tmp/tmpk4n0z5ik/{from.md → to.md}
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| 1 |
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##### Exposition-only helpers <a id="mdspan.extents.expo">[[mdspan.extents.expo]]</a>
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| 2 |
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| 3 |
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``` cpp
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static constexpr rank_type dynamic-index(rank_type i) noexcept;
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```
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*Preconditions:* `i <= rank()` is `true`.
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*Returns:* The number of Eᵣ with r < `i` for which Eᵣ is a dynamic
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| 10 |
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extent.
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``` cpp
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static constexpr rank_type dynamic-index-inv(rank_type i) noexcept;
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```
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*Preconditions:* `i < rank_dynamic()` is `true`.
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*Returns:* The minimum value of r such that
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*`dynamic-index`*`(`r` + 1) == i + 1` is `true`.
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``` cpp
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constexpr size_t fwd-prod-of-extents(rank_type i) const noexcept;
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```
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*Preconditions:* `i <= rank()` is `true`.
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*Returns:* If `i > 0` is `true`, the product of `extent(`k`)` for all k
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in the range [0, `i`), otherwise `1`.
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``` cpp
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constexpr size_t rev-prod-of-extents(rank_type i) const noexcept;
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```
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*Preconditions:* `i < rank()` is `true`.
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*Returns:* If `i + 1 < rank()` is `true`, the product of `extent(`k`)`
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for all k in the range [`i + 1`, `rank()`), otherwise `1`.
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``` cpp
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template<class OtherIndexType>
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static constexpr auto index-cast(OtherIndexType&& i) noexcept;
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```
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*Effects:*
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| 45 |
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| 46 |
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- If `OtherIndexType` is an integral type other than `bool`, then
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equivalent to `return i;`,
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- otherwise, equivalent to `return static_cast<index_type>(i);`.
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[*Note 1*: This function will always return an integral type other than
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`bool`. Since this function’s call sites are constrained on
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convertibility of `OtherIndexType` to `index_type`, integer-class types
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can use the `static_cast` branch without loss of
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precision. — *end note*]
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