 |
+
``` cpp
|
| 1002 |
+
template<class T>
|
| 1003 |
+
constexpr int countl_zero(T x) noexcept;
|
| 1004 |
+
```
|
| 1005 |
+
|
| 1006 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 1007 |
+
|
| 1008 |
+
*Returns:* The number of consecutive `0` bits in the value of `x`,
|
| 1009 |
+
starting from the most significant bit.
|
| 1010 |
+
|
| 1011 |
+
[*Note 1*: Returns `N` if `x == 0`. — *end note*]
|
| 1012 |
+
|
| 1013 |
+
``` cpp
|
| 1014 |
+
template<class T>
|
| 1015 |
+
constexpr int countl_one(T x) noexcept;
|
| 1016 |
+
```
|
| 1017 |
+
|
| 1018 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 1019 |
+
|
| 1020 |
+
*Returns:* The number of consecutive `1` bits in the value of `x`,
|
| 1021 |
+
starting from the most significant bit.
|
| 1022 |
+
|
| 1023 |
+
[*Note 2*: Returns `N` if
|
| 1024 |
+
`x == numeric_limits<T>::max()`. — *end note*]
|
| 1025 |
+
|
| 1026 |
+
``` cpp
|
| 1027 |
+
template<class T>
|
| 1028 |
+
constexpr int countr_zero(T x) noexcept;
|
| 1029 |
+
```
|
| 1030 |
+
|
| 1031 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 1032 |
+
|
| 1033 |
+
*Returns:* The number of consecutive `0` bits in the value of `x`,
|
| 1034 |
+
starting from the least significant bit.
|
| 1035 |
+
|
| 1036 |
+
[*Note 3*: Returns `N` if `x == 0`. — *end note*]
|
| 1037 |
+
|
| 1038 |
+
``` cpp
|
| 1039 |
+
template<class T>
|
| 1040 |
+
constexpr int countr_one(T x) noexcept;
|
| 1041 |
+
```
|
| 1042 |
+
|
| 1043 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 1044 |
+
|
| 1045 |
+
*Returns:* The number of consecutive `1` bits in the value of `x`,
|
| 1046 |
+
starting from the least significant bit.
|
| 1047 |
+
|
| 1048 |
+
[*Note 4*: Returns `N` if
|
| 1049 |
+
`x == numeric_limits<T>::max()`. — *end note*]
|
| 1050 |
+
|
| 1051 |
+
``` cpp
|
| 1052 |
+
template<class T>
|
| 1053 |
+
constexpr int popcount(T x) noexcept;
|
| 1054 |
+
```
|
| 1055 |
+
|
| 1056 |
+
*Constraints:* `T` is an unsigned integer type [[basic.fundamental]].
|
| 1057 |
+
|
| 1058 |
+
*Returns:* The number of `1` bits in the value of `x`.
|
| 1059 |
+
|
| 1060 |
+
### Endian <a id="bit.endian">[[bit.endian]]</a>
|
| 1061 |
+
|
| 1062 |
+
Two common methods of byte ordering in multibyte scalar types are
|
| 1063 |
+
big-endian and little-endian in the execution environment. Big-endian is
|
| 1064 |
+
a format for storage of binary data in which the most significant byte
|
| 1065 |
+
is placed first, with the rest in descending order. Little-endian is a
|
| 1066 |
+
format for storage of binary data in which the least significant byte is
|
| 1067 |
+
placed first, with the rest in ascending order. This subclause describes
|
| 1068 |
+
the endianness of the scalar types of the execution environment.
|
| 1069 |
+
|
| 1070 |
+
``` cpp
|
| 1071 |
+
enum class endian {
|
| 1072 |
+
little = see below,
|
| 1073 |
+
big = see below,
|
| 1074 |
+
native = see below
|
| 1075 |
+
};
|
| 1076 |
+
```
|
| 1077 |
+
|
| 1078 |
+
If all scalar types have size 1 byte, then all of `endian::little`,
|
| 1079 |
+
`endian::big`, and `endian::native` have the same value. Otherwise,
|
| 1080 |
+
`endian::little` is not equal to `endian::big`. If all scalar types are
|
| 1081 |
+
big-endian, `endian::native` is equal to `endian::big`. If all scalar
|
| 1082 |
+
types are little-endian, `endian::native` is equal to `endian::little`.
|
| 1083 |
+
Otherwise, `endian::native` is not equal to either `endian::big` or
|
| 1084 |
+
`endian::little`.
|
| 1085 |
+
|
| 1086 |
## Random number generation <a id="rand">[[rand]]</a>
|
| 1087 |
|
| 1088 |
This subclause defines a facility for generating (pseudo-)random
|
| 1089 |
numbers.
|
| 1090 |
|
| 1091 |
In addition to a few utilities, four categories of entities are
|
| 1092 |
described: *uniform random bit generators*, *random number engines*,
|
| 1093 |
*random number engine adaptors*, and *random number distributions*.
|
| 1094 |
+
These categorizations are applicable to types that meet the
|
| 1095 |
corresponding requirements, to objects instantiated from such types, and
|
| 1096 |
to templates producing such types when instantiated.
|
| 1097 |
|
| 1098 |
[*Note 1*: These entities are specified in such a way as to permit the
|
| 1099 |
binding of any uniform random bit generator object `e` as the argument
|
| 1100 |
to any random number distribution object `d`, thus producing a
|
| 1101 |
zero-argument function object such as given by
|
| 1102 |
`bind(d,e)`. — *end note*]
|
| 1103 |
|
| 1104 |
Each of the entities specified via this subclause has an associated
|
| 1105 |
+
arithmetic type [[basic.fundamental]] identified as `result_type`. With
|
| 1106 |
+
`T` as the `result_type` thus associated with such an entity, that
|
| 1107 |
entity is characterized:
|
| 1108 |
|
| 1109 |
+
- as *boolean* or equivalently as *boolean-valued*, if `T` is `bool`;
|
| 1110 |
+
- otherwise as *integral* or equivalently as *integer-valued*, if
|
| 1111 |
+
`numeric_limits<T>::is_integer` is `true`;
|
| 1112 |
+
- otherwise as *floating-point* or equivalently as *real-valued*.
|
| 1113 |
+
|
| 1114 |
If integer-valued, an entity may optionally be further characterized as
|
| 1115 |
*signed* or *unsigned*, according to `numeric_limits<T>::is_signed`.
|
| 1116 |
|
| 1117 |
Unless otherwise specified, all descriptions of calculations in this
|
| 1118 |
subclause use mathematical real numbers.
|
| 1119 |
|
| 1120 |
+
Throughout this subclause, the operators , , and \xor denote the
|
| 1121 |
+
respective conventional bitwise operations. Further:
|
| 1122 |
+
|
| 1123 |
+
- the operator \rightshift denotes a bitwise right shift with
|
| 1124 |
+
zero-valued bits appearing in the high bits of the result, and
|
| 1125 |
+
- the operator denotes a bitwise left shift with zero-valued bits
|
| 1126 |
+
appearing in the low bits of the result, and whose result is always
|
| 1127 |
+
taken modulo 2ʷ.
|
| 1128 |
+
|
| 1129 |
+
### Header `<random>` synopsis <a id="rand.synopsis">[[rand.synopsis]]</a>
|
| 1130 |
+
|
| 1131 |
+
``` cpp
|
| 1132 |
+
#include <initializer_list>
|
| 1133 |
+
|
| 1134 |
+
namespace std {
|
| 1135 |
+
// [rand.req.urng], uniform random bit generator requirements
|
| 1136 |
+
template<class G>
|
| 1137 |
+
concept uniform_random_bit_generator = see below;
|
| 1138 |
+
|
| 1139 |
+
// [rand.eng.lcong], class template linear_congruential_engine
|
| 1140 |
+
template<class UIntType, UIntType a, UIntType c, UIntType m>
|
| 1141 |
+
class linear_congruential_engine;
|
| 1142 |
+
|
| 1143 |
+
// [rand.eng.mers], class template mersenne_twister_engine
|
| 1144 |
+
template<class UIntType, size_t w, size_t n, size_t m, size_t r,
|
| 1145 |
+
UIntType a, size_t u, UIntType d, size_t s,
|
| 1146 |
+
UIntType b, size_t t,
|
| 1147 |
+
UIntType c, size_t l, UIntType f>
|
| 1148 |
+
class mersenne_twister_engine;
|
| 1149 |
+
|
| 1150 |
+
// [rand.eng.sub], class template subtract_with_carry_engine
|
| 1151 |
+
template<class UIntType, size_t w, size_t s, size_t r>
|
| 1152 |
+
class subtract_with_carry_engine;
|
| 1153 |
+
|
| 1154 |
+
// [rand.adapt.disc], class template discard_block_engine
|
| 1155 |
+
template<class Engine, size_t p, size_t r>
|
| 1156 |
+
class discard_block_engine;
|
| 1157 |
+
|
| 1158 |
+
// [rand.adapt.ibits], class template independent_bits_engine
|
| 1159 |
+
template<class Engine, size_t w, class UIntType>
|
| 1160 |
+
class independent_bits_engine;
|
| 1161 |
+
|
| 1162 |
+
// [rand.adapt.shuf], class template shuffle_order_engine
|
| 1163 |
+
template<class Engine, size_t k>
|
| 1164 |
+
class shuffle_order_engine;
|
| 1165 |
+
|
| 1166 |
+
// [rand.predef], engines and engine adaptors with predefined parameters
|
| 1167 |
+
using minstd_rand0 = see below;
|
| 1168 |
+
using minstd_rand = see below;
|
| 1169 |
+
using mt19937 = see below;
|
| 1170 |
+
using mt19937_64 = see below;
|
| 1171 |
+
using ranlux24_base = see below;
|
| 1172 |
+
using ranlux48_base = see below;
|
| 1173 |
+
using ranlux24 = see below;
|
| 1174 |
+
using ranlux48 = see below;
|
| 1175 |
+
using knuth_b = see below;
|
| 1176 |
+
|
| 1177 |
+
using default_random_engine = see below;
|
| 1178 |
+
|
| 1179 |
+
// [rand.device], class random_device
|
| 1180 |
+
class random_device;
|
| 1181 |
+
|
| 1182 |
+
// [rand.util.seedseq], class seed_seq
|
| 1183 |
+
class seed_seq;
|
| 1184 |
+
|
| 1185 |
+
// [rand.util.canonical], function template generate_canonical
|
| 1186 |
+
template<class RealType, size_t bits, class URBG>
|
| 1187 |
+
RealType generate_canonical(URBG& g);
|
| 1188 |
+
|
| 1189 |
+
// [rand.dist.uni.int], class template uniform_int_distribution
|
| 1190 |
+
template<class IntType = int>
|
| 1191 |
+
class uniform_int_distribution;
|
| 1192 |
+
|
| 1193 |
+
// [rand.dist.uni.real], class template uniform_real_distribution
|
| 1194 |
+
template<class RealType = double>
|
| 1195 |
+
class uniform_real_distribution;
|
| 1196 |
+
|
| 1197 |
+
// [rand.dist.bern.bernoulli], class bernoulli_distribution
|
| 1198 |
+
class bernoulli_distribution;
|
| 1199 |
+
|
| 1200 |
+
// [rand.dist.bern.bin], class template binomial_distribution
|
| 1201 |
+
template<class IntType = int>
|
| 1202 |
+
class binomial_distribution;
|
| 1203 |
+
|
| 1204 |
+
// [rand.dist.bern.geo], class template geometric_distribution
|
| 1205 |
+
template<class IntType = int>
|
| 1206 |
+
class geometric_distribution;
|
| 1207 |
+
|
| 1208 |
+
// [rand.dist.bern.negbin], class template negative_binomial_distribution
|
| 1209 |
+
template<class IntType = int>
|
| 1210 |
+
class negative_binomial_distribution;
|
| 1211 |
+
|
| 1212 |
+
// [rand.dist.pois.poisson], class template poisson_distribution
|
| 1213 |
+
template<class IntType = int>
|
| 1214 |
+
class poisson_distribution;
|
| 1215 |
+
|
| 1216 |
+
// [rand.dist.pois.exp], class template exponential_distribution
|
| 1217 |
+
template<class RealType = double>
|
| 1218 |
+
class exponential_distribution;
|
| 1219 |
+
|
| 1220 |
+
// [rand.dist.pois.gamma], class template gamma_distribution
|
| 1221 |
+
template<class RealType = double>
|
| 1222 |
+
class gamma_distribution;
|
| 1223 |
+
|
| 1224 |
+
// [rand.dist.pois.weibull], class template weibull_distribution
|
| 1225 |
+
template<class RealType = double>
|
| 1226 |
+
class weibull_distribution;
|
| 1227 |
+
|
| 1228 |
+
// [rand.dist.pois.extreme], class template extreme_value_distribution
|
| 1229 |
+
template<class RealType = double>
|
| 1230 |
+
class extreme_value_distribution;
|
| 1231 |
+
|
| 1232 |
+
// [rand.dist.norm.normal], class template normal_distribution
|
| 1233 |
+
template<class RealType = double>
|
| 1234 |
+
class normal_distribution;
|
| 1235 |
+
|
| 1236 |
+
// [rand.dist.norm.lognormal], class template lognormal_distribution
|
| 1237 |
+
template<class RealType = double>
|
| 1238 |
+
class lognormal_distribution;
|
| 1239 |
+
|
| 1240 |
+
// [rand.dist.norm.chisq], class template chi_squared_distribution
|
| 1241 |
+
template<class RealType = double>
|
| 1242 |
+
class chi_squared_distribution;
|
| 1243 |
+
|
| 1244 |
+
// [rand.dist.norm.cauchy], class template cauchy_distribution
|
| 1245 |
+
template<class RealType = double>
|
| 1246 |
+
class cauchy_distribution;
|
| 1247 |
+
|
| 1248 |
+
// [rand.dist.norm.f], class template fisher_f_distribution
|
| 1249 |
+
template<class RealType = double>
|
| 1250 |
+
class fisher_f_distribution;
|
| 1251 |
+
|
| 1252 |
+
// [rand.dist.norm.t], class template student_t_distribution
|
| 1253 |
+
template<class RealType = double>
|
| 1254 |
+
class student_t_distribution;
|
| 1255 |
+
|
| 1256 |
+
// [rand.dist.samp.discrete], class template discrete_distribution
|
| 1257 |
+
template<class IntType = int>
|
| 1258 |
+
class discrete_distribution;
|
| 1259 |
+
|
| 1260 |
+
// [rand.dist.samp.pconst], class template piecewise_constant_distribution
|
| 1261 |
+
template<class RealType = double>
|
| 1262 |
+
class piecewise_constant_distribution;
|
| 1263 |
+
|
| 1264 |
+
// [rand.dist.samp.plinear], class template piecewise_linear_distribution
|
| 1265 |
+
template<class RealType = double>
|
| 1266 |
+
class piecewise_linear_distribution;
|
| 1267 |
+
}
|
| 1268 |
+
```
|
| 1269 |
|
| 1270 |
### Requirements <a id="rand.req">[[rand.req]]</a>
|
| 1271 |
|
| 1272 |
#### General requirements <a id="rand.req.genl">[[rand.req.genl]]</a>
|
| 1273 |
|
| 1274 |
Throughout this subclause [[rand]], the effect of instantiating a
|
| 1275 |
template:
|
| 1276 |
|
| 1277 |
+
- that has a template type parameter named `Sseq` is undefined unless
|
| 1278 |
+
the corresponding template argument is cv-unqualified and meets the
|
| 1279 |
+
requirements of seed sequence [[rand.req.seedseq]].
|
| 1280 |
+
- that has a template type parameter named `URBG` is undefined unless
|
| 1281 |
+
the corresponding template argument is cv-unqualified and meets the
|
| 1282 |
+
requirements of uniform random bit generator [[rand.req.urng]].
|
| 1283 |
+
- that has a template type parameter named `Engine` is undefined unless
|
| 1284 |
+
the corresponding template argument is cv-unqualified and meets the
|
| 1285 |
+
requirements of random number engine [[rand.req.eng]].
|
| 1286 |
+
- that has a template type parameter named `RealType` is undefined
|
| 1287 |
+
unless the corresponding template argument is cv-unqualified and is
|
| 1288 |
+
one of `float`, `double`, or `long double`.
|
| 1289 |
+
- that has a template type parameter named `IntType` is undefined unless
|
| 1290 |
+
the corresponding template argument is cv-unqualified and is one of
|
| 1291 |
+
`short`, `int`, `long`, `long long`, `unsigned short`, `unsigned int`,
|
| 1292 |
+
`unsigned long`, or `unsigned long long`.
|
| 1293 |
+
- that has a template type parameter named `UIntType` is undefined
|
| 1294 |
+
unless the corresponding template argument is cv-unqualified and is
|
| 1295 |
+
one of `unsigned short`, `unsigned int`, `unsigned long`, or
|
| 1296 |
+
`unsigned long long`.
|
| 1297 |
+
|
| 1298 |
Throughout this subclause [[rand]], phrases of the form “`x` is an
|
| 1299 |
iterator of a specific kind” shall be interpreted as equivalent to the
|
| 1300 |
+
more formal requirement that “`x` is a value of a type meeting the
|
| 1301 |
requirements of the specified iterator type”.
|
| 1302 |
|
| 1303 |
Throughout this subclause [[rand]], any constructor that can be called
|
| 1304 |
+
with a single argument and that meets a requirement specified in this
|
| 1305 |
+
subclause shall be declared `explicit`.
|
| 1306 |
|
| 1307 |
#### Seed sequence requirements <a id="rand.req.seedseq">[[rand.req.seedseq]]</a>
|
| 1308 |
|
| 1309 |
A *seed sequence* is an object that consumes a sequence of
|
| 1310 |
integer-valued data and produces a requested number of unsigned integer
|
|
|
|
| 1313 |
[*Note 1*: Such an object provides a mechanism to avoid replication of
|
| 1314 |
streams of random variates. This can be useful, for example, in
|
| 1315 |
applications requiring large numbers of random number
|
| 1316 |
engines. — *end note*]
|
| 1317 |
|
| 1318 |
+
A class `S` meets the requirements of a seed sequence if the expressions
|
| 1319 |
+
shown in [[rand.req.seedseq]] are valid and have the indicated
|
| 1320 |
+
semantics, and if `S` also meets all other requirements of this
|
| 1321 |
+
subclause [[rand.req.seedseq]]. In that Table and throughout this
|
| 1322 |
+
subclause:
|
| 1323 |
+
|
| 1324 |
+
- `T` is the type named by `S`’s associated `result_type`;
|
| 1325 |
+
- `q` is a value of `S` and `r` is a possibly const value of `S`;
|
| 1326 |
+
- `ib` and `ie` are input iterators with an unsigned integer
|
| 1327 |
+
`value_type` of at least 32 bits;
|
| 1328 |
+
- `rb` and `re` are mutable random access iterators with an unsigned
|
| 1329 |
+
integer `value_type` of at least 32 bits;
|
| 1330 |
+
- `ob` is an output iterator; and
|
| 1331 |
+
- `il` is a value of `initializer_list<T>`.
|
| 1332 |
|
| 1333 |
#### Uniform random bit generator requirements <a id="rand.req.urng">[[rand.req.urng]]</a>
|
| 1334 |
|
| 1335 |
A *uniform random bit generator* `g` of type `G` is a function object
|
| 1336 |
returning unsigned integer values such that each value in the range of
|
| 1337 |
possible results has (ideally) equal probability of being returned.
|
| 1338 |
|
| 1339 |
[*Note 1*: The degree to which `g`’s results approximate the ideal is
|
| 1340 |
often determined statistically. — *end note*]
|
| 1341 |
|
| 1342 |
+
``` cpp
|
| 1343 |
+
template<class G>
|
| 1344 |
+
concept uniform_random_bit_generator =
|
| 1345 |
+
invocable<G&> && unsigned_integral<invoke_result_t<G&>> &&
|
| 1346 |
+
requires {
|
| 1347 |
+
{ G::min() } -> same_as<invoke_result_t<G&>>;
|
| 1348 |
+
{ G::max() } -> same_as<invoke_result_t<G&>>;
|
| 1349 |
+
requires bool_constant<(G::min() < G::max())>::value;
|
| 1350 |
+
};
|
| 1351 |
+
```
|
| 1352 |
|
| 1353 |
+
Let `g` be an object of type `G`. `G` models
|
| 1354 |
+
`uniform_random_bit_generator` only if
|
| 1355 |
+
|
| 1356 |
+
- `G::min() <= g()`,
|
| 1357 |
+
- `g() <= G::max()`, and
|
| 1358 |
+
- `g()` has amortized constant complexity.
|
| 1359 |
+
|
| 1360 |
+
A class `G` meets the *uniform random bit generator* requirements if `G`
|
| 1361 |
+
models `uniform_random_bit_generator`, `invoke_result_t<G&>` is an
|
| 1362 |
+
unsigned integer type [[basic.fundamental]], and `G` provides a nested
|
| 1363 |
+
*typedef-name* `result_type` that denotes the same type as
|
| 1364 |
+
`invoke_result_t<G&>`.
|
| 1365 |
|
| 1366 |
#### Random number engine requirements <a id="rand.req.eng">[[rand.req.eng]]</a>
|
| 1367 |
|
| 1368 |
A *random number engine* (commonly shortened to *engine*) `e` of type
|
| 1369 |
`E` is a uniform random bit generator that additionally meets the
|
| 1370 |
requirements (e.g., for seeding and for input/output) specified in this
|
| 1371 |
+
subclause.
|
| 1372 |
|
| 1373 |
At any given time, `e` has a state eᵢ for some integer i ≥ 0. Upon
|
| 1374 |
construction, `e` has an initial state e₀. An engine’s state may be
|
| 1375 |
established via a constructor, a `seed` function, assignment, or a
|
| 1376 |
suitable `operator>>`.
|
| 1377 |
|
| 1378 |
`E`’s specification shall define:
|
| 1379 |
|
| 1380 |
+
- the size of `E`’s state in multiples of the size of `result_type`,
|
| 1381 |
+
given as an integral constant expression;
|
| 1382 |
+
- the *transition algorithm* TA by which `e`’s state eᵢ is advanced to
|
| 1383 |
+
its *successor state* eᵢ₊₁; and
|
| 1384 |
+
- the *generation algorithm* GA by which an engine’s state is mapped to
|
| 1385 |
+
a value of type `result_type`.
|
| 1386 |
+
|
| 1387 |
+
A class `E` that meets the requirements of a uniform random bit
|
| 1388 |
+
generator [[rand.req.urng]] also meets the requirements of a *random
|
| 1389 |
+
number engine* if the expressions shown in [[rand.req.eng]] are valid
|
| 1390 |
+
and have the indicated semantics, and if `E` also meets all other
|
| 1391 |
+
requirements of this subclause [[rand.req.eng]]. In that Table and
|
| 1392 |
+
throughout this subclause:
|
| 1393 |
+
|
| 1394 |
+
- `T` is the type named by `E`’s associated `result_type`;
|
| 1395 |
+
- `e` is a value of `E`, `v` is an lvalue of `E`, `x` and `y` are
|
| 1396 |
+
(possibly `const`) values of `E`;
|
| 1397 |
+
- `s` is a value of `T`;
|
| 1398 |
+
- `q` is an lvalue meeting the requirements of a seed sequence
|
| 1399 |
+
[[rand.req.seedseq]];
|
| 1400 |
+
- `z` is a value of type `unsigned long long`;
|
| 1401 |
+
- `os` is an lvalue of the type of some class template specialization
|
| 1402 |
+
`basic_ostream<charT,` `traits>`; and
|
| 1403 |
+
- `is` is an lvalue of the type of some class template specialization
|
| 1404 |
+
`basic_istream<charT,` `traits>`;
|
| 1405 |
+
|
| 1406 |
+
where `charT` and `traits` are constrained according to [[strings]] and
|
| 1407 |
+
[[input.output]].
|
| 1408 |
+
|
| 1409 |
+
`E` shall meet the *Cpp17CopyConstructible* (
|
| 1410 |
+
[[cpp17.copyconstructible]]) and *Cpp17CopyAssignable* (
|
| 1411 |
+
[[cpp17.copyassignable]]) requirements. These operations shall each be
|
| 1412 |
+
of complexity no worse than 𝑂(\text{size of state}).
|
| 1413 |
|
| 1414 |
#### Random number engine adaptor requirements <a id="rand.req.adapt">[[rand.req.adapt]]</a>
|
| 1415 |
|
| 1416 |
A *random number engine adaptor* (commonly shortened to *adaptor*) `a`
|
| 1417 |
of type `A` is a random number engine that takes values produced by some
|
|
|
|
| 1466 |
template<class Sseq> void seed(Sseq& q);
|
| 1467 |
```
|
| 1468 |
|
| 1469 |
*Effects:* With `b` as the base engine, invokes `b.seed(q)`.
|
| 1470 |
|
| 1471 |
+
`A` shall also meet the following additional requirements:
|
| 1472 |
+
|
| 1473 |
+
- The complexity of each function shall not exceed the complexity of the
|
| 1474 |
+
corresponding function applied to the base engine.
|
| 1475 |
+
- The state of `A` shall include the state of its base engine. The size
|
| 1476 |
+
of `A`’s state shall be no less than the size of the base engine.
|
| 1477 |
+
- Copying `A`’s state (e.g., during copy construction or copy
|
| 1478 |
+
assignment) shall include copying the state of the base engine of `A`.
|
| 1479 |
+
- The textual representation of `A` shall include the textual
|
| 1480 |
+
representation of its base engine.
|
| 1481 |
|
| 1482 |
#### Random number distribution requirements <a id="rand.req.dist">[[rand.req.dist]]</a>
|
| 1483 |
|
| 1484 |
A *random number distribution* (commonly shortened to *distribution*)
|
| 1485 |
`d` of type `D` is a function object returning values that are
|
|
|
|
| 1494 |
context by writing, for example, p(z | a,b) or P(zᵢ | a,b), to name
|
| 1495 |
specific parameters, or by writing, for example, p(z |{`p`}) or
|
| 1496 |
P(zᵢ |{`p`}), to denote a distribution’s parameters `p` taken as a
|
| 1497 |
whole.
|
| 1498 |
|
| 1499 |
+
A class `D` meets the requirements of a *random number distribution* if
|
| 1500 |
+
the expressions shown in [[rand.req.dist]] are valid and have the
|
| 1501 |
+
indicated semantics, and if `D` and its associated types also meet all
|
| 1502 |
+
other requirements of this subclause [[rand.req.dist]]. In that Table
|
| 1503 |
+
and throughout this subclause,
|
| 1504 |
|
| 1505 |
+
- `T` is the type named by `D`’s associated `result_type`;
|
| 1506 |
+
- `P` is the type named by `D`’s associated `param_type`;
|
| 1507 |
+
- `d` is a value of `D`, and `x` and `y` are (possibly `const`) values
|
| 1508 |
+
of `D`;
|
| 1509 |
+
- `glb` and `lub` are values of `T` respectively corresponding to the
|
| 1510 |
+
greatest lower bound and the least upper bound on the values
|
| 1511 |
+
potentially returned by `d`’s `operator()`, as determined by the
|
| 1512 |
+
current values of `d`’s parameters;
|
| 1513 |
+
- `p` is a (possibly `const`) value of `P`;
|
| 1514 |
+
- `g`, `g1`, and `g2` are lvalues of a type meeting the requirements of
|
| 1515 |
+
a uniform random bit generator [[rand.req.urng]];
|
| 1516 |
+
- `os` is an lvalue of the type of some class template specialization
|
| 1517 |
+
`basic_ostream<charT,` `traits>`; and
|
| 1518 |
+
- `is` is an lvalue of the type of some class template specialization
|
| 1519 |
+
`basic_istream<charT,` `traits>`;
|
| 1520 |
|
| 1521 |
+
where `charT` and `traits` are constrained according to [[strings]] and
|
| 1522 |
+
[[input.output]].
|
| 1523 |
+
|
| 1524 |
+
`D` shall meet the *Cpp17CopyConstructible* (
|
| 1525 |
+
[[cpp17.copyconstructible]]) and *Cpp17CopyAssignable* (
|
| 1526 |
+
[[cpp17.copyassignable]]) requirements.
|
| 1527 |
|
| 1528 |
The sequence of numbers produced by repeated invocations of `d(g)` shall
|
| 1529 |
be independent of any invocation of `os << d` or of any `const` member
|
| 1530 |
function of `D` between any of the invocations `d(g)`.
|
| 1531 |
|
|
|
|
| 1538 |
It is unspecified whether `D::param_type` is declared as a (nested)
|
| 1539 |
`class` or via a `typedef`. In this subclause [[rand]], declarations of
|
| 1540 |
`D::param_type` are in the form of `typedef`s for convenience of
|
| 1541 |
exposition only.
|
| 1542 |
|
| 1543 |
+
`P` shall meet the *Cpp17CopyConstructible* (
|
| 1544 |
+
[[cpp17.copyconstructible]]), *Cpp17CopyAssignable* (
|
| 1545 |
+
[[cpp17.copyassignable]]), and *Cpp17EqualityComparable* (
|
| 1546 |
+
[[cpp17.equalitycomparable]]) requirements.
|
| 1547 |
|
| 1548 |
For each of the constructors of `D` taking arguments corresponding to
|
| 1549 |
parameters of the distribution, `P` shall have a corresponding
|
| 1550 |
constructor subject to the same requirements and taking arguments
|
| 1551 |
identical in number, type, and default values. Moreover, for each of the
|
|
|
|
| 1557 |
|
| 1558 |
``` cpp
|
| 1559 |
using distribution_type = D;
|
| 1560 |
```
|
| 1561 |
|
|
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|
| 1562 |
### Random number engine class templates <a id="rand.eng">[[rand.eng]]</a>
|
| 1563 |
|
| 1564 |
+
Each type instantiated from a class template specified in this
|
| 1565 |
+
subclause [[rand.eng]] meets the requirements of a random number engine
|
| 1566 |
+
[[rand.req.eng]] type.
|
| 1567 |
|
| 1568 |
Except where specified otherwise, the complexity of each function
|
| 1569 |
+
specified in this subclause [[rand.eng]] is constant.
|
| 1570 |
|
| 1571 |
+
Except where specified otherwise, no function described in this
|
| 1572 |
+
subclause [[rand.eng]] throws an exception.
|
| 1573 |
|
| 1574 |
+
Every function described in this subclause [[rand.eng]] that has a
|
| 1575 |
function parameter `q` of type `Sseq&` for a template type parameter
|
| 1576 |
named `Sseq` that is different from type `seed_seq` throws what and when
|
| 1577 |
the invocation of `q.generate` throws.
|
| 1578 |
|
| 1579 |
+
Descriptions are provided in this subclause [[rand.eng]] only for
|
| 1580 |
+
engine operations that are not described in [[rand.req.eng]] or for
|
| 1581 |
+
operations where there is additional semantic information. In
|
| 1582 |
+
particular, declarations for copy constructors, for copy assignment
|
| 1583 |
+
operators, for streaming operators, and for equality and inequality
|
| 1584 |
+
operators are not shown in the synopses.
|
| 1585 |
|
| 1586 |
+
Each template specified in this subclause [[rand.eng]] requires one or
|
| 1587 |
more relationships, involving the value(s) of its non-type template
|
| 1588 |
parameter(s), to hold. A program instantiating any of these templates is
|
| 1589 |
ill-formed if any such required relationship fails to hold.
|
| 1590 |
|
| 1591 |
For every random number engine and for every random number engine
|
| 1592 |
+
adaptor `X` defined in this subclause [[rand.eng]] and in subclause
|
| 1593 |
[[rand.adapt]]:
|
| 1594 |
|
| 1595 |
- if the constructor
|
| 1596 |
``` cpp
|
| 1597 |
template<class Sseq> explicit X(Sseq& q);
|
|
|
|
| 1635 |
static constexpr result_type min() { return c == 0u ? 1u: 0u; }
|
| 1636 |
static constexpr result_type max() { return m - 1u; }
|
| 1637 |
static constexpr result_type default_seed = 1u;
|
| 1638 |
|
| 1639 |
// constructors and seeding functions
|
| 1640 |
+
linear_congruential_engine() : linear_congruential_engine(default_seed) {}
|
| 1641 |
+
explicit linear_congruential_engine(result_type s);
|
| 1642 |
template<class Sseq> explicit linear_congruential_engine(Sseq& q);
|
| 1643 |
void seed(result_type s = default_seed);
|
| 1644 |
template<class Sseq> void seed(Sseq& q);
|
| 1645 |
|
| 1646 |
// generating functions
|
|
|
|
| 1648 |
void discard(unsigned long long z);
|
| 1649 |
};
|
| 1650 |
```
|
| 1651 |
|
| 1652 |
If the template parameter `m` is 0, the modulus m used throughout this
|
| 1653 |
+
subclause [[rand.eng.lcong]] is `numeric_limits<result_type>::max()`
|
| 1654 |
+
plus 1.
|
| 1655 |
|
| 1656 |
[*Note 1*: m need not be representable as a value of type
|
| 1657 |
`result_type`. — *end note*]
|
| 1658 |
|
| 1659 |
If the template parameter `m` is not 0, the following relations shall
|
| 1660 |
hold: `a < m` and `c < m`.
|
| 1661 |
|
| 1662 |
The textual representation consists of the value of xᵢ.
|
| 1663 |
|
| 1664 |
``` cpp
|
| 1665 |
+
explicit linear_congruential_engine(result_type s);
|
| 1666 |
```
|
| 1667 |
|
| 1668 |
+
*Effects:* If c mod m is 0 and `s` mod m is 0, sets the engine’s
|
| 1669 |
+
state to 1, otherwise sets the engine’s state to `s` mod m.
|
|
|
|
| 1670 |
|
| 1671 |
``` cpp
|
| 1672 |
template<class Sseq> explicit linear_congruential_engine(Sseq& q);
|
| 1673 |
```
|
| 1674 |
|
| 1675 |
+
*Effects:* With $k = \left\lceil \frac{\log_2 m}{32} \right\rceil$ and a
|
| 1676 |
+
an array (or equivalent) of length k + 3, invokes
|
| 1677 |
+
`q.generate(`a + 0`, `a + k + 3`)` and then computes
|
| 1678 |
+
$S = \left(\sum_{j = 0}^{k - 1} a_{j + 3} \cdot 2^{32j} \right) \bmod m$.
|
| 1679 |
+
If c mod m is 0 and S is 0, sets the engine’s state to 1, else sets
|
| 1680 |
+
the engine’s state to S.
|
|
|
|
|
|
|
| 1681 |
|
| 1682 |
#### Class template `mersenne_twister_engine` <a id="rand.eng.mers">[[rand.eng.mers]]</a>
|
| 1683 |
|
| 1684 |
A `mersenne_twister_engine` random number engine[^2] produces unsigned
|
| 1685 |
integer random numbers in the closed interval [0,2ʷ-1]. The state xᵢ of
|
|
|
|
| 1689 |
|
| 1690 |
The transition algorithm employs a twisted generalized feedback shift
|
| 1691 |
register defined by shift values n and m, a twist value r, and a
|
| 1692 |
conditional xor-mask a. To improve the uniformity of the result, the
|
| 1693 |
bits of the raw shift register are additionally *tempered* (i.e.,
|
| 1694 |
+
scrambled) according to a bit-scrambling matrix defined by values u, d,
|
| 1695 |
+
s, b, t, c, and ℓ.
|
| 1696 |
|
| 1697 |
The state transition is performed as follows:
|
| 1698 |
|
| 1699 |
+
- Concatenate the upper w-r bits of Xᵢ₋ₙ with the lower r bits of
|
| 1700 |
+
$X_{i+1-n}$ to obtain an unsigned integer value Y.
|
| 1701 |
+
- With $\alpha = a \cdot (Y \bitand 1)$, set Xᵢ to
|
| 1702 |
+
$X_{i+m-n} \xor (Y \rightshift 1) \xor \alpha$.
|
| 1703 |
+
|
| 1704 |
The sequence X is initialized with the help of an initialization
|
| 1705 |
multiplier f.
|
| 1706 |
|
| 1707 |
The generation algorithm determines the unsigned integer values
|
| 1708 |
z₁, z₂, z₃, z₄ as follows, then delivers z₄ as its result:
|
| 1709 |
|
| 1710 |
+
- Let $z_1 = X_i \xor \bigl(( X_i \rightshift u ) \bitand d\bigr)$.
|
| 1711 |
+
- Let $z_2 = z_1 \xor \bigl( (z_1 \leftshift{w} s) \bitand b \bigr)$.
|
| 1712 |
+
- Let $z_3 = z_2 \xor \bigl( (z_2 \leftshift{w} t) \bitand c \bigr)$.
|
| 1713 |
+
- Let $z_4 = z_3 \xor ( z_3 \rightshift \ell )$.
|
| 1714 |
+
|
| 1715 |
``` cpp
|
| 1716 |
template<class UIntType, size_t w, size_t n, size_t m, size_t r,
|
| 1717 |
UIntType a, size_t u, UIntType d, size_t s,
|
| 1718 |
UIntType b, size_t t,
|
| 1719 |
UIntType c, size_t l, UIntType f>
|
|
|
|
| 1739 |
static constexpr result_type min() { return 0; }
|
| 1740 |
static constexpr result_type max() { return 2^w - 1; }
|
| 1741 |
static constexpr result_type default_seed = 5489u;
|
| 1742 |
|
| 1743 |
// constructors and seeding functions
|
| 1744 |
+
mersenne_twister_engine() : mersenne_twister_engine(default_seed) {}
|
| 1745 |
+
explicit mersenne_twister_engine(result_type value);
|
| 1746 |
template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
|
| 1747 |
void seed(result_type value = default_seed);
|
| 1748 |
template<class Sseq> void seed(Sseq& q);
|
| 1749 |
|
| 1750 |
// generating functions
|
|
|
|
| 1758 |
`w <= numeric_limits<UIntType>::digits`, `a <= (1u<<w) - 1u`,
|
| 1759 |
`b <= (1u<<w) - 1u`, `c <= (1u<<w) - 1u`, `d <= (1u<<w) - 1u`, and
|
| 1760 |
`f <= (1u<<w) - 1u`.
|
| 1761 |
|
| 1762 |
The textual representation of xᵢ consists of the values of
|
| 1763 |
+
$X_{i - n}, \dotsc, X_{i - 1}$, in that order.
|
| 1764 |
|
| 1765 |
``` cpp
|
| 1766 |
+
explicit mersenne_twister_engine(result_type value);
|
| 1767 |
```
|
| 1768 |
|
| 1769 |
+
*Effects:* Sets X₋ₙ to `value` mod 2ʷ. Then, iteratively for
|
| 1770 |
+
i = 1 - n, …, -1, sets Xᵢ to $$%
|
| 1771 |
\bigl[f \cdot
|
| 1772 |
\bigl(X_{i-1} \xor \bigl(X_{i-1} \rightshift (w-2)\bigr)
|
| 1773 |
\bigr)
|
| 1774 |
+ i \bmod n
|
| 1775 |
\bigr] \bmod 2^w
|
|
|
|
| 1779 |
|
| 1780 |
``` cpp
|
| 1781 |
template<class Sseq> explicit mersenne_twister_engine(Sseq& q);
|
| 1782 |
```
|
| 1783 |
|
| 1784 |
+
*Effects:* With k = ⌈ w / 32 ⌉ and a an array (or equivalent) of length
|
| 1785 |
+
n ⋅ k, invokes `q.generate(`a+0`, `a+n ⋅ k`)` and then, iteratively for
|
| 1786 |
+
i = -n,…,-1, sets Xᵢ to
|
|
|
|
| 1787 |
$\left(\sum_{j=0}^{k-1}a_{k(i+n)+j} \cdot 2^{32j} \right) \bmod 2^w$.
|
| 1788 |
Finally, if the most significant w-r bits of X₋ₙ are zero, and if each
|
| 1789 |
of the other resulting Xᵢ is 0, changes X₋ₙ to 2ʷ⁻¹.
|
| 1790 |
|
| 1791 |
#### Class template `subtract_with_carry_engine` <a id="rand.eng.sub">[[rand.eng.sub]]</a>
|
|
|
|
| 1799 |
additionally consists of an integer c (known as the *carry*) whose value
|
| 1800 |
is either 0 or 1.
|
| 1801 |
|
| 1802 |
The state transition is performed as follows:
|
| 1803 |
|
| 1804 |
+
- Let Y = Xᵢ₋ₛ - Xᵢ₋ᵣ - c.
|
| 1805 |
+
- Set Xᵢ to y = Y mod m. Set c to 1 if Y < 0, otherwise set c to 0.
|
| 1806 |
+
|
| 1807 |
[*Note 1*: This algorithm corresponds to a modular linear function of
|
| 1808 |
the form TA(xᵢ) = (a ⋅ xᵢ) mod b, where b is of the form mʳ - mˢ + 1
|
| 1809 |
and a = b - (b - 1) / m. — *end note*]
|
| 1810 |
|
| 1811 |
The generation algorithm is given by GA(xᵢ) = y, where y is the value
|
|
|
|
| 1825 |
static constexpr result_type min() { return 0; }
|
| 1826 |
static constexpr result_type max() { return m - 1; }
|
| 1827 |
static constexpr result_type default_seed = 19780503u;
|
| 1828 |
|
| 1829 |
// constructors and seeding functions
|
| 1830 |
+
subtract_with_carry_engine() : subtract_with_carry_engine(default_seed) {}
|
| 1831 |
+
explicit subtract_with_carry_engine(result_type value);
|
| 1832 |
template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
|
| 1833 |
void seed(result_type value = default_seed);
|
| 1834 |
template<class Sseq> void seed(Sseq& q);
|
| 1835 |
|
| 1836 |
// generating functions
|
|
|
|
| 1844 |
|
| 1845 |
The textual representation consists of the values of Xᵢ₋ᵣ, …, Xᵢ₋₁, in
|
| 1846 |
that order, followed by c.
|
| 1847 |
|
| 1848 |
``` cpp
|
| 1849 |
+
explicit subtract_with_carry_engine(result_type value);
|
| 1850 |
```
|
| 1851 |
|
| 1852 |
+
*Effects:* Sets the values of X₋ᵣ, …, X₋₁, in that order, as specified
|
| 1853 |
+
below. If X₋₁ is then 0, sets c to 1; otherwise sets c to 0.
|
|
|
|
| 1854 |
|
| 1855 |
To set the values Xₖ, first construct `e`, a
|
| 1856 |
`linear_congruential_engine` object, as if by the following definition:
|
| 1857 |
|
| 1858 |
``` cpp
|
|
|
|
| 1868 |
|
| 1869 |
``` cpp
|
| 1870 |
template<class Sseq> explicit subtract_with_carry_engine(Sseq& q);
|
| 1871 |
```
|
| 1872 |
|
| 1873 |
+
*Effects:* With k = ⌈ w / 32 ⌉ and a an array (or equivalent) of length
|
| 1874 |
+
r ⋅ k, invokes `q.generate(`a + 0`, `a + r ⋅ k`)` and then, iteratively
|
| 1875 |
+
for i = -r, …, -1, sets Xᵢ to
|
|
|
|
| 1876 |
$\left(\sum_{j=0}^{k-1}a_{k(i+r)+j} \cdot 2^{32j} \right) \bmod m$. If
|
| 1877 |
X₋₁ is then 0, sets c to 1; otherwise sets c to 0.
|
| 1878 |
|
| 1879 |
### Random number engine adaptor class templates <a id="rand.adapt">[[rand.adapt]]</a>
|
| 1880 |
|
| 1881 |
#### In general <a id="rand.adapt.general">[[rand.adapt.general]]</a>
|
| 1882 |
|
| 1883 |
+
Each type instantiated from a class template specified in this
|
| 1884 |
+
subclause [[rand.adapt]] meets the requirements of a random number
|
| 1885 |
+
engine adaptor [[rand.req.adapt]] type.
|
| 1886 |
|
| 1887 |
Except where specified otherwise, the complexity of each function
|
| 1888 |
+
specified in this subclause [[rand.adapt]] is constant.
|
| 1889 |
|
| 1890 |
+
Except where specified otherwise, no function described in this
|
| 1891 |
+
subclause [[rand.adapt]] throws an exception.
|
| 1892 |
|
| 1893 |
+
Every function described in this subclause [[rand.adapt]] that has a
|
| 1894 |
function parameter `q` of type `Sseq&` for a template type parameter
|
| 1895 |
named `Sseq` that is different from type `seed_seq` throws what and when
|
| 1896 |
the invocation of `q.generate` throws.
|
| 1897 |
|
| 1898 |
+
Descriptions are provided in this subclause [[rand.adapt]] only for
|
| 1899 |
+
adaptor operations that are not described in subclause
|
| 1900 |
+
[[rand.req.adapt]] or for operations where there is additional semantic
|
| 1901 |
+
information. In particular, declarations for copy constructors, for copy
|
| 1902 |
+
assignment operators, for streaming operators, and for equality and
|
| 1903 |
+
inequality operators are not shown in the synopses.
|
| 1904 |
|
| 1905 |
+
Each template specified in this subclause [[rand.adapt]] requires one
|
| 1906 |
+
or more relationships, involving the value(s) of its non-type template
|
| 1907 |
parameter(s), to hold. A program instantiating any of these templates is
|
| 1908 |
ill-formed if any such required relationship fails to hold.
|
| 1909 |
|
| 1910 |
#### Class template `discard_block_engine` <a id="rand.adapt.disc">[[rand.adapt.disc]]</a>
|
| 1911 |
|
|
|
|
| 1963 |
The following relations shall hold: `0 < r` and `r <= p`.
|
| 1964 |
|
| 1965 |
The textual representation consists of the textual representation of `e`
|
| 1966 |
followed by the value of `n`.
|
| 1967 |
|
| 1968 |
+
In addition to its behavior pursuant to subclause [[rand.req.adapt]],
|
| 1969 |
each constructor that is not a copy constructor sets `n` to 0.
|
| 1970 |
|
| 1971 |
#### Class template `independent_bits_engine` <a id="rand.adapt.ibits">[[rand.adapt.ibits]]</a>
|
| 1972 |
|
| 1973 |
An `independent_bits_engine` random number engine adaptor combines
|
|
|
|
| 1978 |
e’s state.
|
| 1979 |
|
| 1980 |
The transition and generation algorithms are described in terms of the
|
| 1981 |
following integral constants:
|
| 1982 |
|
| 1983 |
+
- Let R = `e.max() - e.min() + 1` and m = ⌊ log₂ R ⌋.
|
| 1984 |
+
- With n as determined below, let w₀ = ⌊ w / n ⌋, n₀ = n - w mod n,
|
| 1985 |
+
$y_0 = 2^{w_0} \left\lfloor R / 2^{w_0} \right\rfloor$, and
|
| 1986 |
+
$y_1 = 2^{w_0 + 1} \left\lfloor R / 2^{w_0 + 1} \right\rfloor$.
|
| 1987 |
+
- Let n = ⌈ w / m ⌉ if and only if the relation R - y₀ ≤ ⌊ y₀ / n ⌋
|
| 1988 |
+
holds as a result. Otherwise let n = 1 + ⌈ w / m ⌉.
|
| 1989 |
+
|
| 1990 |
[*Note 1*: The relation w = n₀ w₀ + (n - n₀)(w₀ + 1) always
|
| 1991 |
holds. — *end note*]
|
| 1992 |
|
| 1993 |
The transition algorithm is carried out by invoking `e()` as often as
|
| 1994 |
needed to obtain n₀ values less than y₀ + `e.min()` and n - n₀ values
|
|
|
|
| 2060 |
size of the state is the size of e’s state plus k + 1.
|
| 2061 |
|
| 2062 |
The transition algorithm permutes the values produced by e. The state
|
| 2063 |
transition is performed as follows:
|
| 2064 |
|
| 2065 |
+
- Calculate an integer $j = \left\lfloor \frac{k \cdot (Y - e_{\min})}
|
| 2066 |
+
{e_{\max} - e_{\min} +1}
|
| 2067 |
+
\right\rfloor$ .
|
| 2068 |
+
- Set Y to Vⱼ and then set Vⱼ to `e()`.
|
| 2069 |
+
|
| 2070 |
The generation algorithm yields the last value of `Y` produced while
|
| 2071 |
advancing `e`’s state as described above.
|
| 2072 |
|
| 2073 |
``` cpp
|
| 2074 |
template<class Engine, size_t k>
|
|
|
|
| 2109 |
The following relation shall hold: `0 < k`.
|
| 2110 |
|
| 2111 |
The textual representation consists of the textual representation of
|
| 2112 |
`e`, followed by the `k` values of V, followed by the value of Y.
|
| 2113 |
|
| 2114 |
+
In addition to its behavior pursuant to subclause [[rand.req.adapt]],
|
| 2115 |
each constructor that is not a copy constructor initializes
|
| 2116 |
`V[0]`, …, `V[k-1]` and Y, in that order, with values returned by
|
| 2117 |
successive invocations of `e()`.
|
| 2118 |
|
| 2119 |
### Engines and engine adaptors with predefined parameters <a id="rand.predef">[[rand.predef]]</a>
|
| 2120 |
|
| 2121 |
``` cpp
|
| 2122 |
using minstd_rand0 =
|
| 2123 |
+
linear_congruential_engine<uint_fast32_t, 16'807, 0, 2'147'483'647>;
|
| 2124 |
```
|
| 2125 |
|
| 2126 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2127 |
+
default-constructed object of type `minstd_rand0` produces the value
|
| 2128 |
+
1043618065.
|
| 2129 |
|
| 2130 |
``` cpp
|
| 2131 |
using minstd_rand =
|
| 2132 |
+
linear_congruential_engine<uint_fast32_t, 48'271, 0, 2'147'483'647>;
|
| 2133 |
```
|
| 2134 |
|
| 2135 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2136 |
+
default-constructed object of type `minstd_rand` produces the value
|
| 2137 |
399268537.
|
| 2138 |
|
| 2139 |
``` cpp
|
| 2140 |
using mt19937 =
|
| 2141 |
+
mersenne_twister_engine<uint_fast32_t, 32, 624, 397, 31,
|
| 2142 |
+
0x9908'b0df, 11, 0xffff'ffff, 7, 0x9d2c'5680, 15, 0xefc6'0000, 18, 1'812'433'253>;
|
| 2143 |
```
|
| 2144 |
|
| 2145 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2146 |
+
default-constructed object of type `mt19937` produces the value
|
| 2147 |
4123659995.
|
| 2148 |
|
| 2149 |
``` cpp
|
| 2150 |
using mt19937_64 =
|
| 2151 |
+
mersenne_twister_engine<uint_fast64_t, 64, 312, 156, 31,
|
| 2152 |
+
0xb502'6f5a'a966'19e9, 29, 0x5555'5555'5555'5555, 17,
|
| 2153 |
+
0x71d6'7fff'eda6'0000, 37, 0xfff7'eee0'0000'0000, 43, 6'364'136'223'846'793'005>;
|
|
|
|
|
|
|
|
|
|
| 2154 |
```
|
| 2155 |
|
| 2156 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2157 |
+
default-constructed object of type `mt19937_64` produces the value
|
| 2158 |
9981545732273789042.
|
| 2159 |
|
| 2160 |
``` cpp
|
| 2161 |
using ranlux24_base =
|
| 2162 |
subtract_with_carry_engine<uint_fast32_t, 24, 10, 24>;
|
| 2163 |
```
|
| 2164 |
|
| 2165 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2166 |
+
default-constructed object of type `ranlux24_base` produces the value
|
| 2167 |
+
7937952.
|
| 2168 |
|
| 2169 |
``` cpp
|
| 2170 |
using ranlux48_base =
|
| 2171 |
subtract_with_carry_engine<uint_fast64_t, 48, 5, 12>;
|
| 2172 |
```
|
| 2173 |
|
| 2174 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2175 |
+
default-constructed object of type `ranlux48_base` produces the value
|
| 2176 |
+
61839128582725.
|
| 2177 |
|
| 2178 |
``` cpp
|
| 2179 |
using ranlux24 = discard_block_engine<ranlux24_base, 223, 23>;
|
| 2180 |
```
|
| 2181 |
|
| 2182 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2183 |
+
default-constructed object of type `ranlux24` produces the value
|
| 2184 |
9901578.
|
| 2185 |
|
| 2186 |
``` cpp
|
| 2187 |
using ranlux48 = discard_block_engine<ranlux48_base, 389, 11>;
|
| 2188 |
```
|
| 2189 |
|
| 2190 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2191 |
+
default-constructed object of type `ranlux48` produces the value
|
| 2192 |
249142670248501.
|
| 2193 |
|
| 2194 |
``` cpp
|
| 2195 |
using knuth_b = shuffle_order_engine<minstd_rand0,256>;
|
| 2196 |
```
|
| 2197 |
|
| 2198 |
+
*Required behavior:* The 10000ᵗʰ consecutive invocation of a
|
| 2199 |
+
default-constructed object of type `knuth_b` produces the value
|
| 2200 |
1112339016.
|
| 2201 |
|
| 2202 |
``` cpp
|
| 2203 |
using default_random_engine = implementation-defined;
|
| 2204 |
```
|
|
|
|
| 2231 |
// generator characteristics
|
| 2232 |
static constexpr result_type min() { return numeric_limits<result_type>::min(); }
|
| 2233 |
static constexpr result_type max() { return numeric_limits<result_type>::max(); }
|
| 2234 |
|
| 2235 |
// constructors
|
| 2236 |
+
random_device() : random_device(implementation-defined) {}
|
| 2237 |
+
explicit random_device(const string& token);
|
| 2238 |
|
| 2239 |
// generating functions
|
| 2240 |
result_type operator()();
|
| 2241 |
|
| 2242 |
// property functions
|
|
|
|
| 2247 |
void operator=(const random_device&) = delete;
|
| 2248 |
};
|
| 2249 |
```
|
| 2250 |
|
| 2251 |
``` cpp
|
| 2252 |
+
explicit random_device(const string& token);
|
| 2253 |
```
|
| 2254 |
|
| 2255 |
+
*Remarks:* The semantics of the `token` parameter and the token value
|
| 2256 |
+
used by the default constructor are *implementation-defined*. [^3]
|
|
|
|
| 2257 |
|
| 2258 |
*Throws:* A value of an *implementation-defined* type derived from
|
| 2259 |
`exception` if the `random_device` could not be initialized.
|
| 2260 |
|
| 2261 |
``` cpp
|
|
|
|
| 2269 |
``` cpp
|
| 2270 |
result_type operator()();
|
| 2271 |
```
|
| 2272 |
|
| 2273 |
*Returns:* A nondeterministic random value, uniformly distributed
|
| 2274 |
+
between `min()` and `max()` (inclusive). It is *implementation-defined*
|
| 2275 |
how these values are generated.
|
| 2276 |
|
| 2277 |
*Throws:* A value of an *implementation-defined* type derived from
|
| 2278 |
`exception` if a random number could not be obtained.
|
| 2279 |
|
|
|
|
| 2314 |
|
| 2315 |
``` cpp
|
| 2316 |
seed_seq();
|
| 2317 |
```
|
| 2318 |
|
| 2319 |
+
*Ensures:* `v.empty()` is `true`.
|
|
|
|
| 2320 |
|
| 2321 |
*Throws:* Nothing.
|
| 2322 |
|
| 2323 |
``` cpp
|
| 2324 |
template<class T>
|
| 2325 |
seed_seq(initializer_list<T> il);
|
| 2326 |
```
|
| 2327 |
|
| 2328 |
+
*Mandates:* `T` is an integer type.
|
| 2329 |
|
| 2330 |
*Effects:* Same as `seed_seq(il.begin(), il.end())`.
|
| 2331 |
|
| 2332 |
``` cpp
|
| 2333 |
template<class InputIterator>
|
| 2334 |
seed_seq(InputIterator begin, InputIterator end);
|
| 2335 |
```
|
| 2336 |
|
| 2337 |
+
*Mandates:* `iterator_traits<InputIterator>::value_type` is an integer
|
|
|
|
|
|
|
| 2338 |
type.
|
| 2339 |
|
| 2340 |
+
*Preconditions:* `InputIterator` meets the *Cpp17InputIterator*
|
| 2341 |
+
requirements [[input.iterators]].
|
| 2342 |
+
|
| 2343 |
+
*Effects:* Initializes `v` by the following algorithm:
|
| 2344 |
|
| 2345 |
``` cpp
|
| 2346 |
for (InputIterator s = begin; s != end; ++s)
|
| 2347 |
v.push_back((*s) mod 2³²);
|
| 2348 |
```
|
|
|
|
| 2350 |
``` cpp
|
| 2351 |
template<class RandomAccessIterator>
|
| 2352 |
void generate(RandomAccessIterator begin, RandomAccessIterator end);
|
| 2353 |
```
|
| 2354 |
|
| 2355 |
+
*Mandates:* `iterator_traits<RandomAccessIterator>::value_type` is an
|
|
|
|
|
|
|
| 2356 |
unsigned integer type capable of accommodating 32-bit quantities.
|
| 2357 |
|
| 2358 |
+
*Preconditions:* `RandomAccessIterator` meets the
|
| 2359 |
+
*Cpp17RandomAccessIterator* requirements [[random.access.iterators]] and
|
| 2360 |
+
the requirements of a mutable iterator.
|
| 2361 |
+
|
| 2362 |
*Effects:* Does nothing if `begin == end`. Otherwise, with
|
| 2363 |
s = `v.size()` and n = `end` - `begin`, fills the supplied range
|
| 2364 |
[`begin`,`end`) according to the following algorithm in which each
|
| 2365 |
operation is to be carried out modulo 2³², each indexing operator
|
| 2366 |
applied to `begin` is to be taken modulo n, and T(x) is defined as
|
| 2367 |
+
$x \xor (x \rightshift 27)$:
|
| 2368 |
+
|
| 2369 |
+
- By way of initialization, set each element of the range to the value
|
| 2370 |
+
`0x8b8b8b8b`. Additionally, for use in subsequent steps, let
|
| 2371 |
+
p = (n - t) / 2 and let q = p + t, where $$%
|
| 2372 |
+
t = (n \ge 623) \mbox{ ? } 11 \mbox{ : } (n \ge 68) \mbox{ ? } 7 \mbox{ : } (n \ge 39) \mbox{ ? } 5 \mbox{ : } (n \ge 7) \mbox{ ? } 3 \mbox{ : } (n - 1)/2;$$
|
| 2373 |
+
- With m as the larger of s + 1 and n, transform the elements of the
|
| 2374 |
+
range: iteratively for k = 0, …, m - 1, calculate values
|
| 2375 |
+
$$\begin{aligned}
|
| 2376 |
+
r_1 & = &
|
| 2377 |
+
1664525 \cdot T( \texttt{begin[}k\texttt{]}
|
| 2378 |
+
\xor \texttt{begin[}k+p\texttt{]}
|
| 2379 |
+
\xor \texttt{begin[}k-1 \texttt{]}
|
| 2380 |
+
)
|
| 2381 |
+
\\
|
| 2382 |
+
r_2 & = & r_1 + \left\{
|
| 2383 |
+
\begin{array}{cl}
|
| 2384 |
+
s & \mbox{, } k = 0
|
| 2385 |
+
\\
|
| 2386 |
+
k \bmod n + \texttt{v[}k-1\texttt{]} & \mbox{, } 0 < k \le s
|
| 2387 |
+
\\
|
| 2388 |
+
k \bmod n & \mbox{, } s < k
|
| 2389 |
+
\end{array}
|
| 2390 |
+
\right.
|
| 2391 |
+
|
| 2392 |
+
\end{aligned}$$ and, in order, increment `begin[`k+p`]` by r₁,
|
| 2393 |
+
increment `begin[`k+q`]` by r₂, and set `begin[`k`]` to r₂.
|
| 2394 |
+
- Transform the elements of the range again, beginning where the
|
| 2395 |
+
previous step ended: iteratively for k = m, …, m + n - 1, calculate
|
| 2396 |
+
values $$\begin{aligned}
|
| 2397 |
+
r_3 & = &
|
| 2398 |
+
1566083941 \cdot T( \texttt{begin[}k \texttt{]}
|
| 2399 |
+
+ \texttt{begin[}k+p\texttt{]}
|
| 2400 |
+
+ \texttt{begin[}k-1\texttt{]}
|
| 2401 |
+
)
|
| 2402 |
+
\\
|
| 2403 |
+
r_4 & = & r_3 - (k \bmod n)
|
| 2404 |
+
|
| 2405 |
+
\end{aligned}$$ and, in order, update `begin[`k+p`]` by xoring it with
|
| 2406 |
+
r₃, update `begin[`k+q`]` by xoring it with r₄, and set `begin[`k`]`
|
| 2407 |
+
to r₄.
|
| 2408 |
|
| 2409 |
*Throws:* What and when `RandomAccessIterator` operations of `begin` and
|
| 2410 |
`end` throw.
|
| 2411 |
|
| 2412 |
``` cpp
|
|
|
|
| 2421 |
``` cpp
|
| 2422 |
template<class OutputIterator>
|
| 2423 |
void param(OutputIterator dest) const;
|
| 2424 |
```
|
| 2425 |
|
| 2426 |
+
*Mandates:* Values of type `result_type` are
|
| 2427 |
+
writable [[iterator.requirements.general]] to `dest`.
|
| 2428 |
+
|
| 2429 |
+
*Preconditions:* `OutputIterator` meets the *Cpp17OutputIterator*
|
| 2430 |
+
requirements [[output.iterators]].
|
| 2431 |
|
| 2432 |
*Effects:* Copies the sequence of prepared 32-bit units to the given
|
| 2433 |
destination, as if by executing the following statement:
|
| 2434 |
|
| 2435 |
``` cpp
|
|
|
|
| 2438 |
|
| 2439 |
*Throws:* What and when `OutputIterator` operations of `dest` throw.
|
| 2440 |
|
| 2441 |
#### Function template `generate_canonical` <a id="rand.util.canonical">[[rand.util.canonical]]</a>
|
| 2442 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 2443 |
``` cpp
|
| 2444 |
template<class RealType, size_t bits, class URBG>
|
| 2445 |
RealType generate_canonical(URBG& g);
|
| 2446 |
```
|
| 2447 |
|
|
|
|
| 2454 |
$$S = \sum_{i=0}^{k-1} (g_i - \texttt{g.min()})
|
| 2455 |
\cdot R^i$$ using arithmetic of type `RealType`.
|
| 2456 |
|
| 2457 |
*Returns:* S / Rᵏ.
|
| 2458 |
|
| 2459 |
+
[*Note 1*: 0 ≤ S / Rᵏ < 1. — *end note*]
|
| 2460 |
+
|
| 2461 |
*Throws:* What and when `g` throws.
|
| 2462 |
|
| 2463 |
+
[*Note 2*: If the values gᵢ produced by `g` are uniformly distributed,
|
| 2464 |
+
the instantiation’s results are distributed as uniformly as possible.
|
| 2465 |
+
Obtaining a value in this way can be a useful step in the process of
|
| 2466 |
+
transforming a value generated by a uniform random bit generator into a
|
| 2467 |
+
value that can be delivered by a random number
|
| 2468 |
+
distribution. — *end note*]
|
| 2469 |
+
|
| 2470 |
### Random number distribution class templates <a id="rand.dist">[[rand.dist]]</a>
|
| 2471 |
|
| 2472 |
#### In general <a id="rand.dist.general">[[rand.dist.general]]</a>
|
| 2473 |
|
| 2474 |
+
Each type instantiated from a class template specified in this
|
| 2475 |
+
subclause [[rand.dist]] meets the requirements of a random number
|
| 2476 |
+
distribution [[rand.req.dist]] type.
|
| 2477 |
|
| 2478 |
+
Descriptions are provided in this subclause [[rand.dist]] only for
|
| 2479 |
distribution operations that are not described in [[rand.req.dist]] or
|
| 2480 |
for operations where there is additional semantic information. In
|
| 2481 |
particular, declarations for copy constructors, for copy assignment
|
| 2482 |
operators, for streaming operators, and for equality and inequality
|
| 2483 |
operators are not shown in the synopses.
|
| 2484 |
|
| 2485 |
The algorithms for producing each of the specified distributions are
|
| 2486 |
*implementation-defined*.
|
| 2487 |
|
| 2488 |
The value of each probability density function p(z) and of each discrete
|
| 2489 |
+
probability function P(zᵢ) specified in this subclause is 0 everywhere
|
| 2490 |
outside its stated domain.
|
| 2491 |
|
| 2492 |
#### Uniform distributions <a id="rand.dist.uni">[[rand.dist.uni]]</a>
|
| 2493 |
|
| 2494 |
##### Class template `uniform_int_distribution` <a id="rand.dist.uni.int">[[rand.dist.uni.int]]</a>
|
| 2495 |
|
| 2496 |
A `uniform_int_distribution` random number distribution produces random
|
| 2497 |
integers i, a ≤ i ≤ b, distributed according to the constant discrete
|
| 2498 |
+
probability function $$P(i\,|\,a,b) = 1 / (b - a + 1) \text{ .}$$
|
|
|
|
|
|
|
| 2499 |
|
| 2500 |
``` cpp
|
| 2501 |
template<class IntType = int>
|
| 2502 |
class uniform_int_distribution {
|
| 2503 |
public:
|
| 2504 |
// types
|
| 2505 |
using result_type = IntType;
|
| 2506 |
using param_type = unspecified;
|
| 2507 |
|
| 2508 |
// constructors and reset functions
|
| 2509 |
+
uniform_int_distribution() : uniform_int_distribution(0) {}
|
| 2510 |
+
explicit uniform_int_distribution(IntType a, IntType b = numeric_limits<IntType>::max());
|
| 2511 |
explicit uniform_int_distribution(const param_type& parm);
|
| 2512 |
void reset();
|
| 2513 |
|
| 2514 |
// generating functions
|
| 2515 |
template<class URBG>
|
|
|
|
| 2526 |
result_type max() const;
|
| 2527 |
};
|
| 2528 |
```
|
| 2529 |
|
| 2530 |
``` cpp
|
| 2531 |
+
explicit uniform_int_distribution(IntType a, IntType b = numeric_limits<IntType>::max());
|
| 2532 |
```
|
| 2533 |
|
| 2534 |
+
*Preconditions:* `a` ≤ `b`.
|
| 2535 |
|
| 2536 |
+
*Remarks:* `a` and `b` correspond to the respective parameters of the
|
| 2537 |
+
distribution.
|
| 2538 |
|
| 2539 |
``` cpp
|
| 2540 |
result_type a() const;
|
| 2541 |
```
|
| 2542 |
|
|
|
|
| 2552 |
|
| 2553 |
##### Class template `uniform_real_distribution` <a id="rand.dist.uni.real">[[rand.dist.uni.real]]</a>
|
| 2554 |
|
| 2555 |
A `uniform_real_distribution` random number distribution produces random
|
| 2556 |
numbers x, a ≤ x < b, distributed according to the constant probability
|
| 2557 |
+
density function $$p(x\,|\,a,b) = 1 / (b - a) \text{ .}$$
|
|
|
|
|
|
|
| 2558 |
|
| 2559 |
[*Note 1*: This implies that p(x | a,b) is undefined when
|
| 2560 |
`a == b`. — *end note*]
|
| 2561 |
|
| 2562 |
``` cpp
|
|
|
|
| 2566 |
// types
|
| 2567 |
using result_type = RealType;
|
| 2568 |
using param_type = unspecified;
|
| 2569 |
|
| 2570 |
// constructors and reset functions
|
| 2571 |
+
uniform_real_distribution() : uniform_real_distribution(0.0) {}
|
| 2572 |
+
explicit uniform_real_distribution(RealType a, RealType b = 1.0);
|
| 2573 |
explicit uniform_real_distribution(const param_type& parm);
|
| 2574 |
void reset();
|
| 2575 |
|
| 2576 |
// generating functions
|
| 2577 |
template<class URBG>
|
|
|
|
| 2588 |
result_type max() const;
|
| 2589 |
};
|
| 2590 |
```
|
| 2591 |
|
| 2592 |
``` cpp
|
| 2593 |
+
explicit uniform_real_distribution(RealType a, RealType b = 1.0);
|
| 2594 |
```
|
| 2595 |
|
| 2596 |
+
*Preconditions:* `a` ≤ `b` and
|
| 2597 |
+
`b` - `a` ≤ `numeric_limits<RealType>::max()`.
|
| 2598 |
|
| 2599 |
+
*Remarks:* `a` and `b` correspond to the respective parameters of the
|
| 2600 |
+
distribution.
|
| 2601 |
|
| 2602 |
``` cpp
|
| 2603 |
result_type a() const;
|
| 2604 |
```
|
| 2605 |
|
|
|
|
| 2616 |
#### Bernoulli distributions <a id="rand.dist.bern">[[rand.dist.bern]]</a>
|
| 2617 |
|
| 2618 |
##### Class `bernoulli_distribution` <a id="rand.dist.bern.bernoulli">[[rand.dist.bern.bernoulli]]</a>
|
| 2619 |
|
| 2620 |
A `bernoulli_distribution` random number distribution produces `bool`
|
| 2621 |
+
values b distributed according to the discrete probability function
|
| 2622 |
+
$$P(b\,|\,p) = \left\{ \begin{array}{ll}
|
| 2623 |
+
p & \text{ if $b = \tcode{true}$, or} \\
|
| 2624 |
+
1 - p & \text{ if $b = \tcode{false}$.}
|
| 2625 |
+
\end{array}\right.$$
|
|
|
|
|
|
|
| 2626 |
|
| 2627 |
``` cpp
|
| 2628 |
class bernoulli_distribution {
|
| 2629 |
public:
|
| 2630 |
// types
|
| 2631 |
using result_type = bool;
|
| 2632 |
using param_type = unspecified;
|
| 2633 |
|
| 2634 |
// constructors and reset functions
|
| 2635 |
+
bernoulli_distribution() : bernoulli_distribution(0.5) {}
|
| 2636 |
+
explicit bernoulli_distribution(double p);
|
| 2637 |
explicit bernoulli_distribution(const param_type& parm);
|
| 2638 |
void reset();
|
| 2639 |
|
| 2640 |
// generating functions
|
| 2641 |
template<class URBG>
|
|
|
|
| 2651 |
result_type max() const;
|
| 2652 |
};
|
| 2653 |
```
|
| 2654 |
|
| 2655 |
``` cpp
|
| 2656 |
+
explicit bernoulli_distribution(double p);
|
| 2657 |
```
|
| 2658 |
|
| 2659 |
+
*Preconditions:* 0 ≤ `p` ≤ 1.
|
| 2660 |
|
| 2661 |
+
*Remarks:* `p` corresponds to the parameter of the distribution.
|
|
|
|
| 2662 |
|
| 2663 |
``` cpp
|
| 2664 |
double p() const;
|
| 2665 |
```
|
| 2666 |
|
|
|
|
| 2669 |
|
| 2670 |
##### Class template `binomial_distribution` <a id="rand.dist.bern.bin">[[rand.dist.bern.bin]]</a>
|
| 2671 |
|
| 2672 |
A `binomial_distribution` random number distribution produces integer
|
| 2673 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2674 |
+
$$P(i\,|\,t,p) = \binom{t}{i} \cdot p^i \cdot (1-p)^{t-i} \text{ .}$$
|
|
|
|
|
|
|
|
|
|
| 2675 |
|
| 2676 |
``` cpp
|
| 2677 |
template<class IntType = int>
|
| 2678 |
class binomial_distribution {
|
| 2679 |
public:
|
| 2680 |
// types
|
| 2681 |
using result_type = IntType;
|
| 2682 |
using param_type = unspecified;
|
| 2683 |
|
| 2684 |
// constructors and reset functions
|
| 2685 |
+
binomial_distribution() : binomial_distribution(1) {}
|
| 2686 |
+
explicit binomial_distribution(IntType t, double p = 0.5);
|
| 2687 |
explicit binomial_distribution(const param_type& parm);
|
| 2688 |
void reset();
|
| 2689 |
|
| 2690 |
// generating functions
|
| 2691 |
template<class URBG>
|
|
|
|
| 2702 |
result_type max() const;
|
| 2703 |
};
|
| 2704 |
```
|
| 2705 |
|
| 2706 |
``` cpp
|
| 2707 |
+
explicit binomial_distribution(IntType t, double p = 0.5);
|
| 2708 |
```
|
| 2709 |
|
| 2710 |
+
*Preconditions:* 0 ≤ `p` ≤ 1 and 0 ≤ `t`.
|
| 2711 |
|
| 2712 |
+
*Remarks:* `t` and `p` correspond to the respective parameters of the
|
| 2713 |
+
distribution.
|
| 2714 |
|
| 2715 |
``` cpp
|
| 2716 |
IntType t() const;
|
| 2717 |
```
|
| 2718 |
|
|
|
|
| 2728 |
|
| 2729 |
##### Class template `geometric_distribution` <a id="rand.dist.bern.geo">[[rand.dist.bern.geo]]</a>
|
| 2730 |
|
| 2731 |
A `geometric_distribution` random number distribution produces integer
|
| 2732 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2733 |
+
$$P(i\,|\,p) = p \cdot (1-p)^{i} \text{ .}$$
|
|
|
|
|
|
|
|
|
|
| 2734 |
|
| 2735 |
``` cpp
|
| 2736 |
template<class IntType = int>
|
| 2737 |
class geometric_distribution {
|
| 2738 |
public:
|
| 2739 |
// types
|
| 2740 |
using result_type = IntType;
|
| 2741 |
using param_type = unspecified;
|
| 2742 |
|
| 2743 |
// constructors and reset functions
|
| 2744 |
+
geometric_distribution() : geometric_distribution(0.5) {}
|
| 2745 |
+
explicit geometric_distribution(double p);
|
| 2746 |
explicit geometric_distribution(const param_type& parm);
|
| 2747 |
void reset();
|
| 2748 |
|
| 2749 |
// generating functions
|
| 2750 |
template<class URBG>
|
|
|
|
| 2760 |
result_type max() const;
|
| 2761 |
};
|
| 2762 |
```
|
| 2763 |
|
| 2764 |
``` cpp
|
| 2765 |
+
explicit geometric_distribution(double p);
|
| 2766 |
```
|
| 2767 |
|
| 2768 |
+
*Preconditions:* 0 < `p` < 1.
|
| 2769 |
|
| 2770 |
+
*Remarks:* `p` corresponds to the parameter of the distribution.
|
|
|
|
| 2771 |
|
| 2772 |
``` cpp
|
| 2773 |
double p() const;
|
| 2774 |
```
|
| 2775 |
|
|
|
|
| 2778 |
|
| 2779 |
##### Class template `negative_binomial_distribution` <a id="rand.dist.bern.negbin">[[rand.dist.bern.negbin]]</a>
|
| 2780 |
|
| 2781 |
A `negative_binomial_distribution` random number distribution produces
|
| 2782 |
random integers i ≥ 0 distributed according to the discrete probability
|
| 2783 |
+
function
|
| 2784 |
+
$$P(i\,|\,k,p) = \binom{k+i-1}{i} \cdot p^k \cdot (1-p)^i \text{ .}$$
|
|
|
|
|
|
|
| 2785 |
|
| 2786 |
[*Note 1*: This implies that P(i | k,p) is undefined when
|
| 2787 |
`p == 1`. — *end note*]
|
| 2788 |
|
| 2789 |
``` cpp
|
|
|
|
| 2793 |
// types
|
| 2794 |
using result_type = IntType;
|
| 2795 |
using param_type = unspecified;
|
| 2796 |
|
| 2797 |
// constructor and reset functions
|
| 2798 |
+
negative_binomial_distribution() : negative_binomial_distribution(1) {}
|
| 2799 |
+
explicit negative_binomial_distribution(IntType k, double p = 0.5);
|
| 2800 |
explicit negative_binomial_distribution(const param_type& parm);
|
| 2801 |
void reset();
|
| 2802 |
|
| 2803 |
// generating functions
|
| 2804 |
template<class URBG>
|
|
|
|
| 2815 |
result_type max() const;
|
| 2816 |
};
|
| 2817 |
```
|
| 2818 |
|
| 2819 |
``` cpp
|
| 2820 |
+
explicit negative_binomial_distribution(IntType k, double p = 0.5);
|
| 2821 |
```
|
| 2822 |
|
| 2823 |
+
*Preconditions:* 0 < `p` ≤ 1 and 0 < `k`.
|
| 2824 |
|
| 2825 |
+
*Remarks:* `k` and `p` correspond to the respective parameters of the
|
| 2826 |
+
distribution.
|
| 2827 |
|
| 2828 |
``` cpp
|
| 2829 |
IntType k() const;
|
| 2830 |
```
|
| 2831 |
|
|
|
|
| 2843 |
|
| 2844 |
##### Class template `poisson_distribution` <a id="rand.dist.pois.poisson">[[rand.dist.pois.poisson]]</a>
|
| 2845 |
|
| 2846 |
A `poisson_distribution` random number distribution produces integer
|
| 2847 |
values i ≥ 0 distributed according to the discrete probability function
|
| 2848 |
+
$$P(i\,|\,\mu) = \frac{e^{-\mu} \mu^{i}}{i\,!} \text{ .}$$ The
|
| 2849 |
+
distribution parameter μ is also known as this distribution’s *mean* .
|
|
|
|
|
|
|
|
|
|
|
|
|
| 2850 |
|
| 2851 |
``` cpp
|
| 2852 |
template<class IntType = int>
|
| 2853 |
class poisson_distribution
|
| 2854 |
{
|
|
|
|
| 2856 |
// types
|
| 2857 |
using result_type = IntType;
|
| 2858 |
using param_type = unspecified;
|
| 2859 |
|
| 2860 |
// constructors and reset functions
|
| 2861 |
+
poisson_distribution() : poisson_distribution(1.0) {}
|
| 2862 |
+
explicit poisson_distribution(double mean);
|
| 2863 |
explicit poisson_distribution(const param_type& parm);
|
| 2864 |
void reset();
|
| 2865 |
|
| 2866 |
// generating functions
|
| 2867 |
template<class URBG>
|
|
|
|
| 2877 |
result_type max() const;
|
| 2878 |
};
|
| 2879 |
```
|
| 2880 |
|
| 2881 |
``` cpp
|
| 2882 |
+
explicit poisson_distribution(double mean);
|
| 2883 |
```
|
| 2884 |
|
| 2885 |
+
*Preconditions:* 0 < `mean`.
|
| 2886 |
|
| 2887 |
+
*Remarks:* `mean` corresponds to the parameter of the distribution.
|
|
|
|
| 2888 |
|
| 2889 |
``` cpp
|
| 2890 |
double mean() const;
|
| 2891 |
```
|
| 2892 |
|
|
|
|
| 2895 |
|
| 2896 |
##### Class template `exponential_distribution` <a id="rand.dist.pois.exp">[[rand.dist.pois.exp]]</a>
|
| 2897 |
|
| 2898 |
An `exponential_distribution` random number distribution produces random
|
| 2899 |
numbers x > 0 distributed according to the probability density function
|
| 2900 |
+
$$p(x\,|\,\lambda) = \lambda e^{-\lambda x} \text{ .}$$
|
|
|
|
|
|
|
|
|
|
| 2901 |
|
| 2902 |
``` cpp
|
| 2903 |
template<class RealType = double>
|
| 2904 |
class exponential_distribution {
|
| 2905 |
public:
|
| 2906 |
// types
|
| 2907 |
using result_type = RealType;
|
| 2908 |
using param_type = unspecified;
|
| 2909 |
|
| 2910 |
// constructors and reset functions
|
| 2911 |
+
exponential_distribution() : exponential_distribution(1.0) {}
|
| 2912 |
+
explicit exponential_distribution(RealType lambda);
|
| 2913 |
explicit exponential_distribution(const param_type& parm);
|
| 2914 |
void reset();
|
| 2915 |
|
| 2916 |
// generating functions
|
| 2917 |
template<class URBG>
|
|
|
|
| 2927 |
result_type max() const;
|
| 2928 |
};
|
| 2929 |
```
|
| 2930 |
|
| 2931 |
``` cpp
|
| 2932 |
+
explicit exponential_distribution(RealType lambda);
|
| 2933 |
```
|
| 2934 |
|
| 2935 |
+
*Preconditions:* 0 < `lambda`.
|
| 2936 |
|
| 2937 |
+
*Remarks:* `lambda` corresponds to the parameter of the distribution.
|
|
|
|
| 2938 |
|
| 2939 |
``` cpp
|
| 2940 |
RealType lambda() const;
|
| 2941 |
```
|
| 2942 |
|
|
|
|
| 2945 |
|
| 2946 |
##### Class template `gamma_distribution` <a id="rand.dist.pois.gamma">[[rand.dist.pois.gamma]]</a>
|
| 2947 |
|
| 2948 |
A `gamma_distribution` random number distribution produces random
|
| 2949 |
numbers x > 0 distributed according to the probability density function
|
| 2950 |
+
$$p(x\,|\,\alpha,\beta) =
|
| 2951 |
+
\frac{e^{-x/\beta}}{\beta^{\alpha} \cdot \Gamma(\alpha)} \, \cdot \, x^{\, \alpha-1}
|
| 2952 |
+
\text{ .}$$
|
|
|
|
|
|
|
| 2953 |
|
| 2954 |
``` cpp
|
| 2955 |
template<class RealType = double>
|
| 2956 |
class gamma_distribution {
|
| 2957 |
public:
|
| 2958 |
// types
|
| 2959 |
using result_type = RealType;
|
| 2960 |
using param_type = unspecified;
|
| 2961 |
|
| 2962 |
// constructors and reset functions
|
| 2963 |
+
gamma_distribution() : gamma_distribution(1.0) {}
|
| 2964 |
+
explicit gamma_distribution(RealType alpha, RealType beta = 1.0);
|
| 2965 |
explicit gamma_distribution(const param_type& parm);
|
| 2966 |
void reset();
|
| 2967 |
|
| 2968 |
// generating functions
|
| 2969 |
template<class URBG>
|
|
|
|
| 2980 |
result_type max() const;
|
| 2981 |
};
|
| 2982 |
```
|
| 2983 |
|
| 2984 |
``` cpp
|
| 2985 |
+
explicit gamma_distribution(RealType alpha, RealType beta = 1.0);
|
| 2986 |
```
|
| 2987 |
|
| 2988 |
+
*Preconditions:* 0 < `alpha` and 0 < `beta`.
|
| 2989 |
|
| 2990 |
+
*Remarks:* `alpha` and `beta` correspond to the parameters of the
|
| 2991 |
+
distribution.
|
| 2992 |
|
| 2993 |
``` cpp
|
| 2994 |
RealType alpha() const;
|
| 2995 |
```
|
| 2996 |
|
|
|
|
| 3006 |
|
| 3007 |
##### Class template `weibull_distribution` <a id="rand.dist.pois.weibull">[[rand.dist.pois.weibull]]</a>
|
| 3008 |
|
| 3009 |
A `weibull_distribution` random number distribution produces random
|
| 3010 |
numbers x ≥ 0 distributed according to the probability density function
|
| 3011 |
+
$$p(x\,|\,a,b) = \frac{a}{b}
|
|
|
|
|
|
|
| 3012 |
\cdot \left(\frac{x}{b}\right)^{a-1}
|
| 3013 |
\cdot \, \exp\left( -\left(\frac{x}{b}\right)^a\right)
|
| 3014 |
+
\text{ .}$$
|
| 3015 |
|
| 3016 |
``` cpp
|
| 3017 |
template<class RealType = double>
|
| 3018 |
class weibull_distribution {
|
| 3019 |
public:
|
| 3020 |
// types
|
| 3021 |
using result_type = RealType;
|
| 3022 |
using param_type = unspecified;
|
| 3023 |
|
| 3024 |
// constructor and reset functions
|
| 3025 |
+
weibull_distribution() : weibull_distribution(1.0) {}
|
| 3026 |
+
explicit weibull_distribution(RealType a, RealType b = 1.0);
|
| 3027 |
explicit weibull_distribution(const param_type& parm);
|
| 3028 |
void reset();
|
| 3029 |
|
| 3030 |
// generating functions
|
| 3031 |
template<class URBG>
|
|
|
|
| 3042 |
result_type max() const;
|
| 3043 |
};
|
| 3044 |
```
|
| 3045 |
|
| 3046 |
``` cpp
|
| 3047 |
+
explicit weibull_distribution(RealType a, RealType b = 1.0);
|
| 3048 |
```
|
| 3049 |
|
| 3050 |
+
*Preconditions:* 0 < `a` and 0 < `b`.
|
| 3051 |
|
| 3052 |
+
*Remarks:* `a` and `b` correspond to the respective parameters of the
|
| 3053 |
+
distribution.
|
| 3054 |
|
| 3055 |
``` cpp
|
| 3056 |
RealType a() const;
|
| 3057 |
```
|
| 3058 |
|
|
|
|
| 3068 |
|
| 3069 |
##### Class template `extreme_value_distribution` <a id="rand.dist.pois.extreme">[[rand.dist.pois.extreme]]</a>
|
| 3070 |
|
| 3071 |
An `extreme_value_distribution` random number distribution produces
|
| 3072 |
random numbers x distributed according to the probability density
|
| 3073 |
+
function[^6] $$p(x\,|\,a,b) = \frac{1}{b}
|
| 3074 |
+
\cdot \exp\left(\frac{a-x}{b} - \exp\left(\frac{a-x}{b}\right)\right)
|
| 3075 |
+
\text{ .}$$
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3076 |
|
| 3077 |
``` cpp
|
| 3078 |
template<class RealType = double>
|
| 3079 |
class extreme_value_distribution {
|
| 3080 |
public:
|
| 3081 |
// types
|
| 3082 |
using result_type = RealType;
|
| 3083 |
using param_type = unspecified;
|
| 3084 |
|
| 3085 |
// constructor and reset functions
|
| 3086 |
+
extreme_value_distribution() : extreme_value_distribution(0.0) {}
|
| 3087 |
+
explicit extreme_value_distribution(RealType a, RealType b = 1.0);
|
| 3088 |
explicit extreme_value_distribution(const param_type& parm);
|
| 3089 |
void reset();
|
| 3090 |
|
| 3091 |
// generating functions
|
| 3092 |
template<class URBG>
|
|
|
|
| 3103 |
result_type max() const;
|
| 3104 |
};
|
| 3105 |
```
|
| 3106 |
|
| 3107 |
``` cpp
|
| 3108 |
+
explicit extreme_value_distribution(RealType a, RealType b = 1.0);
|
| 3109 |
```
|
| 3110 |
|
| 3111 |
+
*Preconditions:* 0 < `b`.
|
| 3112 |
|
| 3113 |
+
*Remarks:* `a` and `b` correspond to the respective parameters of the
|
| 3114 |
+
distribution.
|
| 3115 |
|
| 3116 |
``` cpp
|
| 3117 |
RealType a() const;
|
| 3118 |
```
|
| 3119 |
|
|
|
|
| 3139 |
% e^{-(x-\mu)^2 / (2\sigma^2)}
|
| 3140 |
\exp{\left(- \, \frac{(x - \mu)^2}
|
| 3141 |
{2 \sigma^2}
|
| 3142 |
\right)
|
| 3143 |
}
|
| 3144 |
+
\text{ .}$$ The distribution parameters μ and σ are also known as this
|
| 3145 |
distribution’s *mean* and *standard deviation* .
|
| 3146 |
|
| 3147 |
``` cpp
|
| 3148 |
template<class RealType = double>
|
| 3149 |
class normal_distribution {
|
|
|
|
| 3151 |
// types
|
| 3152 |
using result_type = RealType;
|
| 3153 |
using param_type = unspecified;
|
| 3154 |
|
| 3155 |
// constructors and reset functions
|
| 3156 |
+
normal_distribution() : normal_distribution(0.0) {}
|
| 3157 |
+
explicit normal_distribution(RealType mean, RealType stddev = 1.0);
|
| 3158 |
explicit normal_distribution(const param_type& parm);
|
| 3159 |
void reset();
|
| 3160 |
|
| 3161 |
// generating functions
|
| 3162 |
template<class URBG>
|
|
|
|
| 3173 |
result_type max() const;
|
| 3174 |
};
|
| 3175 |
```
|
| 3176 |
|
| 3177 |
``` cpp
|
| 3178 |
+
explicit normal_distribution(RealType mean, RealType stddev = 1.0);
|
| 3179 |
```
|
| 3180 |
|
| 3181 |
+
*Preconditions:* 0 < `stddev`.
|
| 3182 |
|
| 3183 |
+
*Remarks:* `mean` and `stddev` correspond to the respective parameters
|
| 3184 |
+
of the distribution.
|
| 3185 |
|
| 3186 |
``` cpp
|
| 3187 |
RealType mean() const;
|
| 3188 |
```
|
| 3189 |
|
|
|
|
| 3199 |
|
| 3200 |
##### Class template `lognormal_distribution` <a id="rand.dist.norm.lognormal">[[rand.dist.norm.lognormal]]</a>
|
| 3201 |
|
| 3202 |
A `lognormal_distribution` random number distribution produces random
|
| 3203 |
numbers x > 0 distributed according to the probability density function
|
| 3204 |
+
$$p(x\,|\,m,s) = \frac{1}{s x \sqrt{2 \pi}}
|
| 3205 |
+
\cdot \exp{\left(-\frac{(\ln{x} - m)^2}{2 s^2}\right)}
|
| 3206 |
+
\text{ .}$$
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3207 |
|
| 3208 |
``` cpp
|
| 3209 |
template<class RealType = double>
|
| 3210 |
class lognormal_distribution {
|
| 3211 |
public:
|
| 3212 |
// types
|
| 3213 |
using result_type = RealType;
|
| 3214 |
using param_type = unspecified;
|
| 3215 |
|
| 3216 |
// constructor and reset functions
|
| 3217 |
+
lognormal_distribution() : lognormal_distribution(0.0) {}
|
| 3218 |
+
explicit lognormal_distribution(RealType m, RealType s = 1.0);
|
| 3219 |
explicit lognormal_distribution(const param_type& parm);
|
| 3220 |
void reset();
|
| 3221 |
|
| 3222 |
// generating functions
|
| 3223 |
template<class URBG>
|
|
|
|
| 3234 |
result_type max() const;
|
| 3235 |
};
|
| 3236 |
```
|
| 3237 |
|
| 3238 |
``` cpp
|
| 3239 |
+
explicit lognormal_distribution(RealType m, RealType s = 1.0);
|
| 3240 |
```
|
| 3241 |
|
| 3242 |
+
*Preconditions:* 0 < `s`.
|
| 3243 |
|
| 3244 |
+
*Remarks:* `m` and `s` correspond to the respective parameters of the
|
| 3245 |
+
distribution.
|
| 3246 |
|
| 3247 |
``` cpp
|
| 3248 |
RealType m() const;
|
| 3249 |
```
|
| 3250 |
|
|
|
|
| 3260 |
|
| 3261 |
##### Class template `chi_squared_distribution` <a id="rand.dist.norm.chisq">[[rand.dist.norm.chisq]]</a>
|
| 3262 |
|
| 3263 |
A `chi_squared_distribution` random number distribution produces random
|
| 3264 |
numbers x > 0 distributed according to the probability density function
|
| 3265 |
+
$$p(x\,|\,n) = \frac{x^{(n/2)-1} \cdot e^{-x/2}}{\Gamma(n/2) \cdot 2^{n/2}} \text{ .}$$
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3266 |
|
| 3267 |
``` cpp
|
| 3268 |
template<class RealType = double>
|
| 3269 |
class chi_squared_distribution {
|
| 3270 |
public:
|
| 3271 |
// types
|
| 3272 |
using result_type = RealType;
|
| 3273 |
using param_type = unspecified;
|
| 3274 |
|
| 3275 |
// constructor and reset functions
|
| 3276 |
+
chi_squared_distribution() : chi_squared_distribution(1.0) {}
|
| 3277 |
+
explicit chi_squared_distribution(RealType n);
|
| 3278 |
explicit chi_squared_distribution(const param_type& parm);
|
| 3279 |
void reset();
|
| 3280 |
|
| 3281 |
// generating functions
|
| 3282 |
template<class URBG>
|
|
|
|
| 3292 |
result_type max() const;
|
| 3293 |
};
|
| 3294 |
```
|
| 3295 |
|
| 3296 |
``` cpp
|
| 3297 |
+
explicit chi_squared_distribution(RealType n);
|
| 3298 |
```
|
| 3299 |
|
| 3300 |
+
*Preconditions:* 0 < `n`.
|
| 3301 |
|
| 3302 |
+
*Remarks:* `n` corresponds to the parameter of the distribution.
|
|
|
|
| 3303 |
|
| 3304 |
``` cpp
|
| 3305 |
RealType n() const;
|
| 3306 |
```
|
| 3307 |
|
|
|
|
| 3309 |
constructed.
|
| 3310 |
|
| 3311 |
##### Class template `cauchy_distribution` <a id="rand.dist.norm.cauchy">[[rand.dist.norm.cauchy]]</a>
|
| 3312 |
|
| 3313 |
A `cauchy_distribution` random number distribution produces random
|
| 3314 |
+
numbers x distributed according to the probability density function
|
| 3315 |
+
$$p(x\,|\,a,b) = \left(\pi b \left(1 + \left(\frac{x-a}{b} \right)^2 \, \right)\right)^{-1} \text{ .}$$
|
|
|
|
|
|
|
| 3316 |
|
| 3317 |
``` cpp
|
| 3318 |
template<class RealType = double>
|
| 3319 |
class cauchy_distribution {
|
| 3320 |
public:
|
| 3321 |
// types
|
| 3322 |
using result_type = RealType;
|
| 3323 |
using param_type = unspecified;
|
| 3324 |
|
| 3325 |
// constructor and reset functions
|
| 3326 |
+
cauchy_distribution() : cauchy_distribution(0.0) {}
|
| 3327 |
+
explicit cauchy_distribution(RealType a, RealType b = 1.0);
|
| 3328 |
explicit cauchy_distribution(const param_type& parm);
|
| 3329 |
void reset();
|
| 3330 |
|
| 3331 |
// generating functions
|
| 3332 |
template<class URBG>
|
|
|
|
| 3343 |
result_type max() const;
|
| 3344 |
};
|
| 3345 |
```
|
| 3346 |
|
| 3347 |
``` cpp
|
| 3348 |
+
explicit cauchy_distribution(RealType a, RealType b = 1.0);
|
| 3349 |
```
|
| 3350 |
|
| 3351 |
+
*Preconditions:* 0 < `b`.
|
| 3352 |
|
| 3353 |
+
*Remarks:* `a` and `b` correspond to the respective parameters of the
|
| 3354 |
+
distribution.
|
| 3355 |
|
| 3356 |
``` cpp
|
| 3357 |
RealType a() const;
|
| 3358 |
```
|
| 3359 |
|
|
|
|
| 3369 |
|
| 3370 |
##### Class template `fisher_f_distribution` <a id="rand.dist.norm.f">[[rand.dist.norm.f]]</a>
|
| 3371 |
|
| 3372 |
A `fisher_f_distribution` random number distribution produces random
|
| 3373 |
numbers x ≥ 0 distributed according to the probability density function
|
| 3374 |
+
$$p(x\,|\,m,n) = \frac{\Gamma\big((m+n)/2\big)}{\Gamma(m/2) \; \Gamma(n/2)}
|
| 3375 |
+
\cdot \left(\frac{m}{n}\right)^{m/2}
|
| 3376 |
+
\cdot x^{(m/2)-1}
|
| 3377 |
+
\cdot \left(1 + \frac{m x}{n}\right)^{-(m + n)/2}
|
| 3378 |
+
\text{ .}$$
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3379 |
|
| 3380 |
``` cpp
|
| 3381 |
template<class RealType = double>
|
| 3382 |
class fisher_f_distribution {
|
| 3383 |
public:
|
| 3384 |
// types
|
| 3385 |
using result_type = RealType;
|
| 3386 |
using param_type = unspecified;
|
| 3387 |
|
| 3388 |
// constructor and reset functions
|
| 3389 |
+
fisher_f_distribution() : fisher_f_distribution(1.0) {}
|
| 3390 |
+
explicit fisher_f_distribution(RealType m, RealType n = 1.0);
|
| 3391 |
explicit fisher_f_distribution(const param_type& parm);
|
| 3392 |
void reset();
|
| 3393 |
|
| 3394 |
// generating functions
|
| 3395 |
template<class URBG>
|
|
|
|
| 3406 |
result_type max() const;
|
| 3407 |
};
|
| 3408 |
```
|
| 3409 |
|
| 3410 |
``` cpp
|
| 3411 |
+
explicit fisher_f_distribution(RealType m, RealType n = 1);
|
| 3412 |
```
|
| 3413 |
|
| 3414 |
+
*Preconditions:* 0 < `m` and 0 < `n`.
|
| 3415 |
|
| 3416 |
+
*Remarks:* `m` and `n` correspond to the respective parameters of the
|
| 3417 |
+
distribution.
|
| 3418 |
|
| 3419 |
``` cpp
|
| 3420 |
RealType m() const;
|
| 3421 |
```
|
| 3422 |
|
|
|
|
| 3431 |
constructed.
|
| 3432 |
|
| 3433 |
##### Class template `student_t_distribution` <a id="rand.dist.norm.t">[[rand.dist.norm.t]]</a>
|
| 3434 |
|
| 3435 |
A `student_t_distribution` random number distribution produces random
|
| 3436 |
+
numbers x distributed according to the probability density function
|
| 3437 |
+
$$p(x\,|\,n) = \frac{1}{\sqrt{n \pi}}
|
| 3438 |
+
\cdot \frac{\Gamma\big((n+1)/2\big)}{\Gamma(n/2)}
|
|
|
|
|
|
|
|
|
|
| 3439 |
\cdot \left(1 + \frac{x^2}{n} \right)^{-(n+1)/2}
|
| 3440 |
+
\text{ .}$$
|
| 3441 |
|
| 3442 |
``` cpp
|
| 3443 |
template<class RealType = double>
|
| 3444 |
class student_t_distribution {
|
| 3445 |
public:
|
| 3446 |
// types
|
| 3447 |
using result_type = RealType;
|
| 3448 |
using param_type = unspecified;
|
| 3449 |
|
| 3450 |
// constructor and reset functions
|
| 3451 |
+
student_t_distribution() : student_t_distribution(1.0) {}
|
| 3452 |
+
explicit student_t_distribution(RealType n);
|
| 3453 |
explicit student_t_distribution(const param_type& parm);
|
| 3454 |
void reset();
|
| 3455 |
|
| 3456 |
// generating functions
|
| 3457 |
template<class URBG>
|
|
|
|
| 3467 |
result_type max() const;
|
| 3468 |
};
|
| 3469 |
```
|
| 3470 |
|
| 3471 |
``` cpp
|
| 3472 |
+
explicit student_t_distribution(RealType n);
|
| 3473 |
```
|
| 3474 |
|
| 3475 |
+
*Preconditions:* 0 < `n`.
|
| 3476 |
|
| 3477 |
+
*Remarks:* `n` corresponds to the parameter of the distribution.
|
|
|
|
| 3478 |
|
| 3479 |
``` cpp
|
| 3480 |
RealType n() const;
|
| 3481 |
```
|
| 3482 |
|
|
|
|
| 3487 |
|
| 3488 |
##### Class template `discrete_distribution` <a id="rand.dist.samp.discrete">[[rand.dist.samp.discrete]]</a>
|
| 3489 |
|
| 3490 |
A `discrete_distribution` random number distribution produces random
|
| 3491 |
integers i, 0 ≤ i < n, distributed according to the discrete probability
|
| 3492 |
+
function $$P(i \,|\, p_0, \dotsc, p_{n-1}) = p_i \text{ .}$$
|
|
|
|
|
|
|
|
|
|
| 3493 |
|
| 3494 |
Unless specified otherwise, the distribution parameters are calculated
|
| 3495 |
+
as: pₖ = {wₖ / S} for k = 0, …, n - 1, in which the values wₖ, commonly
|
| 3496 |
+
known as the *weights* , shall be non-negative, non-NaN, and
|
| 3497 |
+
non-infinity. Moreover, the following relation shall hold:
|
| 3498 |
+
$0 < S = w_0 + \dotsb + w_{n - 1}$.
|
| 3499 |
|
| 3500 |
``` cpp
|
| 3501 |
template<class IntType = int>
|
| 3502 |
class discrete_distribution {
|
| 3503 |
public:
|
|
|
|
| 3543 |
``` cpp
|
| 3544 |
template<class InputIterator>
|
| 3545 |
discrete_distribution(InputIterator firstW, InputIterator lastW);
|
| 3546 |
```
|
| 3547 |
|
| 3548 |
+
*Mandates:*
|
| 3549 |
+
`is_convertible_v<iterator_traits<InputIterator>::value_type, double>`
|
| 3550 |
+
is `true`.
|
| 3551 |
+
|
| 3552 |
+
*Preconditions:* `InputIterator` meets the *Cpp17InputIterator*
|
| 3553 |
+
requirements [[input.iterators]]. If `firstW == lastW`, let n = 1 and
|
| 3554 |
+
w₀ = 1. Otherwise, [`firstW`, `lastW`) forms a sequence w of length
|
| 3555 |
+
n > 0.
|
| 3556 |
|
| 3557 |
*Effects:* Constructs a `discrete_distribution` object with
|
| 3558 |
probabilities given by the formula above.
|
| 3559 |
|
| 3560 |
``` cpp
|
|
|
|
| 3566 |
``` cpp
|
| 3567 |
template<class UnaryOperation>
|
| 3568 |
discrete_distribution(size_t nw, double xmin, double xmax, UnaryOperation fw);
|
| 3569 |
```
|
| 3570 |
|
| 3571 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3572 |
+
`true`.
|
| 3573 |
+
|
| 3574 |
+
*Preconditions:* If `nw` = 0, let n = 1, otherwise let n = `nw`. The
|
| 3575 |
+
relation 0 < δ = (`xmax` - `xmin`) / n holds.
|
| 3576 |
|
| 3577 |
*Effects:* Constructs a `discrete_distribution` object with
|
| 3578 |
probabilities given by the formula above, using the following values: If
|
| 3579 |
`nw` = 0, let w₀ = 1. Otherwise, let wₖ = `fw`(`xmin` + k ⋅ δ + δ / 2)
|
| 3580 |
for k = 0, …, n - 1.
|
| 3581 |
|
| 3582 |
+
*Complexity:* The number of invocations of `fw` does not exceed n.
|
| 3583 |
|
| 3584 |
``` cpp
|
| 3585 |
vector<double> probabilities() const;
|
| 3586 |
```
|
| 3587 |
|
|
|
|
| 3592 |
##### Class template `piecewise_constant_distribution` <a id="rand.dist.samp.pconst">[[rand.dist.samp.pconst]]</a>
|
| 3593 |
|
| 3594 |
A `piecewise_constant_distribution` random number distribution produces
|
| 3595 |
random numbers x, b₀ ≤ x < bₙ, uniformly distributed over each
|
| 3596 |
subinterval [ bᵢ, bᵢ₊₁ ) according to the probability density function
|
| 3597 |
+
$$p(x \,|\, b_0, \dotsc, b_n, \; \rho_0, \dotsc, \rho_{n-1}) = \rho_i
|
| 3598 |
+
\text{ , for $b_i \le x < b_{i+1}$.}$$
|
|
|
|
|
|
|
|
|
|
|
|
|
| 3599 |
|
| 3600 |
The n + 1 distribution parameters bᵢ, also known as this distribution’s
|
| 3601 |
+
*interval boundaries* , shall satisfy the relation $b_i < b_{i + 1}$ for
|
| 3602 |
+
i = 0, …, n - 1. Unless specified otherwise, the remaining n
|
| 3603 |
+
distribution parameters are calculated as:
|
| 3604 |
+
$$\rho_k = \frac{w_k}{S \cdot (b_{k+1}-b_k)} \text{ for } k = 0, \dotsc, n - 1 \text{ ,}$$
|
| 3605 |
+
in which the values wₖ, commonly known as the *weights* , shall be
|
| 3606 |
+
non-negative, non-NaN, and non-infinity. Moreover, the following
|
| 3607 |
+
relation shall hold: 0 < S = w₀ + … + wₙ₋₁.
|
|
|
|
|
|
|
| 3608 |
|
| 3609 |
``` cpp
|
| 3610 |
template<class RealType = double>
|
| 3611 |
class piecewise_constant_distribution {
|
| 3612 |
public:
|
|
|
|
| 3654 |
template<class InputIteratorB, class InputIteratorW>
|
| 3655 |
piecewise_constant_distribution(InputIteratorB firstB, InputIteratorB lastB,
|
| 3656 |
InputIteratorW firstW);
|
| 3657 |
```
|
| 3658 |
|
| 3659 |
+
*Mandates:* Both of
|
| 3660 |
+
|
| 3661 |
+
- `is_convertible_v<iterator_traits<InputIteratorB>::value_type, double>`
|
| 3662 |
+
- `is_convertible_v<iterator_traits<InputIteratorW>::value_type, double>`
|
| 3663 |
+
|
| 3664 |
+
are `true`.
|
| 3665 |
+
|
| 3666 |
+
*Preconditions:* `InputIteratorB` and `InputIteratorW` each meet the
|
| 3667 |
+
*Cpp17InputIterator* requirements [[input.iterators]]. If
|
| 3668 |
+
`firstB == lastB` or `++firstB == lastB`, let n = 1, w₀ = 1, b₀ = 0, and
|
| 3669 |
+
b₁ = 1. Otherwise, [`firstB`, `lastB`) forms a sequence b of length n+1,
|
| 3670 |
+
the length of the sequence w starting from `firstW` is at least n, and
|
| 3671 |
+
any wₖ for k ≥ n are ignored by the distribution.
|
| 3672 |
|
| 3673 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3674 |
parameters as specified above.
|
| 3675 |
|
| 3676 |
``` cpp
|
| 3677 |
template<class UnaryOperation>
|
| 3678 |
piecewise_constant_distribution(initializer_list<RealType> bl, UnaryOperation fw);
|
| 3679 |
```
|
| 3680 |
|
| 3681 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3682 |
+
`true`.
|
|
|
|
|
|
|
| 3683 |
|
| 3684 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3685 |
parameters taken or calculated from the following values: If
|
| 3686 |
`bl.size()` < 2, let n = 1, w₀ = 1, b₀ = 0, and b₁ = 1. Otherwise, let
|
| 3687 |
[`bl.begin()`, `bl.end()`) form a sequence b₀, …, bₙ, and let
|
| 3688 |
wₖ = `fw`((bₖ₊₁ + bₖ) / 2) for k = 0, …, n - 1.
|
| 3689 |
|
| 3690 |
+
*Complexity:* The number of invocations of `fw` does not exceed n.
|
| 3691 |
|
| 3692 |
``` cpp
|
| 3693 |
template<class UnaryOperation>
|
| 3694 |
piecewise_constant_distribution(size_t nw, RealType xmin, RealType xmax, UnaryOperation fw);
|
| 3695 |
```
|
| 3696 |
|
| 3697 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3698 |
+
`true`.
|
| 3699 |
+
|
| 3700 |
+
*Preconditions:* If `nw` = 0, let n = 1, otherwise let n = `nw`. The
|
| 3701 |
+
relation 0 < δ = (`xmax` - `xmin`) / n holds.
|
| 3702 |
|
| 3703 |
*Effects:* Constructs a `piecewise_constant_distribution` object with
|
| 3704 |
parameters taken or calculated from the following values: Let
|
| 3705 |
bₖ = `xmin` + k ⋅ δ for k = 0, …, n, and wₖ = `fw`(bₖ + δ / 2) for
|
| 3706 |
k = 0, …, n - 1.
|
| 3707 |
|
| 3708 |
+
*Complexity:* The number of invocations of `fw` does not exceed n.
|
| 3709 |
|
| 3710 |
``` cpp
|
| 3711 |
vector<result_type> intervals() const;
|
| 3712 |
```
|
| 3713 |
|
|
|
|
| 3725 |
|
| 3726 |
##### Class template `piecewise_linear_distribution` <a id="rand.dist.samp.plinear">[[rand.dist.samp.plinear]]</a>
|
| 3727 |
|
| 3728 |
A `piecewise_linear_distribution` random number distribution produces
|
| 3729 |
random numbers x, b₀ ≤ x < bₙ, distributed over each subinterval
|
| 3730 |
+
[bᵢ, bᵢ₊₁) according to the probability density function
|
| 3731 |
+
$$p(x \,|\, b_0, \dotsc, b_n, \; \rho_0, \dotsc, \rho_n)
|
| 3732 |
+
= \rho_{i} \cdot {\frac{b_{i+1} - x}{b_{i+1} - b_i}}
|
| 3733 |
+ \rho_{i+1} \cdot {\frac{x - b_i}{b_{i+1} - b_i}}
|
| 3734 |
+
\text{ , for $b_i \le x < b_{i+1}$.}$$
|
|
|
|
|
|
|
| 3735 |
|
| 3736 |
The n + 1 distribution parameters bᵢ, also known as this distribution’s
|
| 3737 |
*interval boundaries* , shall satisfy the relation bᵢ < bᵢ₊₁ for
|
| 3738 |
i = 0, …, n - 1. Unless specified otherwise, the remaining n + 1
|
| 3739 |
+
distribution parameters are calculated as ρₖ = {wₖ / S} for k = 0, …, n,
|
| 3740 |
+
in which the values wₖ, commonly known as the *weights at boundaries* ,
|
| 3741 |
+
shall be non-negative, non-NaN, and non-infinity. Moreover, the
|
| 3742 |
+
following relation shall hold:
|
| 3743 |
+
$$0 < S = \frac{1}{2} \cdot \sum_{k=0}^{n-1} (w_k + w_{k+1}) \cdot (b_{k+1} - b_k) \text{ .}$$
|
|
|
|
|
|
|
|
|
|
| 3744 |
|
| 3745 |
``` cpp
|
| 3746 |
template<class RealType = double>
|
| 3747 |
class piecewise_linear_distribution {
|
| 3748 |
public:
|
|
|
|
| 3789 |
template<class InputIteratorB, class InputIteratorW>
|
| 3790 |
piecewise_linear_distribution(InputIteratorB firstB, InputIteratorB lastB,
|
| 3791 |
InputIteratorW firstW);
|
| 3792 |
```
|
| 3793 |
|
| 3794 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3795 |
+
`true`.
|
| 3796 |
+
|
| 3797 |
+
*Preconditions:* `InputIteratorB` and `InputIteratorW` each meet the
|
| 3798 |
+
*Cpp17InputIterator* requirements [[input.iterators]]. If
|
| 3799 |
+
`firstB == lastB` or `++firstB == lastB`, let n = 1, ρ₀ = ρ₁ = 1,
|
| 3800 |
+
b₀ = 0, and b₁ = 1. Otherwise, [`firstB`, `lastB`) forms a sequence b of
|
| 3801 |
+
length n+1, the length of the sequence w starting from `firstW` is at
|
| 3802 |
+
least n+1, and any wₖ for k ≥ n + 1 are ignored by the distribution.
|
|
|
|
| 3803 |
|
| 3804 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3805 |
parameters as specified above.
|
| 3806 |
|
| 3807 |
``` cpp
|
| 3808 |
template<class UnaryOperation>
|
| 3809 |
piecewise_linear_distribution(initializer_list<RealType> bl, UnaryOperation fw);
|
| 3810 |
```
|
| 3811 |
|
| 3812 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3813 |
+
`true`.
|
|
|
|
|
|
|
| 3814 |
|
| 3815 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3816 |
parameters taken or calculated from the following values: If
|
| 3817 |
`bl.size()` < 2, let n = 1, ρ₀ = ρ₁ = 1, b₀ = 0, and b₁ = 1. Otherwise,
|
| 3818 |
let [`bl.begin(),` `bl.end()`) form a sequence b₀, …, bₙ, and let
|
| 3819 |
wₖ = `fw`(bₖ) for k = 0, …, n.
|
| 3820 |
|
| 3821 |
+
*Complexity:* The number of invocations of `fw` does not exceed n+1.
|
| 3822 |
|
| 3823 |
``` cpp
|
| 3824 |
template<class UnaryOperation>
|
| 3825 |
piecewise_linear_distribution(size_t nw, RealType xmin, RealType xmax, UnaryOperation fw);
|
| 3826 |
```
|
| 3827 |
|
| 3828 |
+
*Mandates:* `is_invocable_r_v<double, UnaryOperation&, double>` is
|
| 3829 |
+
`true`.
|
| 3830 |
+
|
| 3831 |
+
*Preconditions:* If `nw` = 0, let n = 1, otherwise let n = `nw`. The
|
| 3832 |
+
relation 0 < δ = (`xmax` - `xmin`) / n holds.
|
| 3833 |
|
| 3834 |
*Effects:* Constructs a `piecewise_linear_distribution` object with
|
| 3835 |
parameters taken or calculated from the following values: Let
|
| 3836 |
bₖ = `xmin` + k ⋅ δ for k = 0, …, n, and wₖ = `fw`(bₖ) for k = 0, …, n.
|
| 3837 |
|
| 3838 |
+
*Complexity:* The number of invocations of `fw` does not exceed n+1.
|
| 3839 |
|
| 3840 |
``` cpp
|
| 3841 |
vector<result_type> intervals() const;
|
| 3842 |
```
|
| 3843 |
|
|
|
|
| 3853 |
whose `operator[]` member returns ρₖ when invoked with argument k for
|
| 3854 |
k = 0, …, n.
|
| 3855 |
|
| 3856 |
### Low-quality random number generation <a id="c.math.rand">[[c.math.rand]]</a>
|
| 3857 |
|
| 3858 |
+
[*Note 1*: The header `<cstdlib>` declares the functions described in
|
| 3859 |
+
this subclause. — *end note*]
|
| 3860 |
|
| 3861 |
``` cpp
|
| 3862 |
int rand();
|
| 3863 |
void srand(unsigned int seed);
|
| 3864 |
```
|
|
|
|
| 3866 |
*Effects:* The `rand` and `srand` functions have the semantics specified
|
| 3867 |
in the C standard library.
|
| 3868 |
|
| 3869 |
*Remarks:* The implementation may specify that particular library
|
| 3870 |
functions may call `rand`. It is *implementation-defined* whether the
|
| 3871 |
+
`rand` function may introduce data races [[res.on.data.races]].
|
| 3872 |
|
| 3873 |
[*Note 1*: The other random number generation facilities in this
|
| 3874 |
+
document [[rand]] are often preferable to `rand`, because `rand`’s
|
| 3875 |
+
underlying algorithm is unspecified. Use of `rand` therefore continues
|
| 3876 |
+
to be non-portable, with unpredictable and oft-questionable quality and
|
| 3877 |
+
performance. — *end note*]
|
| 3878 |
|
| 3879 |
+
See also: ISO C 7.22.2
|
| 3880 |
|
| 3881 |
## Numeric arrays <a id="numarray">[[numarray]]</a>
|
| 3882 |
|
| 3883 |
### Header `<valarray>` synopsis <a id="valarray.syn">[[valarray.syn]]</a>
|
| 3884 |
|
|
|
|
| 3895 |
template<class T> class indirect_array; // an indirected array
|
| 3896 |
|
| 3897 |
template<class T> void swap(valarray<T>&, valarray<T>&) noexcept;
|
| 3898 |
|
| 3899 |
template<class T> valarray<T> operator* (const valarray<T>&, const valarray<T>&);
|
| 3900 |
+
template<class T> valarray<T> operator* (const valarray<T>&,
|
| 3901 |
+
const typename valarray<T>::value_type&);
|
| 3902 |
+
template<class T> valarray<T> operator* (const typename valarray<T>::value_type&,
|
| 3903 |
+
const valarray<T>&);
|
| 3904 |
|
| 3905 |
template<class T> valarray<T> operator/ (const valarray<T>&, const valarray<T>&);
|
| 3906 |
+
template<class T> valarray<T> operator/ (const valarray<T>&,
|
| 3907 |
+
const typename valarray<T>::value_type&);
|
| 3908 |
+
template<class T> valarray<T> operator/ (const typename valarray<T>::value_type&,
|
| 3909 |
+
const valarray<T>&);
|
| 3910 |
|
| 3911 |
template<class T> valarray<T> operator% (const valarray<T>&, const valarray<T>&);
|
| 3912 |
+
template<class T> valarray<T> operator% (const valarray<T>&,
|
| 3913 |
+
const typename valarray<T>::value_type&);
|
| 3914 |
+
template<class T> valarray<T> operator% (const typename valarray<T>::value_type&,
|
| 3915 |
+
const valarray<T>&);
|
| 3916 |
|
| 3917 |
template<class T> valarray<T> operator+ (const valarray<T>&, const valarray<T>&);
|
| 3918 |
+
template<class T> valarray<T> operator+ (const valarray<T>&,
|
| 3919 |
+
const typename valarray<T>::value_type&);
|
| 3920 |
+
template<class T> valarray<T> operator+ (const typename valarray<T>::value_type&,
|
| 3921 |
+
const valarray<T>&);
|
| 3922 |
|
| 3923 |
template<class T> valarray<T> operator- (const valarray<T>&, const valarray<T>&);
|
| 3924 |
+
template<class T> valarray<T> operator- (const valarray<T>&,
|
| 3925 |
+
const typename valarray<T>::value_type&);
|
| 3926 |
+
template<class T> valarray<T> operator- (const typename valarray<T>::value_type&,
|
| 3927 |
+
const valarray<T>&);
|
| 3928 |
|
| 3929 |
template<class T> valarray<T> operator^ (const valarray<T>&, const valarray<T>&);
|
| 3930 |
+
template<class T> valarray<T> operator^ (const valarray<T>&,
|
| 3931 |
+
const typename valarray<T>::value_type&);
|
| 3932 |
+
template<class T> valarray<T> operator^ (const typename valarray<T>::value_type&,
|
| 3933 |
+
const valarray<T>&);
|
| 3934 |
|
| 3935 |
template<class T> valarray<T> operator& (const valarray<T>&, const valarray<T>&);
|
| 3936 |
+
template<class T> valarray<T> operator& (const valarray<T>&,
|
| 3937 |
+
const typename valarray<T>::value_type&);
|
| 3938 |
+
template<class T> valarray<T> operator& (const typename valarray<T>::value_type&,
|
| 3939 |
+
const valarray<T>&);
|
| 3940 |
|
| 3941 |
template<class T> valarray<T> operator| (const valarray<T>&, const valarray<T>&);
|
| 3942 |
+
template<class T> valarray<T> operator| (const valarray<T>&,
|
| 3943 |
+
const typename valarray<T>::value_type&);
|
| 3944 |
+
template<class T> valarray<T> operator| (const typename valarray<T>::value_type&,
|
| 3945 |
+
const valarray<T>&);
|
| 3946 |
|
| 3947 |
template<class T> valarray<T> operator<<(const valarray<T>&, const valarray<T>&);
|
| 3948 |
+
template<class T> valarray<T> operator<<(const valarray<T>&,
|
| 3949 |
+
const typename valarray<T>::value_type&);
|
| 3950 |
+
template<class T> valarray<T> operator<<(const typename valarray<T>::value_type&,
|
| 3951 |
+
const valarray<T>&);
|
| 3952 |
|
| 3953 |
template<class T> valarray<T> operator>>(const valarray<T>&, const valarray<T>&);
|
| 3954 |
+
template<class T> valarray<T> operator>>(const valarray<T>&,
|
| 3955 |
+
const typename valarray<T>::value_type&);
|
| 3956 |
+
template<class T> valarray<T> operator>>(const typename valarray<T>::value_type&,
|
| 3957 |
+
const valarray<T>&);
|
| 3958 |
|
| 3959 |
template<class T> valarray<bool> operator&&(const valarray<T>&, const valarray<T>&);
|
| 3960 |
+
template<class T> valarray<bool> operator&&(const valarray<T>&,
|
| 3961 |
+
const typename valarray<T>::value_type&);
|
| 3962 |
+
template<class T> valarray<bool> operator&&(const typename valarray<T>::value_type&,
|
| 3963 |
+
const valarray<T>&);
|
| 3964 |
|
| 3965 |
template<class T> valarray<bool> operator||(const valarray<T>&, const valarray<T>&);
|
| 3966 |
+
template<class T> valarray<bool> operator||(const valarray<T>&,
|
| 3967 |
+
const typename valarray<T>::value_type&);
|
| 3968 |
+
template<class T> valarray<bool> operator||(const typename valarray<T>::value_type&,
|
| 3969 |
+
const valarray<T>&);
|
| 3970 |
|
| 3971 |
+
template<class T> valarray<bool> operator==(const valarray<T>&, const valarray<T>&);
|
| 3972 |
+
template<class T> valarray<bool> operator==(const valarray<T>&,
|
| 3973 |
+
const typename valarray<T>::value_type&);
|
| 3974 |
+
template<class T> valarray<bool> operator==(const typename valarray<T>::value_type&,
|
| 3975 |
+
const valarray<T>&);
|
| 3976 |
+
template<class T> valarray<bool> operator!=(const valarray<T>&, const valarray<T>&);
|
| 3977 |
+
template<class T> valarray<bool> operator!=(const valarray<T>&,
|
| 3978 |
+
const typename valarray<T>::value_type&);
|
| 3979 |
+
template<class T> valarray<bool> operator!=(const typename valarray<T>::value_type&,
|
| 3980 |
+
const valarray<T>&);
|
| 3981 |
|
| 3982 |
+
template<class T> valarray<bool> operator< (const valarray<T>&, const valarray<T>&);
|
| 3983 |
+
template<class T> valarray<bool> operator< (const valarray<T>&,
|
| 3984 |
+
const typename valarray<T>::value_type&);
|
| 3985 |
+
template<class T> valarray<bool> operator< (const typename valarray<T>::value_type&,
|
| 3986 |
+
const valarray<T>&);
|
| 3987 |
+
template<class T> valarray<bool> operator> (const valarray<T>&, const valarray<T>&);
|
| 3988 |
+
template<class T> valarray<bool> operator> (const valarray<T>&,
|
| 3989 |
+
const typename valarray<T>::value_type&);
|
| 3990 |
+
template<class T> valarray<bool> operator> (const typename valarray<T>::value_type&,
|
| 3991 |
+
const valarray<T>&);
|
| 3992 |
+
template<class T> valarray<bool> operator<=(const valarray<T>&, const valarray<T>&);
|
| 3993 |
+
template<class T> valarray<bool> operator<=(const valarray<T>&,
|
| 3994 |
+
const typename valarray<T>::value_type&);
|
| 3995 |
+
template<class T> valarray<bool> operator<=(const typename valarray<T>::value_type&,
|
| 3996 |
+
const valarray<T>&);
|
| 3997 |
+
template<class T> valarray<bool> operator>=(const valarray<T>&, const valarray<T>&);
|
| 3998 |
+
template<class T> valarray<bool> operator>=(const valarray<T>&,
|
| 3999 |
+
const typename valarray<T>::value_type&);
|
| 4000 |
+
template<class T> valarray<bool> operator>=(const typename valarray<T>::value_type&,
|
| 4001 |
+
const valarray<T>&);
|
| 4002 |
|
| 4003 |
template<class T> valarray<T> abs (const valarray<T>&);
|
| 4004 |
template<class T> valarray<T> acos (const valarray<T>&);
|
| 4005 |
template<class T> valarray<T> asin (const valarray<T>&);
|
| 4006 |
template<class T> valarray<T> atan (const valarray<T>&);
|
| 4007 |
|
| 4008 |
template<class T> valarray<T> atan2(const valarray<T>&, const valarray<T>&);
|
| 4009 |
+
template<class T> valarray<T> atan2(const valarray<T>&,
|
| 4010 |
+
const typename valarray<T>::value_type&);
|
| 4011 |
+
template<class T> valarray<T> atan2(const typename valarray<T>::value_type&,
|
| 4012 |
+
const valarray<T>&);
|
| 4013 |
|
| 4014 |
template<class T> valarray<T> cos (const valarray<T>&);
|
| 4015 |
template<class T> valarray<T> cosh (const valarray<T>&);
|
| 4016 |
template<class T> valarray<T> exp (const valarray<T>&);
|
| 4017 |
template<class T> valarray<T> log (const valarray<T>&);
|
| 4018 |
template<class T> valarray<T> log10(const valarray<T>&);
|
| 4019 |
|
| 4020 |
template<class T> valarray<T> pow(const valarray<T>&, const valarray<T>&);
|
| 4021 |
+
template<class T> valarray<T> pow(const valarray<T>&, const typename valarray<T>::value_type&);
|
| 4022 |
+
template<class T> valarray<T> pow(const typename valarray<T>::value_type&, const valarray<T>&);
|
| 4023 |
|
| 4024 |
template<class T> valarray<T> sin (const valarray<T>&);
|
| 4025 |
template<class T> valarray<T> sinh (const valarray<T>&);
|
| 4026 |
template<class T> valarray<T> sqrt (const valarray<T>&);
|
| 4027 |
template<class T> valarray<T> tan (const valarray<T>&);
|
|
|
|
| 4050 |
|
| 4051 |
Implementations introducing such replacement types shall provide
|
| 4052 |
additional functions and operators as follows:
|
| 4053 |
|
| 4054 |
- for every function taking a `const valarray<T>&` other than `begin`
|
| 4055 |
+
and `end` [[valarray.range]], identical functions taking the
|
| 4056 |
replacement types shall be added;
|
| 4057 |
- for every function taking two `const valarray<T>&` arguments,
|
| 4058 |
identical functions taking every combination of `const valarray<T>&`
|
| 4059 |
and replacement types shall be added.
|
| 4060 |
|
| 4061 |
In particular, an implementation shall allow a `valarray<T>` to be
|
| 4062 |
constructed from such replacement types and shall allow assignments and
|
| 4063 |
compound assignments of such types to `valarray<T>`, `slice_array<T>`,
|
| 4064 |
`gslice_array<T>`, `mask_array<T>` and `indirect_array<T>` objects.
|
| 4065 |
|
| 4066 |
+
These library functions are permitted to throw a `bad_alloc`
|
| 4067 |
+
[[bad.alloc]] exception if there are not sufficient resources available
|
| 4068 |
to carry out the operation. Note that the exception is not mandated.
|
| 4069 |
|
| 4070 |
### Class template `valarray` <a id="template.valarray">[[template.valarray]]</a>
|
| 4071 |
|
| 4072 |
+
#### Overview <a id="template.valarray.overview">[[template.valarray.overview]]</a>
|
| 4073 |
|
| 4074 |
``` cpp
|
| 4075 |
namespace std {
|
| 4076 |
template<class T> class valarray {
|
| 4077 |
public:
|
|
|
|
| 4171 |
remainder of [[numarray]]. The illusion of higher dimensionality may be
|
| 4172 |
produced by the familiar idiom of computed indices, together with the
|
| 4173 |
powerful subsetting capabilities provided by the generalized subscript
|
| 4174 |
operators.[^8]
|
| 4175 |
|
| 4176 |
+
#### Constructors <a id="valarray.cons">[[valarray.cons]]</a>
|
|
|
|
|
|
|
|
|
|
| 4177 |
|
| 4178 |
``` cpp
|
| 4179 |
valarray();
|
| 4180 |
```
|
| 4181 |
|
|
|
|
| 4184 |
``` cpp
|
| 4185 |
explicit valarray(size_t n);
|
| 4186 |
```
|
| 4187 |
|
| 4188 |
*Effects:* Constructs a `valarray` that has length `n`. Each element of
|
| 4189 |
+
the array is value-initialized [[dcl.init]].
|
| 4190 |
|
| 4191 |
``` cpp
|
| 4192 |
valarray(const T& v, size_t n);
|
| 4193 |
```
|
| 4194 |
|
|
|
|
| 4197 |
|
| 4198 |
``` cpp
|
| 4199 |
valarray(const T* p, size_t n);
|
| 4200 |
```
|
| 4201 |
|
| 4202 |
+
*Preconditions:* \[`p`, `p + n`) is a valid range.
|
|
|
|
| 4203 |
|
| 4204 |
*Effects:* Constructs a `valarray` that has length `n`. The values of
|
| 4205 |
the elements of the array are initialized with the first `n` values
|
| 4206 |
pointed to by the first argument.[^10]
|
| 4207 |
|
|
|
|
| 4244 |
```
|
| 4245 |
|
| 4246 |
*Effects:* The destructor is applied to every element of `*this`; an
|
| 4247 |
implementation may return all allocated memory.
|
| 4248 |
|
| 4249 |
+
#### Assignment <a id="valarray.assign">[[valarray.assign]]</a>
|
| 4250 |
|
| 4251 |
``` cpp
|
| 4252 |
valarray& operator=(const valarray& v);
|
| 4253 |
```
|
| 4254 |
|
|
|
|
| 4256 |
the corresponding element of `v`. If the length of `v` is not equal to
|
| 4257 |
the length of `*this`, resizes `*this` to make the two arrays the same
|
| 4258 |
length, as if by calling `resize(v.size())`, before performing the
|
| 4259 |
assignment.
|
| 4260 |
|
| 4261 |
+
*Ensures:* `size() == v.size()`.
|
| 4262 |
|
| 4263 |
*Returns:* `*this`.
|
| 4264 |
|
| 4265 |
``` cpp
|
| 4266 |
valarray& operator=(valarray&& v) noexcept;
|
|
|
|
| 4292 |
valarray& operator=(const gslice_array<T>&);
|
| 4293 |
valarray& operator=(const mask_array<T>&);
|
| 4294 |
valarray& operator=(const indirect_array<T>&);
|
| 4295 |
```
|
| 4296 |
|
| 4297 |
+
*Preconditions:* The length of the array to which the argument refers
|
| 4298 |
+
equals `size()`. The value of an element in the left-hand side of a
|
| 4299 |
+
`valarray` assignment operator does not depend on the value of another
|
| 4300 |
+
element in that left-hand side.
|
| 4301 |
|
| 4302 |
These operators allow the results of a generalized subscripting
|
| 4303 |
operation to be assigned directly to a `valarray`.
|
| 4304 |
|
| 4305 |
+
#### Element access <a id="valarray.access">[[valarray.access]]</a>
|
| 4306 |
|
| 4307 |
``` cpp
|
| 4308 |
const T& operator[](size_t n) const;
|
| 4309 |
T& operator[](size_t n);
|
| 4310 |
```
|
| 4311 |
|
| 4312 |
+
*Preconditions:* `n < size()` is `true`.
|
| 4313 |
|
| 4314 |
*Returns:* A reference to the corresponding element of the array.
|
| 4315 |
|
| 4316 |
[*Note 1*: The expression `(a[i] = q, a[i]) == q` evaluates to `true`
|
| 4317 |
for any non-constant `valarray<T> a`, any `T q`, and for any `size_t i`
|
| 4318 |
such that the value of `i` is less than the length of
|
| 4319 |
`a`. — *end note*]
|
| 4320 |
|
| 4321 |
+
*Remarks:* The expression `addressof(a[i+j]) == addressof(a[i]) + j`
|
| 4322 |
+
evaluates to `true` for all `size_t i` and `size_t j` such that
|
| 4323 |
+
`i+j < a.size()`.
|
| 4324 |
|
| 4325 |
+
The expression `addressof(a[i]) != addressof(b[j])` evaluates to `true`
|
| 4326 |
+
for any two arrays `a` and `b` and for any `size_t i` and `size_t j`
|
| 4327 |
+
such that `i < a.size()` and `j < b.size()`.
|
| 4328 |
|
| 4329 |
[*Note 2*: This property indicates an absence of aliasing and may be
|
| 4330 |
used to advantage by optimizing compilers. Compilers may take advantage
|
| 4331 |
of inlining, constant propagation, loop fusion, tracking of pointers
|
| 4332 |
obtained from `operator new`, and other techniques to generate efficient
|
| 4333 |
`valarray`s. — *end note*]
|
| 4334 |
|
| 4335 |
The reference returned by the subscript operator for an array shall be
|
| 4336 |
+
valid until the member function `resize(size_t, T)` [[valarray.members]]
|
| 4337 |
+
is called for that array or until the lifetime of that array ends,
|
| 4338 |
+
whichever happens first.
|
| 4339 |
|
| 4340 |
+
#### Subset operations <a id="valarray.sub">[[valarray.sub]]</a>
|
| 4341 |
|
| 4342 |
The member `operator[]` is overloaded to provide several ways to select
|
| 4343 |
sequences of elements from among those controlled by `*this`. Each of
|
| 4344 |
these operations returns a subset of the array. The const-qualified
|
| 4345 |
versions return this subset as a new `valarray` object. The non-const
|
| 4346 |
versions return a class template object which has reference semantics to
|
| 4347 |
the original array, working in conjunction with various overloads of
|
| 4348 |
`operator=` and other assigning operators to allow selective replacement
|
| 4349 |
(slicing) of the controlled sequence. In each case the selected
|
| 4350 |
+
element(s) shall exist.
|
| 4351 |
|
| 4352 |
``` cpp
|
| 4353 |
valarray operator[](slice slicearr) const;
|
| 4354 |
```
|
| 4355 |
|
|
|
|
| 4496 |
// v0 == valarray<char>("abCDeBgAEjklmnop", 16)
|
| 4497 |
```
|
| 4498 |
|
| 4499 |
— *end example*]
|
| 4500 |
|
| 4501 |
+
#### Unary operators <a id="valarray.unary">[[valarray.unary]]</a>
|
| 4502 |
|
| 4503 |
``` cpp
|
| 4504 |
valarray operator+() const;
|
| 4505 |
valarray operator-() const;
|
| 4506 |
valarray operator~() const;
|
| 4507 |
valarray<bool> operator!() const;
|
| 4508 |
```
|
| 4509 |
|
| 4510 |
+
*Mandates:* The indicated operator can be applied to operands of type
|
| 4511 |
+
`T` and returns a value of type `T` (`bool` for `operator!`) or which
|
| 4512 |
+
may be unambiguously implicitly converted to type `T` (`bool` for
|
| 4513 |
+
`operator!`).
|
|
|
|
| 4514 |
|
| 4515 |
*Returns:* A `valarray` whose length is `size()`. Each element of the
|
| 4516 |
returned array is initialized with the result of applying the indicated
|
| 4517 |
operator to the corresponding element of the array.
|
| 4518 |
|
| 4519 |
+
#### Compound assignment <a id="valarray.cassign">[[valarray.cassign]]</a>
|
| 4520 |
|
| 4521 |
``` cpp
|
| 4522 |
valarray& operator*= (const valarray& v);
|
| 4523 |
valarray& operator/= (const valarray& v);
|
| 4524 |
valarray& operator%= (const valarray& v);
|
|
|
|
| 4529 |
valarray& operator|= (const valarray& v);
|
| 4530 |
valarray& operator<<=(const valarray& v);
|
| 4531 |
valarray& operator>>=(const valarray& v);
|
| 4532 |
```
|
| 4533 |
|
| 4534 |
+
*Mandates:* The indicated operator can be applied to two operands of
|
| 4535 |
+
type `T`.
|
| 4536 |
+
|
| 4537 |
+
*Preconditions:* `size() == v.size()` is `true`.
|
| 4538 |
+
|
| 4539 |
+
The value of an element in the left-hand side of a valarray compound
|
| 4540 |
+
assignment operator does not depend on the value of another element in
|
| 4541 |
+
that left hand side.
|
| 4542 |
|
| 4543 |
*Effects:* Each of these operators performs the indicated operation on
|
| 4544 |
each of the elements of `*this` and the corresponding element of `v`.
|
| 4545 |
|
| 4546 |
*Returns:* `*this`.
|
|
|
|
| 4559 |
valarray& operator|= (const T& v);
|
| 4560 |
valarray& operator<<=(const T& v);
|
| 4561 |
valarray& operator>>=(const T& v);
|
| 4562 |
```
|
| 4563 |
|
| 4564 |
+
*Mandates:* The indicated operator can be applied to two operands of
|
| 4565 |
+
type `T`.
|
|
|
|
| 4566 |
|
| 4567 |
*Effects:* Each of these operators applies the indicated operation to
|
| 4568 |
each element of `*this` and `v`.
|
| 4569 |
|
| 4570 |
*Returns:* `*this`
|
| 4571 |
|
| 4572 |
*Remarks:* The appearance of an array on the left-hand side of a
|
| 4573 |
compound assignment does not invalidate references or pointers to the
|
| 4574 |
elements of the array.
|
| 4575 |
|
| 4576 |
+
#### Member functions <a id="valarray.members">[[valarray.members]]</a>
|
| 4577 |
|
| 4578 |
``` cpp
|
| 4579 |
void swap(valarray& v) noexcept;
|
| 4580 |
```
|
| 4581 |
|
|
|
|
| 4594 |
|
| 4595 |
``` cpp
|
| 4596 |
T sum() const;
|
| 4597 |
```
|
| 4598 |
|
| 4599 |
+
*Mandates:* `operator+=` can be applied to operands of type `T`.
|
| 4600 |
+
|
| 4601 |
+
*Preconditions:* `size() > 0` is `true`.
|
| 4602 |
|
| 4603 |
*Returns:* The sum of all the elements of the array. If the array has
|
| 4604 |
length 1, returns the value of element 0. Otherwise, the returned value
|
| 4605 |
is calculated by applying `operator+=` to a copy of an element of the
|
| 4606 |
array and all other elements of the array in an unspecified order.
|
| 4607 |
|
| 4608 |
``` cpp
|
| 4609 |
T min() const;
|
| 4610 |
```
|
| 4611 |
|
| 4612 |
+
*Preconditions:* `size() > 0` is `true`.
|
| 4613 |
|
| 4614 |
*Returns:* The minimum value contained in `*this`. For an array of
|
| 4615 |
length 1, the value of element 0 is returned. For all other array
|
| 4616 |
lengths, the determination is made using `operator<`.
|
| 4617 |
|
| 4618 |
``` cpp
|
| 4619 |
T max() const;
|
| 4620 |
```
|
| 4621 |
|
| 4622 |
+
*Preconditions:* `size() > 0` is `true`.
|
| 4623 |
|
| 4624 |
*Returns:* The maximum value contained in `*this`. For an array of
|
| 4625 |
length 1, the value of element 0 is returned. For all other array
|
| 4626 |
lengths, the determination is made using `operator<`.
|
| 4627 |
|
|
|
|
| 4636 |
[*Note 1*: If element zero is taken as the leftmost element, a positive
|
| 4637 |
value of `n` shifts the elements left `n` places, with zero
|
| 4638 |
fill. — *end note*]
|
| 4639 |
|
| 4640 |
[*Example 1*: If the argument has the value -2, the first two elements
|
| 4641 |
+
of the result will be value-initialized [[dcl.init]]; the third element
|
| 4642 |
+
of the result will be assigned the value of the first element of the
|
| 4643 |
+
argument; etc. — *end example*]
|
| 4644 |
|
| 4645 |
``` cpp
|
| 4646 |
valarray cshift(int n) const;
|
| 4647 |
```
|
| 4648 |
|
|
|
|
| 4668 |
assigns to each element the value of the second argument. Resizing
|
| 4669 |
invalidates all pointers and references to elements in the array.
|
| 4670 |
|
| 4671 |
### `valarray` non-member operations <a id="valarray.nonmembers">[[valarray.nonmembers]]</a>
|
| 4672 |
|
| 4673 |
+
#### Binary operators <a id="valarray.binary">[[valarray.binary]]</a>
|
| 4674 |
|
| 4675 |
``` cpp
|
| 4676 |
+
template<class T> valarray<T> operator* (const valarray<T>&, const valarray<T>&);
|
| 4677 |
+
template<class T> valarray<T> operator/ (const valarray<T>&, const valarray<T>&);
|
| 4678 |
+
template<class T> valarray<T> operator% (const valarray<T>&, const valarray<T>&);
|
| 4679 |
+
template<class T> valarray<T> operator+ (const valarray<T>&, const valarray<T>&);
|
| 4680 |
+
template<class T> valarray<T> operator- (const valarray<T>&, const valarray<T>&);
|
| 4681 |
+
template<class T> valarray<T> operator^ (const valarray<T>&, const valarray<T>&);
|
| 4682 |
+
template<class T> valarray<T> operator& (const valarray<T>&, const valarray<T>&);
|
| 4683 |
+
template<class T> valarray<T> operator| (const valarray<T>&, const valarray<T>&);
|
| 4684 |
+
template<class T> valarray<T> operator<<(const valarray<T>&, const valarray<T>&);
|
| 4685 |
+
template<class T> valarray<T> operator>>(const valarray<T>&, const valarray<T>&);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 4686 |
```
|
| 4687 |
|
| 4688 |
+
*Mandates:* The indicated operator can be applied to operands of type
|
| 4689 |
+
`T` and returns a value of type `T` or which can be unambiguously
|
| 4690 |
+
implicitly converted to `T`.
|
| 4691 |
+
|
| 4692 |
+
*Preconditions:* The argument arrays have the same length.
|
| 4693 |
|
| 4694 |
*Returns:* A `valarray` whose length is equal to the lengths of the
|
| 4695 |
argument arrays. Each element of the returned array is initialized with
|
| 4696 |
the result of applying the indicated operator to the corresponding
|
| 4697 |
elements of the argument arrays.
|
| 4698 |
|
| 4699 |
``` cpp
|
| 4700 |
+
template<class T> valarray<T> operator* (const valarray<T>&,
|
| 4701 |
+
const typename valarray<T>::value_type&);
|
| 4702 |
+
template<class T> valarray<T> operator* (const typename valarray<T>::value_type&,
|
| 4703 |
+
const valarray<T>&);
|
| 4704 |
+
template<class T> valarray<T> operator/ (const valarray<T>&,
|
| 4705 |
+
const typename valarray<T>::value_type&);
|
| 4706 |
+
template<class T> valarray<T> operator/ (const typename valarray<T>::value_type&,
|
| 4707 |
+
const valarray<T>&);
|
| 4708 |
+
template<class T> valarray<T> operator% (const valarray<T>&,
|
| 4709 |
+
const typename valarray<T>::value_type&);
|
| 4710 |
+
template<class T> valarray<T> operator% (const typename valarray<T>::value_type&,
|
| 4711 |
+
const valarray<T>&);
|
| 4712 |
+
template<class T> valarray<T> operator+ (const valarray<T>&,
|
| 4713 |
+
const typename valarray<T>::value_type&);
|
| 4714 |
+
template<class T> valarray<T> operator+ (const typename valarray<T>::value_type&,
|
| 4715 |
+
const valarray<T>&);
|
| 4716 |
+
template<class T> valarray<T> operator- (const valarray<T>&,
|
| 4717 |
+
const typename valarray<T>::value_type&);
|
| 4718 |
+
template<class T> valarray<T> operator- (const typename valarray<T>::value_type&,
|
| 4719 |
+
const valarray<T>&);
|
| 4720 |
+
template<class T> valarray<T> operator^ (const valarray<T>&,
|
| 4721 |
+
const typename valarray<T>::value_type&);
|
| 4722 |
+
template<class T> valarray<T> operator^ (const typename valarray<T>::value_type&,
|
| 4723 |
+
const valarray<T>&);
|
| 4724 |
+
template<class T> valarray<T> operator& (const valarray<T>&,
|
| 4725 |
+
const typename valarray<T>::value_type&);
|
| 4726 |
+
template<class T> valarray<T> operator& (const typename valarray<T>::value_type&,
|
| 4727 |
+
const valarray<T>&);
|
| 4728 |
+
template<class T> valarray<T> operator| (const valarray<T>&,
|
| 4729 |
+
const typename valarray<T>::value_type&);
|
| 4730 |
+
template<class T> valarray<T> operator| (const typename valarray<T>::value_type&,
|
| 4731 |
+
const valarray<T>&);
|
| 4732 |
+
template<class T> valarray<T> operator<<(const valarray<T>&,
|
| 4733 |
+
const typename valarray<T>::value_type&);
|
| 4734 |
+
template<class T> valarray<T> operator<<(const typename valarray<T>::value_type&,
|
| 4735 |
+
const valarray<T>&);
|
| 4736 |
+
template<class T> valarray<T> operator>>(const valarray<T>&,
|
| 4737 |
+
const typename valarray<T>::value_type&);
|
| 4738 |
+
template<class T> valarray<T> operator>>(const typename valarray<T>::value_type&,
|
| 4739 |
+
const valarray<T>&);
|
| 4740 |
```
|
| 4741 |
|
| 4742 |
+
*Mandates:* The indicated operator can be applied to operands of type
|
| 4743 |
+
`T` and returns a value of type `T` or which can be unambiguously
|
| 4744 |
+
implicitly converted to `T`.
|
|
|
|
| 4745 |
|
| 4746 |
*Returns:* A `valarray` whose length is equal to the length of the array
|
| 4747 |
argument. Each element of the returned array is initialized with the
|
| 4748 |
result of applying the indicated operator to the corresponding element
|
| 4749 |
of the array argument and the non-array argument.
|
| 4750 |
|
| 4751 |
+
#### Logical operators <a id="valarray.comparison">[[valarray.comparison]]</a>
|
| 4752 |
|
| 4753 |
``` cpp
|
| 4754 |
+
template<class T> valarray<bool> operator==(const valarray<T>&, const valarray<T>&);
|
| 4755 |
+
template<class T> valarray<bool> operator!=(const valarray<T>&, const valarray<T>&);
|
| 4756 |
+
template<class T> valarray<bool> operator< (const valarray<T>&, const valarray<T>&);
|
| 4757 |
+
template<class T> valarray<bool> operator> (const valarray<T>&, const valarray<T>&);
|
| 4758 |
+
template<class T> valarray<bool> operator<=(const valarray<T>&, const valarray<T>&);
|
| 4759 |
+
template<class T> valarray<bool> operator>=(const valarray<T>&, const valarray<T>&);
|
| 4760 |
+
template<class T> valarray<bool> operator&&(const valarray<T>&, const valarray<T>&);
|
| 4761 |
+
template<class T> valarray<bool> operator||(const valarray<T>&, const valarray<T>&);
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 4762 |
```
|
| 4763 |
|
| 4764 |
+
*Mandates:* The indicated operator can be applied to operands of type
|
| 4765 |
+
`T` and returns a value of type `bool` or which can be unambiguously
|
| 4766 |
+
implicitly converted to `bool`.
|
| 4767 |
+
|
| 4768 |
+
*Preconditions:* The two array arguments have the same length.
|
| 4769 |
|
| 4770 |
*Returns:* A `valarray<bool>` whose length is equal to the length of the
|
| 4771 |
array arguments. Each element of the returned array is initialized with
|
| 4772 |
the result of applying the indicated operator to the corresponding
|
| 4773 |
elements of the argument arrays.
|
| 4774 |
|
| 4775 |
``` cpp
|
| 4776 |
+
template<class T> valarray<bool> operator==(const valarray<T>&,
|
| 4777 |
+
const typename valarray<T>::value_type&);
|
| 4778 |
+
template<class T> valarray<bool> operator==(const typename valarray<T>::value_type&,
|
| 4779 |
+
const valarray<T>&);
|
| 4780 |
+
template<class T> valarray<bool> operator!=(const valarray<T>&,
|
| 4781 |
+
const typename valarray<T>::value_type&);
|
| 4782 |
+
template<class T> valarray<bool> operator!=(const typename valarray<T>::value_type&,
|
| 4783 |
+
const valarray<T>&);
|
| 4784 |
+
template<class T> valarray<bool> operator< (const valarray<T>&,
|
| 4785 |
+
const typename valarray<T>::value_type&);
|
| 4786 |
+
template<class T> valarray<bool> operator< (const typename valarray<T>::value_type&,
|
| 4787 |
+
const valarray<T>&);
|
| 4788 |
+
template<class T> valarray<bool> operator> (const valarray<T>&,
|
| 4789 |
+
const typename valarray<T>::value_type&);
|
| 4790 |
+
template<class T> valarray<bool> operator> (const typename valarray<T>::value_type&,
|
| 4791 |
+
const valarray<T>&);
|
| 4792 |
+
template<class T> valarray<bool> operator<=(const valarray<T>&,
|
| 4793 |
+
const typename valarray<T>::value_type&);
|
| 4794 |
+
template<class T> valarray<bool> operator<=(const typename valarray<T>::value_type&,
|
| 4795 |
+
const valarray<T>&);
|
| 4796 |
+
template<class T> valarray<bool> operator>=(const valarray<T>&,
|
| 4797 |
+
const typename valarray<T>::value_type&);
|
| 4798 |
+
template<class T> valarray<bool> operator>=(const typename valarray<T>::value_type&,
|
| 4799 |
+
const valarray<T>&);
|
| 4800 |
+
template<class T> valarray<bool> operator&&(const valarray<T>&,
|
| 4801 |
+
const typename valarray<T>::value_type&);
|
| 4802 |
+
template<class T> valarray<bool> operator&&(const typename valarray<T>::value_type&,
|
| 4803 |
+
const valarray<T>&);
|
| 4804 |
+
template<class T> valarray<bool> operator||(const valarray<T>&,
|
| 4805 |
+
const typename valarray<T>::value_type&);
|
| 4806 |
+
template<class T> valarray<bool> operator||(const typename valarray<T>::value_type&,
|
| 4807 |
+
const valarray<T>&);
|
| 4808 |
```
|
| 4809 |
|
| 4810 |
+
*Mandates:* The indicated operator can be applied to operands of type
|
| 4811 |
+
`T` and returns a value of type `bool` or which can be unambiguously
|
| 4812 |
+
implicitly converted to `bool`.
|
|
|
|
| 4813 |
|
| 4814 |
*Returns:* A `valarray<bool>` whose length is equal to the length of the
|
| 4815 |
array argument. Each element of the returned array is initialized with
|
| 4816 |
the result of applying the indicated operator to the corresponding
|
| 4817 |
element of the array and the non-array argument.
|
| 4818 |
|
| 4819 |
+
#### Transcendentals <a id="valarray.transcend">[[valarray.transcend]]</a>
|
| 4820 |
|
| 4821 |
``` cpp
|
| 4822 |
template<class T> valarray<T> abs (const valarray<T>&);
|
| 4823 |
template<class T> valarray<T> acos (const valarray<T>&);
|
| 4824 |
template<class T> valarray<T> asin (const valarray<T>&);
|
| 4825 |
template<class T> valarray<T> atan (const valarray<T>&);
|
| 4826 |
+
template<class T> valarray<T> atan2(const valarray<T>&, const valarray<T>&);
|
| 4827 |
+
template<class T> valarray<T> atan2(const valarray<T>&, const typename valarray<T>::value_type&);
|
| 4828 |
+
template<class T> valarray<T> atan2(const typename valarray<T>::value_type&, const valarray<T>&);
|
|
|
|
| 4829 |
template<class T> valarray<T> cos (const valarray<T>&);
|
| 4830 |
template<class T> valarray<T> cosh (const valarray<T>&);
|
| 4831 |
template<class T> valarray<T> exp (const valarray<T>&);
|
| 4832 |
template<class T> valarray<T> log (const valarray<T>&);
|
| 4833 |
template<class T> valarray<T> log10(const valarray<T>&);
|
| 4834 |
+
template<class T> valarray<T> pow (const valarray<T>&, const valarray<T>&);
|
| 4835 |
+
template<class T> valarray<T> pow (const valarray<T>&, const typename valarray<T>::value_type&);
|
| 4836 |
+
template<class T> valarray<T> pow (const typename valarray<T>::value_type&, const valarray<T>&);
|
|
|
|
| 4837 |
template<class T> valarray<T> sin (const valarray<T>&);
|
| 4838 |
template<class T> valarray<T> sinh (const valarray<T>&);
|
| 4839 |
template<class T> valarray<T> sqrt (const valarray<T>&);
|
| 4840 |
template<class T> valarray<T> tan (const valarray<T>&);
|
| 4841 |
template<class T> valarray<T> tanh (const valarray<T>&);
|
| 4842 |
```
|
| 4843 |
|
| 4844 |
+
*Mandates:* A unique function with the indicated name can be applied
|
| 4845 |
+
(unqualified) to an operand of type `T`. This function returns a value
|
| 4846 |
+
of type `T` or which can be unambiguously implicitly converted to type
|
| 4847 |
+
`T`.
|
| 4848 |
|
| 4849 |
+
#### Specialized algorithms <a id="valarray.special">[[valarray.special]]</a>
|
| 4850 |
|
| 4851 |
``` cpp
|
| 4852 |
template<class T> void swap(valarray<T>& x, valarray<T>& y) noexcept;
|
| 4853 |
```
|
| 4854 |
|
| 4855 |
*Effects:* Equivalent to `x.swap(y)`.
|
| 4856 |
|
| 4857 |
### Class `slice` <a id="class.slice">[[class.slice]]</a>
|
| 4858 |
|
| 4859 |
+
#### Overview <a id="class.slice.overview">[[class.slice.overview]]</a>
|
| 4860 |
|
| 4861 |
``` cpp
|
| 4862 |
namespace std {
|
| 4863 |
class slice {
|
| 4864 |
public:
|
|
|
|
| 4866 |
slice(size_t, size_t, size_t);
|
| 4867 |
|
| 4868 |
size_t start() const;
|
| 4869 |
size_t size() const;
|
| 4870 |
size_t stride() const;
|
| 4871 |
+
|
| 4872 |
+
friend bool operator==(const slice& x, const slice& y);
|
| 4873 |
};
|
| 4874 |
}
|
| 4875 |
```
|
| 4876 |
|
| 4877 |
The `slice` class represents a BLAS-like slice from an array. Such a
|
| 4878 |
slice is specified by a starting index, a length, and a stride.[^12]
|
| 4879 |
|
| 4880 |
+
#### Constructors <a id="cons.slice">[[cons.slice]]</a>
|
| 4881 |
|
| 4882 |
``` cpp
|
| 4883 |
slice();
|
| 4884 |
slice(size_t start, size_t length, size_t stride);
|
| 4885 |
slice(const slice&);
|
|
|
|
| 4889 |
constructor is provided only to permit the declaration of arrays of
|
| 4890 |
slices. The constructor with arguments for a slice takes a start,
|
| 4891 |
length, and stride parameter.
|
| 4892 |
|
| 4893 |
[*Example 1*: `slice(3, 8, 2)` constructs a slice which selects
|
| 4894 |
+
elements 3, 5, 7, …, 17 from an array. — *end example*]
|
| 4895 |
|
| 4896 |
+
#### Access functions <a id="slice.access">[[slice.access]]</a>
|
| 4897 |
|
| 4898 |
``` cpp
|
| 4899 |
size_t start() const;
|
| 4900 |
size_t size() const;
|
| 4901 |
size_t stride() const;
|
|
|
|
| 4903 |
|
| 4904 |
*Returns:* The start, length, or stride specified by a `slice` object.
|
| 4905 |
|
| 4906 |
*Complexity:* Constant time.
|
| 4907 |
|
| 4908 |
+
#### Operators <a id="slice.ops">[[slice.ops]]</a>
|
| 4909 |
+
|
| 4910 |
+
``` cpp
|
| 4911 |
+
friend bool operator==(const slice& x, const slice& y);
|
| 4912 |
+
```
|
| 4913 |
+
|
| 4914 |
+
*Effects:* Equivalent to:
|
| 4915 |
+
|
| 4916 |
+
``` cpp
|
| 4917 |
+
return x.start() == y.start() && x.size() == y.size() && x.stride() == y.stride();
|
| 4918 |
+
```
|
| 4919 |
+
|
| 4920 |
### Class template `slice_array` <a id="template.slice.array">[[template.slice.array]]</a>
|
| 4921 |
|
| 4922 |
+
#### Overview <a id="template.slice.array.overview">[[template.slice.array.overview]]</a>
|
| 4923 |
|
| 4924 |
``` cpp
|
| 4925 |
namespace std {
|
| 4926 |
template<class T> class slice_array {
|
| 4927 |
public:
|
|
|
|
| 4947 |
slice_array() = delete; // as implied by declaring copy constructor above
|
| 4948 |
};
|
| 4949 |
}
|
| 4950 |
```
|
| 4951 |
|
| 4952 |
+
This template is a helper template used by the `slice` subscript
|
| 4953 |
+
operator
|
| 4954 |
|
| 4955 |
``` cpp
|
| 4956 |
slice_array<T> valarray<T>::operator[](slice);
|
| 4957 |
```
|
| 4958 |
|
| 4959 |
It has reference semantics to a subset of an array specified by a
|
| 4960 |
`slice` object.
|
| 4961 |
|
| 4962 |
[*Example 1*: The expression `a[slice(1, 5, 3)] = b;` has the effect of
|
| 4963 |
assigning the elements of `b` to a slice of the elements in `a`. For the
|
| 4964 |
+
slice shown, the elements selected from `a` are
|
| 4965 |
+
1, 4, …, 13. — *end example*]
|
| 4966 |
|
| 4967 |
+
#### Assignment <a id="slice.arr.assign">[[slice.arr.assign]]</a>
|
| 4968 |
|
| 4969 |
``` cpp
|
| 4970 |
void operator=(const valarray<T>&) const;
|
| 4971 |
const slice_array& operator=(const slice_array&) const;
|
| 4972 |
```
|
| 4973 |
|
| 4974 |
These assignment operators have reference semantics, assigning the
|
| 4975 |
values of the argument array elements to selected elements of the
|
| 4976 |
`valarray<T>` object to which the `slice_array` object refers.
|
| 4977 |
|
| 4978 |
+
#### Compound assignment <a id="slice.arr.comp.assign">[[slice.arr.comp.assign]]</a>
|
| 4979 |
|
| 4980 |
``` cpp
|
| 4981 |
void operator*= (const valarray<T>&) const;
|
| 4982 |
void operator/= (const valarray<T>&) const;
|
| 4983 |
void operator%= (const valarray<T>&) const;
|
|
|
|
| 4993 |
These compound assignments have reference semantics, applying the
|
| 4994 |
indicated operation to the elements of the argument array and selected
|
| 4995 |
elements of the `valarray<T>` object to which the `slice_array` object
|
| 4996 |
refers.
|
| 4997 |
|
| 4998 |
+
#### Fill function <a id="slice.arr.fill">[[slice.arr.fill]]</a>
|
| 4999 |
|
| 5000 |
``` cpp
|
| 5001 |
void operator=(const T&) const;
|
| 5002 |
```
|
| 5003 |
|
|
|
|
| 5005 |
argument to the elements of the `valarray<T>` object to which the
|
| 5006 |
`slice_array` object refers.
|
| 5007 |
|
| 5008 |
### The `gslice` class <a id="class.gslice">[[class.gslice]]</a>
|
| 5009 |
|
| 5010 |
+
#### Overview <a id="class.gslice.overview">[[class.gslice.overview]]</a>
|
| 5011 |
|
| 5012 |
``` cpp
|
| 5013 |
namespace std {
|
| 5014 |
class gslice {
|
| 5015 |
public:
|
|
|
|
| 5063 |
— *end example*]
|
| 5064 |
|
| 5065 |
If a degenerate slice is used as the argument to the non-`const` version
|
| 5066 |
of `operator[](const gslice&)`, the behavior is undefined.
|
| 5067 |
|
| 5068 |
+
#### Constructors <a id="gslice.cons">[[gslice.cons]]</a>
|
| 5069 |
|
| 5070 |
``` cpp
|
| 5071 |
gslice();
|
| 5072 |
gslice(size_t start, const valarray<size_t>& lengths,
|
| 5073 |
const valarray<size_t>& strides);
|
|
|
|
| 5075 |
```
|
| 5076 |
|
| 5077 |
The default constructor is equivalent to
|
| 5078 |
`gslice(0, valarray<size_t>(), valarray<size_t>())`. The constructor
|
| 5079 |
with arguments builds a `gslice` based on a specification of start,
|
| 5080 |
+
lengths, and strides, as explained in the previous subclause.
|
| 5081 |
|
| 5082 |
+
#### Access functions <a id="gslice.access">[[gslice.access]]</a>
|
| 5083 |
|
| 5084 |
``` cpp
|
| 5085 |
size_t start() const;
|
| 5086 |
valarray<size_t> size() const;
|
| 5087 |
valarray<size_t> stride() const;
|
|
|
|
| 5093 |
*Complexity:* `start()` is constant time. `size()` and `stride()` are
|
| 5094 |
linear in the number of strides.
|
| 5095 |
|
| 5096 |
### Class template `gslice_array` <a id="template.gslice.array">[[template.gslice.array]]</a>
|
| 5097 |
|
| 5098 |
+
#### Overview <a id="template.gslice.array.overview">[[template.gslice.array.overview]]</a>
|
| 5099 |
|
| 5100 |
``` cpp
|
| 5101 |
namespace std {
|
| 5102 |
template<class T> class gslice_array {
|
| 5103 |
public:
|
|
|
|
| 5123 |
gslice_array() = delete; // as implied by declaring copy constructor above
|
| 5124 |
};
|
| 5125 |
}
|
| 5126 |
```
|
| 5127 |
|
| 5128 |
+
This template is a helper template used by the `gslice` subscript
|
| 5129 |
operator
|
| 5130 |
|
| 5131 |
``` cpp
|
| 5132 |
gslice_array<T> valarray<T>::operator[](const gslice&);
|
| 5133 |
```
|
| 5134 |
|
| 5135 |
It has reference semantics to a subset of an array specified by a
|
| 5136 |
+
`gslice` object. Thus, the expression `a[gslice(1, length, stride)] = b`
|
| 5137 |
+
has the effect of assigning the elements of `b` to a generalized slice
|
| 5138 |
+
of the elements in `a`.
|
| 5139 |
|
| 5140 |
+
#### Assignment <a id="gslice.array.assign">[[gslice.array.assign]]</a>
|
|
|
|
|
|
|
|
|
|
|
|
|
| 5141 |
|
| 5142 |
``` cpp
|
| 5143 |
void operator=(const valarray<T>&) const;
|
| 5144 |
const gslice_array& operator=(const gslice_array&) const;
|
| 5145 |
```
|
| 5146 |
|
| 5147 |
These assignment operators have reference semantics, assigning the
|
| 5148 |
values of the argument array elements to selected elements of the
|
| 5149 |
`valarray<T>` object to which the `gslice_array` refers.
|
| 5150 |
|
| 5151 |
+
#### Compound assignment <a id="gslice.array.comp.assign">[[gslice.array.comp.assign]]</a>
|
| 5152 |
|
| 5153 |
``` cpp
|
| 5154 |
void operator*= (const valarray<T>&) const;
|
| 5155 |
void operator/= (const valarray<T>&) const;
|
| 5156 |
void operator%= (const valarray<T>&) const;
|
|
|
|
| 5166 |
These compound assignments have reference semantics, applying the
|
| 5167 |
indicated operation to the elements of the argument array and selected
|
| 5168 |
elements of the `valarray<T>` object to which the `gslice_array` object
|
| 5169 |
refers.
|
| 5170 |
|
| 5171 |
+
#### Fill function <a id="gslice.array.fill">[[gslice.array.fill]]</a>
|
| 5172 |
|
| 5173 |
``` cpp
|
| 5174 |
void operator=(const T&) const;
|
| 5175 |
```
|
| 5176 |
|
|
|
|
| 5178 |
argument to the elements of the `valarray<T>` object to which the
|
| 5179 |
`gslice_array` object refers.
|
| 5180 |
|
| 5181 |
### Class template `mask_array` <a id="template.mask.array">[[template.mask.array]]</a>
|
| 5182 |
|
| 5183 |
+
#### Overview <a id="template.mask.array.overview">[[template.mask.array.overview]]</a>
|
| 5184 |
|
| 5185 |
``` cpp
|
| 5186 |
namespace std {
|
| 5187 |
template<class T> class mask_array {
|
| 5188 |
public:
|
|
|
|
| 5217 |
```
|
| 5218 |
|
| 5219 |
It has reference semantics to a subset of an array specified by a
|
| 5220 |
boolean mask. Thus, the expression `a[mask] = b;` has the effect of
|
| 5221 |
assigning the elements of `b` to the masked elements in `a` (those for
|
| 5222 |
+
which the corresponding element in `mask` is `true`).
|
| 5223 |
|
| 5224 |
+
#### Assignment <a id="mask.array.assign">[[mask.array.assign]]</a>
|
| 5225 |
|
| 5226 |
``` cpp
|
| 5227 |
void operator=(const valarray<T>&) const;
|
| 5228 |
const mask_array& operator=(const mask_array&) const;
|
| 5229 |
```
|
| 5230 |
|
| 5231 |
These assignment operators have reference semantics, assigning the
|
| 5232 |
values of the argument array elements to selected elements of the
|
| 5233 |
`valarray<T>` object to which it refers.
|
| 5234 |
|
| 5235 |
+
#### Compound assignment <a id="mask.array.comp.assign">[[mask.array.comp.assign]]</a>
|
| 5236 |
|
| 5237 |
``` cpp
|
| 5238 |
void operator*= (const valarray<T>&) const;
|
| 5239 |
void operator/= (const valarray<T>&) const;
|
| 5240 |
void operator%= (const valarray<T>&) const;
|
|
|
|
| 5249 |
|
| 5250 |
These compound assignments have reference semantics, applying the
|
| 5251 |
indicated operation to the elements of the argument array and selected
|
| 5252 |
elements of the `valarray<T>` object to which the mask object refers.
|
| 5253 |
|
| 5254 |
+
#### Fill function <a id="mask.array.fill">[[mask.array.fill]]</a>
|
| 5255 |
|
| 5256 |
``` cpp
|
| 5257 |
void operator=(const T&) const;
|
| 5258 |
```
|
| 5259 |
|
|
|
|
| 5261 |
argument to the elements of the `valarray<T>` object to which the
|
| 5262 |
`mask_array` object refers.
|
| 5263 |
|
| 5264 |
### Class template `indirect_array` <a id="template.indirect.array">[[template.indirect.array]]</a>
|
| 5265 |
|
| 5266 |
+
#### Overview <a id="template.indirect.array.overview">[[template.indirect.array.overview]]</a>
|
| 5267 |
|
| 5268 |
``` cpp
|
| 5269 |
namespace std {
|
| 5270 |
template<class T> class indirect_array {
|
| 5271 |
public:
|
|
|
|
| 5299 |
``` cpp
|
| 5300 |
indirect_array<T> valarray<T>::operator[](const valarray<size_t>&).
|
| 5301 |
```
|
| 5302 |
|
| 5303 |
It has reference semantics to a subset of an array specified by an
|
| 5304 |
+
`indirect_array`. Thus, the expression `a[{}indirect] = b;` has the
|
| 5305 |
+
effect of assigning the elements of `b` to the elements in `a` whose
|
| 5306 |
+
indices appear in `indirect`.
|
| 5307 |
|
| 5308 |
+
#### Assignment <a id="indirect.array.assign">[[indirect.array.assign]]</a>
|
| 5309 |
|
| 5310 |
``` cpp
|
| 5311 |
void operator=(const valarray<T>&) const;
|
| 5312 |
const indirect_array& operator=(const indirect_array&) const;
|
| 5313 |
```
|
|
|
|
| 5331 |
results in undefined behavior since element 4 is specified twice in the
|
| 5332 |
indirection.
|
| 5333 |
|
| 5334 |
— *end example*]
|
| 5335 |
|
| 5336 |
+
#### Compound assignment <a id="indirect.array.comp.assign">[[indirect.array.comp.assign]]</a>
|
| 5337 |
|
| 5338 |
``` cpp
|
| 5339 |
void operator*= (const valarray<T>&) const;
|
| 5340 |
void operator/= (const valarray<T>&) const;
|
| 5341 |
void operator%= (const valarray<T>&) const;
|
|
|
|
| 5354 |
object refers.
|
| 5355 |
|
| 5356 |
If the `indirect_array` specifies an element in the `valarray<T>` object
|
| 5357 |
to which it refers more than once, the behavior is undefined.
|
| 5358 |
|
| 5359 |
+
#### Fill function <a id="indirect.array.fill">[[indirect.array.fill]]</a>
|
| 5360 |
|
| 5361 |
``` cpp
|
| 5362 |
void operator=(const T&) const;
|
| 5363 |
```
|
| 5364 |
|
|
|
|
| 5367 |
`indirect_array` object refers.
|
| 5368 |
|
| 5369 |
### `valarray` range access <a id="valarray.range">[[valarray.range]]</a>
|
| 5370 |
|
| 5371 |
In the `begin` and `end` function templates that follow, *unspecified*1
|
| 5372 |
+
is a type that meets the requirements of a mutable
|
| 5373 |
+
*Cpp17RandomAccessIterator* [[random.access.iterators]] and models
|
| 5374 |
+
`contiguous_iterator` [[iterator.concept.contiguous]], whose
|
| 5375 |
+
`value_type` is the template parameter `T` and whose `reference` type is
|
| 5376 |
+
`T&`. *unspecified*2 is a type that meets the requirements of a constant
|
| 5377 |
+
*Cpp17RandomAccessIterator* and models `contiguous_iterator`, whose
|
| 5378 |
+
`value_type` is the template parameter `T` and whose `reference` type is
|
| 5379 |
+
`const T&`.
|
| 5380 |
|
| 5381 |
The iterators returned by `begin` and `end` for an array are guaranteed
|
| 5382 |
+
to be valid until the member function `resize(size_t, T)`
|
| 5383 |
+
[[valarray.members]] is called for that array or until the lifetime of
|
| 5384 |
that array ends, whichever happens first.
|
| 5385 |
|
| 5386 |
``` cpp
|
| 5387 |
template<class T> unspecified{1} begin(valarray<T>& v);
|
| 5388 |
template<class T> unspecified{2} begin(const valarray<T>& v);
|
|
|
|
| 5395 |
template<class T> unspecified{2} end(const valarray<T>& v);
|
| 5396 |
```
|
| 5397 |
|
| 5398 |
*Returns:* An iterator referencing one past the last value in the array.
|
| 5399 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
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|
| 5400 |
## Mathematical functions for floating-point types <a id="c.math">[[c.math]]</a>
|
| 5401 |
|
| 5402 |
### Header `<cmath>` synopsis <a id="cmath.syn">[[cmath.syn]]</a>
|
| 5403 |
|
| 5404 |
``` cpp
|
|
|
|
| 5610 |
float fabsf(float x);
|
| 5611 |
long double fabsl(long double x);
|
| 5612 |
|
| 5613 |
float hypot(float x, float y); // see [library.c]
|
| 5614 |
double hypot(double x, double y);
|
| 5615 |
+
long double hypot(long double x, long double y); // see [library.c]
|
| 5616 |
float hypotf(float x, float y);
|
| 5617 |
long double hypotl(long double x, long double y);
|
| 5618 |
|
| 5619 |
// [c.math.hypot3], three-dimensional hypotenuse
|
| 5620 |
float hypot(float x, float y, float z);
|
|
|
|
| 5779 |
double fma(double x, double y, double z);
|
| 5780 |
long double fma(long double x, long double y, long double z); // see [library.c]
|
| 5781 |
float fmaf(float x, float y, float z);
|
| 5782 |
long double fmal(long double x, long double y, long double z);
|
| 5783 |
|
| 5784 |
+
// [c.math.lerp], linear interpolation
|
| 5785 |
+
constexpr float lerp(float a, float b, float t) noexcept;
|
| 5786 |
+
constexpr double lerp(double a, double b, double t) noexcept;
|
| 5787 |
+
constexpr long double lerp(long double a, long double b, long double t) noexcept;
|
| 5788 |
+
|
| 5789 |
// [c.math.fpclass], classification / comparison functions
|
| 5790 |
int fpclassify(float x);
|
| 5791 |
int fpclassify(double x);
|
| 5792 |
int fpclassify(long double x);
|
| 5793 |
|
| 5794 |
+
bool isfinite(float x);
|
| 5795 |
+
bool isfinite(double x);
|
| 5796 |
+
bool isfinite(long double x);
|
| 5797 |
|
| 5798 |
+
bool isinf(float x);
|
| 5799 |
+
bool isinf(double x);
|
| 5800 |
+
bool isinf(long double x);
|
| 5801 |
|
| 5802 |
+
bool isnan(float x);
|
| 5803 |
+
bool isnan(double x);
|
| 5804 |
+
bool isnan(long double x);
|
| 5805 |
|
| 5806 |
+
bool isnormal(float x);
|
| 5807 |
+
bool isnormal(double x);
|
| 5808 |
+
bool isnormal(long double x);
|
| 5809 |
|
| 5810 |
+
bool signbit(float x);
|
| 5811 |
+
bool signbit(double x);
|
| 5812 |
+
bool signbit(long double x);
|
| 5813 |
|
| 5814 |
+
bool isgreater(float x, float y);
|
| 5815 |
+
bool isgreater(double x, double y);
|
| 5816 |
+
bool isgreater(long double x, long double y);
|
| 5817 |
|
| 5818 |
+
bool isgreaterequal(float x, float y);
|
| 5819 |
+
bool isgreaterequal(double x, double y);
|
| 5820 |
+
bool isgreaterequal(long double x, long double y);
|
| 5821 |
|
| 5822 |
+
bool isless(float x, float y);
|
| 5823 |
+
bool isless(double x, double y);
|
| 5824 |
+
bool isless(long double x, long double y);
|
| 5825 |
|
| 5826 |
+
bool islessequal(float x, float y);
|
| 5827 |
+
bool islessequal(double x, double y);
|
| 5828 |
+
bool islessequal(long double x, long double y);
|
| 5829 |
|
| 5830 |
+
bool islessgreater(float x, float y);
|
| 5831 |
+
bool islessgreater(double x, double y);
|
| 5832 |
+
bool islessgreater(long double x, long double y);
|
| 5833 |
|
| 5834 |
+
bool isunordered(float x, float y);
|
| 5835 |
+
bool isunordered(double x, double y);
|
| 5836 |
+
bool isunordered(long double x, long double y);
|
| 5837 |
|
| 5838 |
// [sf.cmath], mathematical special functions
|
| 5839 |
|
| 5840 |
+
// [sf.cmath.assoc.laguerre], associated Laguerre polynomials
|
| 5841 |
double assoc_laguerre(unsigned n, unsigned m, double x);
|
| 5842 |
float assoc_laguerref(unsigned n, unsigned m, float x);
|
| 5843 |
long double assoc_laguerrel(unsigned n, unsigned m, long double x);
|
| 5844 |
|
| 5845 |
+
// [sf.cmath.assoc.legendre], associated Legendre functions
|
| 5846 |
double assoc_legendre(unsigned l, unsigned m, double x);
|
| 5847 |
float assoc_legendref(unsigned l, unsigned m, float x);
|
| 5848 |
long double assoc_legendrel(unsigned l, unsigned m, long double x);
|
| 5849 |
|
| 5850 |
// [sf.cmath.beta], beta function
|
| 5851 |
double beta(double x, double y);
|
| 5852 |
float betaf(float x, float y);
|
| 5853 |
long double betal(long double x, long double y);
|
| 5854 |
|
| 5855 |
+
// [sf.cmath.comp.ellint.1], complete elliptic integral of the first kind
|
| 5856 |
double comp_ellint_1(double k);
|
| 5857 |
float comp_ellint_1f(float k);
|
| 5858 |
long double comp_ellint_1l(long double k);
|
| 5859 |
|
| 5860 |
+
// [sf.cmath.comp.ellint.2], complete elliptic integral of the second kind
|
| 5861 |
double comp_ellint_2(double k);
|
| 5862 |
float comp_ellint_2f(float k);
|
| 5863 |
long double comp_ellint_2l(long double k);
|
| 5864 |
|
| 5865 |
+
// [sf.cmath.comp.ellint.3], complete elliptic integral of the third kind
|
| 5866 |
double comp_ellint_3(double k, double nu);
|
| 5867 |
float comp_ellint_3f(float k, float nu);
|
| 5868 |
long double comp_ellint_3l(long double k, long double nu);
|
| 5869 |
|
| 5870 |
+
// [sf.cmath.cyl.bessel.i], regular modified cylindrical Bessel functions
|
| 5871 |
double cyl_bessel_i(double nu, double x);
|
| 5872 |
float cyl_bessel_if(float nu, float x);
|
| 5873 |
long double cyl_bessel_il(long double nu, long double x);
|
| 5874 |
|
| 5875 |
+
// [sf.cmath.cyl.bessel.j], cylindrical Bessel functions of the first kind
|
| 5876 |
double cyl_bessel_j(double nu, double x);
|
| 5877 |
float cyl_bessel_jf(float nu, float x);
|
| 5878 |
long double cyl_bessel_jl(long double nu, long double x);
|
| 5879 |
|
| 5880 |
+
// [sf.cmath.cyl.bessel.k], irregular modified cylindrical Bessel functions
|
| 5881 |
double cyl_bessel_k(double nu, double x);
|
| 5882 |
float cyl_bessel_kf(float nu, float x);
|
| 5883 |
long double cyl_bessel_kl(long double nu, long double x);
|
| 5884 |
|
| 5885 |
+
// [sf.cmath.cyl.neumann], cylindrical Neumann functions;
|
| 5886 |
// cylindrical Bessel functions of the second kind
|
| 5887 |
double cyl_neumann(double nu, double x);
|
| 5888 |
float cyl_neumannf(float nu, float x);
|
| 5889 |
long double cyl_neumannl(long double nu, long double x);
|
| 5890 |
|
| 5891 |
+
// [sf.cmath.ellint.1], incomplete elliptic integral of the first kind
|
| 5892 |
double ellint_1(double k, double phi);
|
| 5893 |
float ellint_1f(float k, float phi);
|
| 5894 |
long double ellint_1l(long double k, long double phi);
|
| 5895 |
|
| 5896 |
+
// [sf.cmath.ellint.2], incomplete elliptic integral of the second kind
|
| 5897 |
double ellint_2(double k, double phi);
|
| 5898 |
float ellint_2f(float k, float phi);
|
| 5899 |
long double ellint_2l(long double k, long double phi);
|
| 5900 |
|
| 5901 |
+
// [sf.cmath.ellint.3], incomplete elliptic integral of the third kind
|
| 5902 |
double ellint_3(double k, double nu, double phi);
|
| 5903 |
float ellint_3f(float k, float nu, float phi);
|
| 5904 |
long double ellint_3l(long double k, long double nu, long double phi);
|
| 5905 |
|
| 5906 |
// [sf.cmath.expint], exponential integral
|
|
|
|
| 5921 |
// [sf.cmath.legendre], Legendre polynomials
|
| 5922 |
double legendre(unsigned l, double x);
|
| 5923 |
float legendref(unsigned l, float x);
|
| 5924 |
long double legendrel(unsigned l, long double x);
|
| 5925 |
|
| 5926 |
+
// [sf.cmath.riemann.zeta], Riemann zeta function
|
| 5927 |
double riemann_zeta(double x);
|
| 5928 |
float riemann_zetaf(float x);
|
| 5929 |
long double riemann_zetal(long double x);
|
| 5930 |
|
| 5931 |
+
// [sf.cmath.sph.bessel], spherical Bessel functions of the first kind
|
| 5932 |
double sph_bessel(unsigned n, double x);
|
| 5933 |
float sph_besself(unsigned n, float x);
|
| 5934 |
long double sph_bessell(unsigned n, long double x);
|
| 5935 |
|
| 5936 |
+
// [sf.cmath.sph.legendre], spherical associated Legendre functions
|
| 5937 |
double sph_legendre(unsigned l, unsigned m, double theta);
|
| 5938 |
float sph_legendref(unsigned l, unsigned m, float theta);
|
| 5939 |
long double sph_legendrel(unsigned l, unsigned m, long double theta);
|
| 5940 |
|
| 5941 |
+
// [sf.cmath.sph.neumann], spherical Neumann functions;
|
| 5942 |
+
// spherical Bessel functions of the second kind
|
| 5943 |
double sph_neumann(unsigned n, double x);
|
| 5944 |
float sph_neumannf(unsigned n, float x);
|
| 5945 |
long double sph_neumannl(unsigned n, long double x);
|
| 5946 |
}
|
| 5947 |
```
|
|
|
|
| 5950 |
standard library header `<math.h>`, with the addition of a
|
| 5951 |
three-dimensional hypotenuse function ([[c.math.hypot3]]) and the
|
| 5952 |
mathematical special functions described in [[sf.cmath]].
|
| 5953 |
|
| 5954 |
[*Note 1*: Several functions have additional overloads in this
|
| 5955 |
+
document, but they have the same behavior as in the C standard library
|
| 5956 |
+
[[library.c]]. — *end note*]
|
| 5957 |
|
| 5958 |
For each set of overloaded functions within `<cmath>`, with the
|
| 5959 |
exception of `abs`, there shall be additional overloads sufficient to
|
| 5960 |
ensure:
|
| 5961 |
|
| 5962 |
+
- If any argument of arithmetic type corresponding to a `double`
|
| 5963 |
parameter has type `long double`, then all arguments of arithmetic
|
| 5964 |
+
type [[basic.fundamental]] corresponding to `double` parameters are
|
| 5965 |
+
effectively cast to `long double`.
|
| 5966 |
+
- Otherwise, if any argument of arithmetic type corresponding to a
|
| 5967 |
`double` parameter has type `double` or an integer type, then all
|
| 5968 |
+
arguments of arithmetic type corresponding to `double` parameters are
|
| 5969 |
+
effectively cast to `double`.
|
| 5970 |
+
- \[*Note 2*: Otherwise, all arguments of arithmetic type corresponding
|
| 5971 |
+
to `double` parameters have type `float`. — *end note*]
|
| 5972 |
|
| 5973 |
+
[*Note 3*: `abs` is exempted from these rules in order to stay
|
| 5974 |
compatible with C. — *end note*]
|
| 5975 |
|
| 5976 |
ISO C 7.12
|
| 5977 |
|
| 5978 |
### Absolute values <a id="c.math.abs">[[c.math.abs]]</a>
|
| 5979 |
|
| 5980 |
+
[*Note 1*: The headers `<cstdlib>` and `<cmath>` declare the functions
|
| 5981 |
+
described in this subclause. — *end note*]
|
|
|
|
| 5982 |
|
| 5983 |
``` cpp
|
| 5984 |
int abs(int j);
|
| 5985 |
long int abs(long int j);
|
| 5986 |
long long int abs(long long int j);
|
|
|
|
| 5993 |
standard library for the functions `abs`, `labs`, `llabs`, `fabsf`,
|
| 5994 |
`fabs`, and `fabsl`.
|
| 5995 |
|
| 5996 |
*Remarks:* If `abs()` is called with an argument of type `X` for which
|
| 5997 |
`is_unsigned_v<X>` is `true` and if `X` cannot be converted to `int` by
|
| 5998 |
+
integral promotion [[conv.prom]], the program is ill-formed.
|
| 5999 |
|
| 6000 |
[*Note 1*: Arguments that can be promoted to `int` are permitted for
|
| 6001 |
compatibility with C. — *end note*]
|
| 6002 |
|
| 6003 |
+
See also: ISO C 7.12.7.2, 7.22.6.1
|
| 6004 |
|
| 6005 |
### Three-dimensional hypotenuse <a id="c.math.hypot3">[[c.math.hypot3]]</a>
|
| 6006 |
|
| 6007 |
``` cpp
|
| 6008 |
float hypot(float x, float y, float z);
|
|
|
|
| 6010 |
long double hypot(long double x, long double y, long double z);
|
| 6011 |
```
|
| 6012 |
|
| 6013 |
*Returns:* $\sqrt{x^2+y^2+z^2}$.
|
| 6014 |
|
| 6015 |
+
### Linear interpolation <a id="c.math.lerp">[[c.math.lerp]]</a>
|
| 6016 |
+
|
| 6017 |
+
``` cpp
|
| 6018 |
+
constexpr float lerp(float a, float b, float t) noexcept;
|
| 6019 |
+
constexpr double lerp(double a, double b, double t) noexcept;
|
| 6020 |
+
constexpr long double lerp(long double a, long double b, long double t) noexcept;
|
| 6021 |
+
```
|
| 6022 |
+
|
| 6023 |
+
*Returns:* a+t(b-a).
|
| 6024 |
+
|
| 6025 |
+
*Remarks:* Let `r` be the value returned. If
|
| 6026 |
+
`isfinite(a) && isfinite(b)`, then:
|
| 6027 |
+
|
| 6028 |
+
- If `t == 0`, then `r == a`.
|
| 6029 |
+
- If `t == 1`, then `r == b`.
|
| 6030 |
+
- If `t >= 0 && t <= 1`, then `isfinite(r)`.
|
| 6031 |
+
- If `isfinite(t) && a == b`, then `r == a`.
|
| 6032 |
+
- If `isfinite(t) || !isnan(t) && b-a != 0`, then `!isnan(r)`.
|
| 6033 |
+
|
| 6034 |
+
Let *`CMP`*`(x,y)` be `1` if `x > y`, `-1` if `x < y`, and `0`
|
| 6035 |
+
otherwise. For any `t1` and `t2`, the product of
|
| 6036 |
+
*`CMP`*`(lerp(a, b, t2), lerp(a, b, t1))`, *`CMP`*`(t2, t1)`, and
|
| 6037 |
+
*`CMP`*`(b, a)` is non-negative.
|
| 6038 |
+
|
| 6039 |
### Classification / comparison functions <a id="c.math.fpclass">[[c.math.fpclass]]</a>
|
| 6040 |
|
| 6041 |
The classification / comparison functions behave the same as the C
|
| 6042 |
macros with the corresponding names defined in the C standard library.
|
| 6043 |
Each function is overloaded for the three floating-point types.
|
|
|
|
| 6054 |
- the function description’s *Returns:* clause explicitly specifies a
|
| 6055 |
domain and those argument values fall outside the specified domain, or
|
| 6056 |
- the corresponding mathematical function value has a nonzero imaginary
|
| 6057 |
component, or
|
| 6058 |
- the corresponding mathematical function is not mathematically
|
| 6059 |
+
defined.[^13]
|
| 6060 |
|
| 6061 |
Unless otherwise specified, each function is defined for all finite
|
| 6062 |
values, for negative infinity, and for positive infinity.
|
| 6063 |
|
| 6064 |
+
#### Associated Laguerre polynomials <a id="sf.cmath.assoc.laguerre">[[sf.cmath.assoc.laguerre]]</a>
|
| 6065 |
|
| 6066 |
``` cpp
|
| 6067 |
double assoc_laguerre(unsigned n, unsigned m, double x);
|
| 6068 |
float assoc_laguerref(unsigned n, unsigned m, float x);
|
| 6069 |
long double assoc_laguerrel(unsigned n, unsigned m, long double x);
|
| 6070 |
```
|
| 6071 |
|
| 6072 |
*Effects:* These functions compute the associated Laguerre polynomials
|
| 6073 |
of their respective arguments `n`, `m`, and `x`.
|
| 6074 |
|
| 6075 |
+
*Returns:* $$\mathsf{L}_n^m(x) =
|
| 6076 |
+
(-1)^m \frac{\mathsf{d} ^ m}{\mathsf{d}x ^ m} \, \mathsf{L}_{n+m}(x)
|
| 6077 |
+
\text{ ,\quad for $x \ge 0$,}$$ where n is `n`, m is `m`, and x is
|
|
|
|
|
|
|
| 6078 |
`x`.
|
| 6079 |
|
| 6080 |
*Remarks:* The effect of calling each of these functions is
|
| 6081 |
*implementation-defined* if `n >= 128` or if `m >= 128`.
|
| 6082 |
|
| 6083 |
+
#### Associated Legendre functions <a id="sf.cmath.assoc.legendre">[[sf.cmath.assoc.legendre]]</a>
|
| 6084 |
|
| 6085 |
``` cpp
|
| 6086 |
double assoc_legendre(unsigned l, unsigned m, double x);
|
| 6087 |
float assoc_legendref(unsigned l, unsigned m, float x);
|
| 6088 |
long double assoc_legendrel(unsigned l, unsigned m, long double x);
|
| 6089 |
```
|
| 6090 |
|
| 6091 |
*Effects:* These functions compute the associated Legendre functions of
|
| 6092 |
their respective arguments `l`, `m`, and `x`.
|
| 6093 |
|
| 6094 |
+
*Returns:* $$\mathsf{P}_\ell^m(x) = (1 - x^2) ^ {m/2} \:
|
| 6095 |
+
\frac{\mathsf{d} ^ m}{\mathsf{d}x ^ m} \, \mathsf{P}_\ell(x)
|
| 6096 |
+
\text{ ,\quad for $|x| \le 1$,}$$ where l is `l`, m is `m`, and x is
|
|
|
|
|
|
|
|
|
|
|
|
|
| 6097 |
`x`.
|
| 6098 |
|
| 6099 |
*Remarks:* The effect of calling each of these functions is
|
| 6100 |
*implementation-defined* if `l >= 128`.
|
| 6101 |
|
|
|
|
| 6108 |
```
|
| 6109 |
|
| 6110 |
*Effects:* These functions compute the beta function of their respective
|
| 6111 |
arguments `x` and `y`.
|
| 6112 |
|
| 6113 |
+
*Returns:*
|
| 6114 |
+
$$\mathsf{B}(x, y) = \frac{\Gamma(x) \, \Gamma(y)}{\Gamma(x + y)}
|
| 6115 |
+
\text{ ,\quad for $x > 0$,\, $y > 0$,}$$ where x is `x` and y is `y`.
|
|
|
|
|
|
|
|
|
|
| 6116 |
|
| 6117 |
+
#### Complete elliptic integral of the first kind <a id="sf.cmath.comp.ellint.1">[[sf.cmath.comp.ellint.1]]</a>
|
| 6118 |
|
| 6119 |
``` cpp
|
| 6120 |
double comp_ellint_1(double k);
|
| 6121 |
float comp_ellint_1f(float k);
|
| 6122 |
long double comp_ellint_1l(long double k);
|
| 6123 |
```
|
| 6124 |
|
| 6125 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6126 |
first kind of their respective arguments `k`.
|
| 6127 |
|
| 6128 |
+
*Returns:*
|
| 6129 |
+
$$\mathsf{K}(k) = \mathsf{F}(k, \pi / 2) \text{ ,\quad for $|k| \le 1$,}$$
|
| 6130 |
+
where k is `k`.
|
|
|
|
| 6131 |
|
| 6132 |
+
See also [[sf.cmath.ellint.1]].
|
| 6133 |
|
| 6134 |
+
#### Complete elliptic integral of the second kind <a id="sf.cmath.comp.ellint.2">[[sf.cmath.comp.ellint.2]]</a>
|
| 6135 |
|
| 6136 |
``` cpp
|
| 6137 |
double comp_ellint_2(double k);
|
| 6138 |
float comp_ellint_2f(float k);
|
| 6139 |
long double comp_ellint_2l(long double k);
|
| 6140 |
```
|
| 6141 |
|
| 6142 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6143 |
second kind of their respective arguments `k`.
|
| 6144 |
|
| 6145 |
+
*Returns:*
|
| 6146 |
+
$$\mathsf{E}(k) = \mathsf{E}(k, \pi / 2) \text{ ,\quad for $|k| \le 1$,}$$
|
| 6147 |
+
where k is `k`.
|
|
|
|
| 6148 |
|
| 6149 |
+
See also [[sf.cmath.ellint.2]].
|
| 6150 |
|
| 6151 |
+
#### Complete elliptic integral of the third kind <a id="sf.cmath.comp.ellint.3">[[sf.cmath.comp.ellint.3]]</a>
|
| 6152 |
|
| 6153 |
``` cpp
|
| 6154 |
double comp_ellint_3(double k, double nu);
|
| 6155 |
float comp_ellint_3f(float k, float nu);
|
| 6156 |
long double comp_ellint_3l(long double k, long double nu);
|
| 6157 |
```
|
| 6158 |
|
| 6159 |
*Effects:* These functions compute the complete elliptic integral of the
|
| 6160 |
third kind of their respective arguments `k` and `nu`.
|
| 6161 |
|
| 6162 |
+
*Returns:*
|
| 6163 |
+
$$\mathsf{\Pi}(\nu, k) = \mathsf{\Pi}(\nu, k, \pi / 2) \text{ ,\quad for $|k| \le 1$,}$$
|
| 6164 |
+
where k is `k` and $\nu$ is `nu`.
|
| 6165 |
|
| 6166 |
+
See also [[sf.cmath.ellint.3]].
|
| 6167 |
|
| 6168 |
+
#### Regular modified cylindrical Bessel functions <a id="sf.cmath.cyl.bessel.i">[[sf.cmath.cyl.bessel.i]]</a>
|
| 6169 |
|
| 6170 |
``` cpp
|
| 6171 |
double cyl_bessel_i(double nu, double x);
|
| 6172 |
float cyl_bessel_if(float nu, float x);
|
| 6173 |
long double cyl_bessel_il(long double nu, long double x);
|
| 6174 |
```
|
| 6175 |
|
| 6176 |
*Effects:* These functions compute the regular modified cylindrical
|
| 6177 |
Bessel functions of their respective arguments `nu` and `x`.
|
| 6178 |
|
| 6179 |
+
*Returns:* $$\mathsf{I}_\nu(x) =
|
| 6180 |
+
i^{-\nu} \mathsf{J}_\nu(ix) =
|
| 6181 |
+
\sum_{k=0}^\infty \frac{(x/2)^{\nu+2k}}{k! \: \Gamma(\nu+k+1)}
|
| 6182 |
+
\text{ ,\quad for $x \ge 0$,}$$ where $\nu$ is `nu` and x is `x`.
|
|
|
|
|
|
|
|
|
|
| 6183 |
|
| 6184 |
*Remarks:* The effect of calling each of these functions is
|
| 6185 |
*implementation-defined* if `nu >= 128`.
|
| 6186 |
|
| 6187 |
+
See also [[sf.cmath.cyl.bessel.j]].
|
| 6188 |
|
| 6189 |
+
#### Cylindrical Bessel functions of the first kind <a id="sf.cmath.cyl.bessel.j">[[sf.cmath.cyl.bessel.j]]</a>
|
| 6190 |
|
| 6191 |
``` cpp
|
| 6192 |
double cyl_bessel_j(double nu, double x);
|
| 6193 |
float cyl_bessel_jf(float nu, float x);
|
| 6194 |
long double cyl_bessel_jl(long double nu, long double x);
|
| 6195 |
```
|
| 6196 |
|
| 6197 |
*Effects:* These functions compute the cylindrical Bessel functions of
|
| 6198 |
the first kind of their respective arguments `nu` and `x`.
|
| 6199 |
|
| 6200 |
+
*Returns:* $$\mathsf{J}_\nu(x) =
|
| 6201 |
+
\sum_{k=0}^\infty \frac{(-1)^k (x/2)^{\nu+2k}}{k! \: \Gamma(\nu+k+1)}
|
| 6202 |
+
\text{ ,\quad for $x \ge 0$,}$$ where $\nu$ is `nu` and x is `x`.
|
|
|
|
|
|
|
| 6203 |
|
| 6204 |
*Remarks:* The effect of calling each of these functions is
|
| 6205 |
*implementation-defined* if `nu >= 128`.
|
| 6206 |
|
| 6207 |
+
#### Irregular modified cylindrical Bessel functions <a id="sf.cmath.cyl.bessel.k">[[sf.cmath.cyl.bessel.k]]</a>
|
| 6208 |
|
| 6209 |
``` cpp
|
| 6210 |
double cyl_bessel_k(double nu, double x);
|
| 6211 |
float cyl_bessel_kf(float nu, float x);
|
| 6212 |
long double cyl_bessel_kl(long double nu, long double x);
|
|
|
|
| 6239 |
\right.$$ where $\nu$ is `nu` and x is `x`.
|
| 6240 |
|
| 6241 |
*Remarks:* The effect of calling each of these functions is
|
| 6242 |
*implementation-defined* if `nu >= 128`.
|
| 6243 |
|
| 6244 |
+
See also [[sf.cmath.cyl.bessel.i]], [[sf.cmath.cyl.bessel.j]],
|
| 6245 |
+
[[sf.cmath.cyl.neumann]].
|
| 6246 |
|
| 6247 |
+
#### Cylindrical Neumann functions <a id="sf.cmath.cyl.neumann">[[sf.cmath.cyl.neumann]]</a>
|
| 6248 |
|
| 6249 |
``` cpp
|
| 6250 |
double cyl_neumann(double nu, double x);
|
| 6251 |
float cyl_neumannf(float nu, float x);
|
| 6252 |
long double cyl_neumannl(long double nu, long double x);
|
|
|
|
| 6274 |
\right.$$ where $\nu$ is `nu` and x is `x`.
|
| 6275 |
|
| 6276 |
*Remarks:* The effect of calling each of these functions is
|
| 6277 |
*implementation-defined* if `nu >= 128`.
|
| 6278 |
|
| 6279 |
+
See also [[sf.cmath.cyl.bessel.j]].
|
| 6280 |
|
| 6281 |
+
#### Incomplete elliptic integral of the first kind <a id="sf.cmath.ellint.1">[[sf.cmath.ellint.1]]</a>
|
| 6282 |
|
| 6283 |
``` cpp
|
| 6284 |
double ellint_1(double k, double phi);
|
| 6285 |
float ellint_1f(float k, float phi);
|
| 6286 |
long double ellint_1l(long double k, long double phi);
|
|
|
|
| 6288 |
|
| 6289 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6290 |
the first kind of their respective arguments `k` and `phi` (`phi`
|
| 6291 |
measured in radians).
|
| 6292 |
|
| 6293 |
+
*Returns:* $$\mathsf{F}(k, \phi) =
|
| 6294 |
+
\int_0^\phi \! \frac{\mathsf{d}\theta}{\sqrt{1 - k^2 \sin^2 \theta}}
|
| 6295 |
+
\text{ ,\quad for $|k| \le 1$,}$$ where k is `k` and φ is `phi`.
|
|
|
|
|
|
|
| 6296 |
|
| 6297 |
+
#### Incomplete elliptic integral of the second kind <a id="sf.cmath.ellint.2">[[sf.cmath.ellint.2]]</a>
|
| 6298 |
|
| 6299 |
``` cpp
|
| 6300 |
double ellint_2(double k, double phi);
|
| 6301 |
float ellint_2f(float k, float phi);
|
| 6302 |
long double ellint_2l(long double k, long double phi);
|
|
|
|
| 6304 |
|
| 6305 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6306 |
the second kind of their respective arguments `k` and `phi` (`phi`
|
| 6307 |
measured in radians).
|
| 6308 |
|
| 6309 |
+
*Returns:*
|
| 6310 |
+
$$\mathsf{E}(k, \phi) = \int_0^\phi \! \sqrt{1 - k^2 \sin^2 \theta} \, \mathsf{d}\theta
|
| 6311 |
+
\text{ ,\quad for $|k| \le 1$,}$$ where k is `k` and φ is `phi`.
|
|
|
|
| 6312 |
|
| 6313 |
+
#### Incomplete elliptic integral of the third kind <a id="sf.cmath.ellint.3">[[sf.cmath.ellint.3]]</a>
|
| 6314 |
|
| 6315 |
``` cpp
|
| 6316 |
double ellint_3(double k, double nu, double phi);
|
| 6317 |
float ellint_3f(float k, float nu, float phi);
|
| 6318 |
long double ellint_3l(long double k, long double nu, long double phi);
|
|
|
|
| 6320 |
|
| 6321 |
*Effects:* These functions compute the incomplete elliptic integral of
|
| 6322 |
the third kind of their respective arguments `k`, `nu`, and `phi` (`phi`
|
| 6323 |
measured in radians).
|
| 6324 |
|
| 6325 |
+
*Returns:* $$\mathsf{\Pi}(\nu, k, \phi) = \int_0^\phi \!
|
| 6326 |
+
\frac{ \mathsf{d}\theta }{ (1 - \nu \, \sin^2 \theta) \sqrt{1 - k^2 \sin^2 \theta} } \text{ ,\quad for $|k| \le 1$,}$$
|
| 6327 |
+
where $\nu$ is `nu`, k is `k`, and φ is `phi`.
|
|
|
|
|
|
|
|
|
|
| 6328 |
|
| 6329 |
#### Exponential integral <a id="sf.cmath.expint">[[sf.cmath.expint]]</a>
|
| 6330 |
|
| 6331 |
``` cpp
|
| 6332 |
double expint(double x);
|
|
|
|
| 6372 |
```
|
| 6373 |
|
| 6374 |
*Effects:* These functions compute the Laguerre polynomials of their
|
| 6375 |
respective arguments `n` and `x`.
|
| 6376 |
|
| 6377 |
+
*Returns:* $$\mathsf{L}_n(x) =
|
| 6378 |
+
\frac{e^x}{n!} \frac{\mathsf{d}^n}{\mathsf{d}x^n} \, (x^n e^{-x})
|
| 6379 |
+
\text{ ,\quad for $x \ge 0$,}$$ where n is `n` and x is `x`.
|
|
|
|
|
|
|
| 6380 |
|
| 6381 |
*Remarks:* The effect of calling each of these functions is
|
| 6382 |
*implementation-defined* if `n >= 128`.
|
| 6383 |
|
| 6384 |
#### Legendre polynomials <a id="sf.cmath.legendre">[[sf.cmath.legendre]]</a>
|
|
|
|
| 6390 |
```
|
| 6391 |
|
| 6392 |
*Effects:* These functions compute the Legendre polynomials of their
|
| 6393 |
respective arguments `l` and `x`.
|
| 6394 |
|
| 6395 |
+
*Returns:* $$\mathsf{P}_\ell(x) =
|
| 6396 |
+
\frac{1}{2^\ell \, \ell!}
|
| 6397 |
+
\frac{\mathsf{d}^\ell}{\mathsf{d}x^\ell} \, (x^2 - 1) ^ \ell
|
| 6398 |
+
\text{ ,\quad for $|x| \le 1$,}$$ where l is `l` and x is `x`.
|
|
|
|
|
|
|
|
|
|
| 6399 |
|
| 6400 |
*Remarks:* The effect of calling each of these functions is
|
| 6401 |
*implementation-defined* if `l >= 128`.
|
| 6402 |
|
| 6403 |
+
#### Riemann zeta function <a id="sf.cmath.riemann.zeta">[[sf.cmath.riemann.zeta]]</a>
|
| 6404 |
|
| 6405 |
``` cpp
|
| 6406 |
double riemann_zeta(double x);
|
| 6407 |
float riemann_zetaf(float x);
|
| 6408 |
long double riemann_zetal(long double x);
|
|
|
|
| 6432 |
& \mbox{for $x < 0$}
|
| 6433 |
\end{array}
|
| 6434 |
\right.
|
| 6435 |
\;$$ where x is `x`.
|
| 6436 |
|
| 6437 |
+
#### Spherical Bessel functions of the first kind <a id="sf.cmath.sph.bessel">[[sf.cmath.sph.bessel]]</a>
|
| 6438 |
|
| 6439 |
``` cpp
|
| 6440 |
double sph_bessel(unsigned n, double x);
|
| 6441 |
float sph_besself(unsigned n, float x);
|
| 6442 |
long double sph_bessell(unsigned n, long double x);
|
| 6443 |
```
|
| 6444 |
|
| 6445 |
*Effects:* These functions compute the spherical Bessel functions of the
|
| 6446 |
first kind of their respective arguments `n` and `x`.
|
| 6447 |
|
| 6448 |
+
*Returns:*
|
| 6449 |
+
$$\mathsf{j}_n(x) = (\pi/2x)^{1\!/\!2} \mathsf{J}_{n + 1\!/\!2}(x) \text{ ,\quad for $x \ge 0$,}$$
|
| 6450 |
+
where n is `n` and x is `x`.
|
|
|
|
| 6451 |
|
| 6452 |
*Remarks:* The effect of calling each of these functions is
|
| 6453 |
*implementation-defined* if `n >= 128`.
|
| 6454 |
|
| 6455 |
+
See also [[sf.cmath.cyl.bessel.j]].
|
| 6456 |
|
| 6457 |
+
#### Spherical associated Legendre functions <a id="sf.cmath.sph.legendre">[[sf.cmath.sph.legendre]]</a>
|
| 6458 |
|
| 6459 |
``` cpp
|
| 6460 |
double sph_legendre(unsigned l, unsigned m, double theta);
|
| 6461 |
float sph_legendref(unsigned l, unsigned m, float theta);
|
| 6462 |
long double sph_legendrel(unsigned l, unsigned m, long double theta);
|
|
|
|
| 6464 |
|
| 6465 |
*Effects:* These functions compute the spherical associated Legendre
|
| 6466 |
functions of their respective arguments `l`, `m`, and `theta` (`theta`
|
| 6467 |
measured in radians).
|
| 6468 |
|
| 6469 |
+
*Returns:* $$\mathsf{Y}_\ell^m(\theta, 0)$$ where
|
| 6470 |
+
$$\mathsf{Y}_\ell^m(\theta, \phi) =
|
| 6471 |
+
(-1)^m \left[\frac{(2 \ell + 1)}{4 \pi} \frac{(\ell - m)!}{(\ell + m)!}\right]^{1/2}
|
| 6472 |
+
\mathsf{P}_\ell^m (\cos\theta) e^{i m \phi}
|
| 6473 |
+
\text{ ,\quad for $|m| \le \ell$,}$$ and l is `l`, m is `m`, and θ
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| 6474 |
is `theta`.
|
| 6475 |
|
| 6476 |
*Remarks:* The effect of calling each of these functions is
|
| 6477 |
*implementation-defined* if `l >= 128`.
|
| 6478 |
|
| 6479 |
+
See also [[sf.cmath.assoc.legendre]].
|
| 6480 |
|
| 6481 |
+
#### Spherical Neumann functions <a id="sf.cmath.sph.neumann">[[sf.cmath.sph.neumann]]</a>
|
| 6482 |
|
| 6483 |
``` cpp
|
| 6484 |
double sph_neumann(unsigned n, double x);
|
| 6485 |
float sph_neumannf(unsigned n, float x);
|
| 6486 |
long double sph_neumannl(unsigned n, long double x);
|
|
|
|
| 6488 |
|
| 6489 |
*Effects:* These functions compute the spherical Neumann functions, also
|
| 6490 |
known as the spherical Bessel functions of the second kind, of their
|
| 6491 |
respective arguments `n` and `x`.
|
| 6492 |
|
| 6493 |
+
*Returns:*
|
| 6494 |
+
$$\mathsf{n}_n(x) = (\pi/2x)^{1\!/\!2} \mathsf{N}_{n + 1\!/\!2}(x)
|
| 6495 |
+
\text{ ,\quad for $x \ge 0$,}$$ where n is `n` and x is `x`.
|
|
|
|
| 6496 |
|
| 6497 |
*Remarks:* The effect of calling each of these functions is
|
| 6498 |
*implementation-defined* if `n >= 128`.
|
| 6499 |
|
| 6500 |
+
See also [[sf.cmath.cyl.neumann]].
|
| 6501 |
+
|
| 6502 |
+
## Numbers <a id="numbers">[[numbers]]</a>
|
| 6503 |
+
|
| 6504 |
+
### Header `<numbers>` synopsis <a id="numbers.syn">[[numbers.syn]]</a>
|
| 6505 |
+
|
| 6506 |
+
``` cpp
|
| 6507 |
+
namespace std::numbers {
|
| 6508 |
+
template<class T> inline constexpr T e_v = unspecified;
|
| 6509 |
+
template<class T> inline constexpr T log2e_v = unspecified;
|
| 6510 |
+
template<class T> inline constexpr T log10e_v = unspecified;
|
| 6511 |
+
template<class T> inline constexpr T pi_v = unspecified;
|
| 6512 |
+
template<class T> inline constexpr T inv_pi_v = unspecified;
|
| 6513 |
+
template<class T> inline constexpr T inv_sqrtpi_v = unspecified;
|
| 6514 |
+
template<class T> inline constexpr T ln2_v = unspecified;
|
| 6515 |
+
template<class T> inline constexpr T ln10_v = unspecified;
|
| 6516 |
+
template<class T> inline constexpr T sqrt2_v = unspecified;
|
| 6517 |
+
template<class T> inline constexpr T sqrt3_v = unspecified;
|
| 6518 |
+
template<class T> inline constexpr T inv_sqrt3_v = unspecified;
|
| 6519 |
+
template<class T> inline constexpr T egamma_v = unspecified;
|
| 6520 |
+
template<class T> inline constexpr T phi_v = unspecified;
|
| 6521 |
+
|
| 6522 |
+
template<floating_point T> inline constexpr T e_v<T> = see below;
|
| 6523 |
+
template<floating_point T> inline constexpr T log2e_v<T> = see below;
|
| 6524 |
+
template<floating_point T> inline constexpr T log10e_v<T> = see below;
|
| 6525 |
+
template<floating_point T> inline constexpr T pi_v<T> = see below;
|
| 6526 |
+
template<floating_point T> inline constexpr T inv_pi_v<T> = see below;
|
| 6527 |
+
template<floating_point T> inline constexpr T inv_sqrtpi_v<T> = see below;
|
| 6528 |
+
template<floating_point T> inline constexpr T ln2_v<T> = see below;
|
| 6529 |
+
template<floating_point T> inline constexpr T ln10_v<T> = see below;
|
| 6530 |
+
template<floating_point T> inline constexpr T sqrt2_v<T> = see below;
|
| 6531 |
+
template<floating_point T> inline constexpr T sqrt3_v<T> = see below;
|
| 6532 |
+
template<floating_point T> inline constexpr T inv_sqrt3_v<T> = see below;
|
| 6533 |
+
template<floating_point T> inline constexpr T egamma_v<T> = see below;
|
| 6534 |
+
template<floating_point T> inline constexpr T phi_v<T> = see below;
|
| 6535 |
+
|
| 6536 |
+
inline constexpr double e = e_v<double>;
|
| 6537 |
+
inline constexpr double log2e = log2e_v<double>;
|
| 6538 |
+
inline constexpr double log10e = log10e_v<double>;
|
| 6539 |
+
inline constexpr double pi = pi_v<double>;
|
| 6540 |
+
inline constexpr double inv_pi = inv_pi_v<double>;
|
| 6541 |
+
inline constexpr double inv_sqrtpi = inv_sqrtpi_v<double>;
|
| 6542 |
+
inline constexpr double ln2 = ln2_v<double>;
|
| 6543 |
+
inline constexpr double ln10 = ln10_v<double>;
|
| 6544 |
+
inline constexpr double sqrt2 = sqrt2_v<double>;
|
| 6545 |
+
inline constexpr double sqrt3 = sqrt3_v<double>;
|
| 6546 |
+
inline constexpr double inv_sqrt3 = inv_sqrt3_v<double>;
|
| 6547 |
+
inline constexpr double egamma = egamma_v<double>;
|
| 6548 |
+
inline constexpr double phi = phi_v<double>;
|
| 6549 |
+
}
|
| 6550 |
+
```
|
| 6551 |
+
|
| 6552 |
+
### Mathematical constants <a id="math.constants">[[math.constants]]</a>
|
| 6553 |
+
|
| 6554 |
+
The library-defined partial specializations of mathematical constant
|
| 6555 |
+
variable templates are initialized with the nearest representable values
|
| 6556 |
+
of e, log₂ e, log₁₀ e, π, $\frac{1}{\pi}$, $\frac{1}{\sqrt{\pi}}$,
|
| 6557 |
+
$\ln 2$, $\ln 10$, $\sqrt{2}$, $\sqrt{3}$, $\frac{1}{\sqrt{3}}$, the
|
| 6558 |
+
Euler-Mascheroni γ constant, and the golden ratio φ constant
|
| 6559 |
+
$\frac{1+\sqrt{5}}{2}$, respectively.
|
| 6560 |
+
|
| 6561 |
+
Pursuant to [[namespace.std]], a program may partially or explicitly
|
| 6562 |
+
specialize a mathematical constant variable template provided that the
|
| 6563 |
+
specialization depends on a program-defined type.
|
| 6564 |
+
|
| 6565 |
+
A program that instantiates a primary template of a mathematical
|
| 6566 |
+
constant variable template is ill-formed.
|
| 6567 |
|
| 6568 |
<!-- Link reference definitions -->
|
| 6569 |
+
[bad.alloc]: support.md#bad.alloc
|
|
|
|
|
|
|
|
|
|
| 6570 |
[basic.fundamental]: basic.md#basic.fundamental
|
| 6571 |
[basic.stc.thread]: basic.md#basic.stc.thread
|
| 6572 |
[basic.types]: basic.md#basic.types
|
| 6573 |
+
[bit]: #bit
|
| 6574 |
+
[bit.cast]: #bit.cast
|
| 6575 |
+
[bit.count]: #bit.count
|
| 6576 |
+
[bit.endian]: #bit.endian
|
| 6577 |
+
[bit.general]: #bit.general
|
| 6578 |
+
[bit.pow.two]: #bit.pow.two
|
| 6579 |
+
[bit.rotate]: #bit.rotate
|
| 6580 |
+
[bit.syn]: #bit.syn
|
| 6581 |
[c.math]: #c.math
|
| 6582 |
[c.math.abs]: #c.math.abs
|
| 6583 |
[c.math.fpclass]: #c.math.fpclass
|
| 6584 |
[c.math.hypot3]: #c.math.hypot3
|
| 6585 |
+
[c.math.lerp]: #c.math.lerp
|
| 6586 |
[c.math.rand]: #c.math.rand
|
| 6587 |
[cfenv]: #cfenv
|
| 6588 |
[cfenv.syn]: #cfenv.syn
|
| 6589 |
[class.gslice]: #class.gslice
|
| 6590 |
[class.gslice.overview]: #class.gslice.overview
|
|
|
|
| 6601 |
[complex.special]: #complex.special
|
| 6602 |
[complex.syn]: #complex.syn
|
| 6603 |
[complex.transcendentals]: #complex.transcendentals
|
| 6604 |
[complex.value.ops]: #complex.value.ops
|
| 6605 |
[cons.slice]: #cons.slice
|
| 6606 |
+
[conv.prom]: expr.md#conv.prom
|
| 6607 |
[cpp.pragma]: cpp.md#cpp.pragma
|
| 6608 |
+
[cpp17.copyassignable]: #cpp17.copyassignable
|
| 6609 |
+
[cpp17.copyconstructible]: #cpp17.copyconstructible
|
| 6610 |
+
[cpp17.equalitycomparable]: #cpp17.equalitycomparable
|
| 6611 |
[dcl.init]: dcl.md#dcl.init
|
| 6612 |
+
[expr.const]: expr.md#expr.const
|
|
|
|
| 6613 |
[gslice.access]: #gslice.access
|
| 6614 |
[gslice.array.assign]: #gslice.array.assign
|
| 6615 |
[gslice.array.comp.assign]: #gslice.array.comp.assign
|
| 6616 |
[gslice.array.fill]: #gslice.array.fill
|
| 6617 |
[gslice.cons]: #gslice.cons
|
| 6618 |
[implimits]: limits.md#implimits
|
|
|
|
| 6619 |
[indirect.array.assign]: #indirect.array.assign
|
| 6620 |
[indirect.array.comp.assign]: #indirect.array.comp.assign
|
| 6621 |
[indirect.array.fill]: #indirect.array.fill
|
|
|
|
| 6622 |
[input.iterators]: iterators.md#input.iterators
|
| 6623 |
[input.output]: input.md#input.output
|
| 6624 |
+
[intro.object]: basic.md#intro.object
|
| 6625 |
[iostate.flags]: input.md#iostate.flags
|
| 6626 |
[istream.formatted]: input.md#istream.formatted
|
| 6627 |
+
[iterator.concept.contiguous]: iterators.md#iterator.concept.contiguous
|
| 6628 |
[iterator.requirements.general]: iterators.md#iterator.requirements.general
|
| 6629 |
[library.c]: library.md#library.c
|
| 6630 |
[mask.array.assign]: #mask.array.assign
|
| 6631 |
[mask.array.comp.assign]: #mask.array.comp.assign
|
| 6632 |
[mask.array.fill]: #mask.array.fill
|
| 6633 |
+
[math.constants]: #math.constants
|
| 6634 |
+
[namespace.std]: library.md#namespace.std
|
| 6635 |
[numarray]: #numarray
|
| 6636 |
+
[numbers]: #numbers
|
| 6637 |
+
[numbers.syn]: #numbers.syn
|
|
|
|
|
|
|
|
|
|
| 6638 |
[numeric.requirements]: #numeric.requirements
|
| 6639 |
[numerics]: #numerics
|
|
|
|
| 6640 |
[numerics.general]: #numerics.general
|
| 6641 |
+
[numerics.summary]: #numerics.summary
|
| 6642 |
[output.iterators]: iterators.md#output.iterators
|
|
|
|
| 6643 |
[rand]: #rand
|
| 6644 |
[rand.adapt]: #rand.adapt
|
| 6645 |
[rand.adapt.disc]: #rand.adapt.disc
|
| 6646 |
[rand.adapt.general]: #rand.adapt.general
|
| 6647 |
[rand.adapt.ibits]: #rand.adapt.ibits
|
|
|
|
| 6689 |
[rand.synopsis]: #rand.synopsis
|
| 6690 |
[rand.util]: #rand.util
|
| 6691 |
[rand.util.canonical]: #rand.util.canonical
|
| 6692 |
[rand.util.seedseq]: #rand.util.seedseq
|
| 6693 |
[random.access.iterators]: iterators.md#random.access.iterators
|
|
|
|
| 6694 |
[res.on.data.races]: library.md#res.on.data.races
|
| 6695 |
[sf.cmath]: #sf.cmath
|
| 6696 |
+
[sf.cmath.assoc.laguerre]: #sf.cmath.assoc.laguerre
|
| 6697 |
+
[sf.cmath.assoc.legendre]: #sf.cmath.assoc.legendre
|
| 6698 |
[sf.cmath.beta]: #sf.cmath.beta
|
| 6699 |
+
[sf.cmath.comp.ellint.1]: #sf.cmath.comp.ellint.1
|
| 6700 |
+
[sf.cmath.comp.ellint.2]: #sf.cmath.comp.ellint.2
|
| 6701 |
+
[sf.cmath.comp.ellint.3]: #sf.cmath.comp.ellint.3
|
| 6702 |
+
[sf.cmath.cyl.bessel.i]: #sf.cmath.cyl.bessel.i
|
| 6703 |
+
[sf.cmath.cyl.bessel.j]: #sf.cmath.cyl.bessel.j
|
| 6704 |
+
[sf.cmath.cyl.bessel.k]: #sf.cmath.cyl.bessel.k
|
| 6705 |
+
[sf.cmath.cyl.neumann]: #sf.cmath.cyl.neumann
|
| 6706 |
+
[sf.cmath.ellint.1]: #sf.cmath.ellint.1
|
| 6707 |
+
[sf.cmath.ellint.2]: #sf.cmath.ellint.2
|
| 6708 |
+
[sf.cmath.ellint.3]: #sf.cmath.ellint.3
|
| 6709 |
[sf.cmath.expint]: #sf.cmath.expint
|
| 6710 |
[sf.cmath.hermite]: #sf.cmath.hermite
|
| 6711 |
[sf.cmath.laguerre]: #sf.cmath.laguerre
|
| 6712 |
[sf.cmath.legendre]: #sf.cmath.legendre
|
| 6713 |
+
[sf.cmath.riemann.zeta]: #sf.cmath.riemann.zeta
|
| 6714 |
+
[sf.cmath.sph.bessel]: #sf.cmath.sph.bessel
|
| 6715 |
+
[sf.cmath.sph.legendre]: #sf.cmath.sph.legendre
|
| 6716 |
+
[sf.cmath.sph.neumann]: #sf.cmath.sph.neumann
|
| 6717 |
[slice.access]: #slice.access
|
| 6718 |
[slice.arr.assign]: #slice.arr.assign
|
| 6719 |
[slice.arr.comp.assign]: #slice.arr.comp.assign
|
| 6720 |
[slice.arr.fill]: #slice.arr.fill
|
| 6721 |
+
[slice.ops]: #slice.ops
|
| 6722 |
[strings]: strings.md#strings
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| 6723 |
[template.gslice.array]: #template.gslice.array
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| 6724 |
[template.gslice.array.overview]: #template.gslice.array.overview
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| 6725 |
[template.indirect.array]: #template.indirect.array
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| 6726 |
[template.indirect.array.overview]: #template.indirect.array.overview
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| 6727 |
[template.mask.array]: #template.mask.array
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| 6728 |
[template.mask.array.overview]: #template.mask.array.overview
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| 6729 |
[template.slice.array]: #template.slice.array
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| 6730 |
[template.slice.array.overview]: #template.slice.array.overview
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| 6731 |
[template.valarray]: #template.valarray
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| 6732 |
[template.valarray.overview]: #template.valarray.overview
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| 6733 |
+
[thread.jthread.class]: thread.md#thread.jthread.class
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| 6734 |
[thread.thread.class]: thread.md#thread.thread.class
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| 6735 |
+
[utility.arg.requirements]: library.md#utility.arg.requirements
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| 6736 |
[valarray.access]: #valarray.access
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| 6737 |
[valarray.assign]: #valarray.assign
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| 6738 |
[valarray.binary]: #valarray.binary
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| 6739 |
[valarray.cassign]: #valarray.cassign
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| 6740 |
[valarray.comparison]: #valarray.comparison
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| 6745 |
[valarray.special]: #valarray.special
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| 6746 |
[valarray.sub]: #valarray.sub
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| 6747 |
[valarray.syn]: #valarray.syn
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| 6748 |
[valarray.transcend]: #valarray.transcend
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| 6749 |
[valarray.unary]: #valarray.unary
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| 6750 |
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| 6751 |
[^1]: In other words, value types. These include arithmetic types,
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| 6752 |
pointers, the library class `complex`, and instantiations of
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| 6753 |
`valarray` for value types.
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| 6754 |
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| 6769 |
[^6]: The distribution corresponding to this probability density
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| 6770 |
function is also known (with a possible change of variable) as the
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| 6771 |
Gumbel Type I, the log-Weibull, or the Fisher-Tippett Type I
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| 6772 |
distribution.
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| 6773 |
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| 6774 |
+
[^7]: [[implimits]] recommends a minimum number of recursively nested
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| 6775 |
+
template instantiations. This requirement thus indirectly suggests a
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| 6776 |
+
minimum allowable complexity for valarray expressions.
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| 6777 |
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| 6778 |
[^8]: The intent is to specify an array template that has the minimum
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| 6779 |
functionality necessary to address aliasing ambiguities and the
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| 6780 |
+
proliferation of temporary objects. Thus, the `valarray` template is
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| 6781 |
neither a matrix class nor a field class. However, it is a very
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| 6782 |
useful building block for designing such classes.
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| 6783 |
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| 6784 |
[^9]: This default constructor is essential, since arrays of `valarray`
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| 6785 |
may be useful. After initialization, the length of an empty array
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| 6788 |
[^10]: This constructor is the preferred method for converting a C array
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| 6789 |
to a `valarray` object.
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| 6790 |
|
| 6791 |
[^11]: This copy constructor creates a distinct array rather than an
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| 6792 |
alias. Implementations in which arrays share storage are permitted,
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| 6793 |
+
but they would need to implement a copy-on-reference mechanism to
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| 6794 |
+
ensure that arrays are conceptually distinct.
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| 6795 |
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| 6796 |
[^12]: BLAS stands for *Basic Linear Algebra Subprograms.* C++ programs
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| 6797 |
may instantiate this class. See, for example, Dongarra, Du Croz,
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| 6798 |
Duff, and Hammerling: *A set of Level 3 Basic Linear Algebra
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| 6799 |
Subprograms*; Technical Report MCS-P1-0888, Argonne National
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| 6800 |
Laboratory (USA), Mathematics and Computer Science Division, August,
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| 6801 |
1988.
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| 6802 |
|
| 6803 |
+
[^13]: A mathematical function is mathematically defined for a given set
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| 6804 |
of argument values (a) if it is explicitly defined for that set of
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| 6805 |
argument values, or (b) if its limiting value exists and does not
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| 6806 |
depend on the direction of approach.
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