From Jason Turner

[linalg.algs.blas2.rank2]

Diff to HTML by rtfpessoa

Files changed (1) hide show
  1. tmp/tmp7d8b__8r/{from.md → to.md} +59 -0
tmp/tmp7d8b__8r/{from.md → to.md} RENAMED
@@ -0,0 +1,59 @@
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
+ #### Symmetric and Hermitian rank-2 matrix updates <a id="linalg.algs.blas2.rank2">[[linalg.algs.blas2.rank2]]</a>
2
+
3
+ [*Note 1*: These functions correspond to the BLAS functions
4
+ `xSYR2`,`xSPR2`, `xHER2` and `xHPR2`. — *end note*]
5
+
6
+ The following elements apply to all functions in
7
+ [[linalg.algs.blas2.rank2]].
8
+
9
+ *Mandates:*
10
+
11
+ - If `InOutMat` has `layout_blas_packed` layout, then the layout’s
12
+ `Triangle` template argument has the same type as the function’s
13
+ `Triangle` template argument;
14
+ - `compatible-static-extents<decltype(A), decltype(A)>(0, 1)` is `true`;
15
+ and
16
+ - `possibly-multipliable<decltype(A), decltype(x), decltype(y)>()` is
17
+ `true`.
18
+
19
+ *Preconditions:*
20
+
21
+ - `A.extent(0)` equals `A.extent(1)`, and
22
+ - `multipliable(A, x, y)` is `true`.
23
+
24
+ *Complexity:* 𝑂(`x.extent(0)` × `y.extent(0)`).
25
+
26
+ ``` cpp
27
+ template<in-vector InVec1, in-vector InVec2,
28
+ possibly-packed-inout-matrix InOutMat, class Triangle>
29
+ void symmetric_matrix_rank_2_update(InVec1 x, InVec2 y, InOutMat A, Triangle t);
30
+ template<class ExecutionPolicy, in-vector InVec1, in-vector InVec2,
31
+ possibly-packed-inout-matrix InOutMat, class Triangle>
32
+ void symmetric_matrix_rank_2_update(ExecutionPolicy&& exec,
33
+ InVec1 x, InVec2 y, InOutMat A, Triangle t);
34
+ ```
35
+
36
+ These functions perform a symmetric rank-2 update of the symmetric
37
+ matrix `A`, taking into account the `Triangle` parameter that applies to
38
+ `A` [[linalg.general]].
39
+
40
+ *Effects:* Computes A' such that $A' = A + x y^T + y x^T$ and assigns
41
+ each element of A' to the corresponding element of A.
42
+
43
+ ``` cpp
44
+ template<in-vector InVec1, in-vector InVec2,
45
+ possibly-packed-inout-matrix InOutMat, class Triangle>
46
+ void hermitian_matrix_rank_2_update(InVec1 x, InVec2 y, InOutMat A, Triangle t);
47
+ template<class ExecutionPolicy, in-vector InVec1, in-vector InVec2,
48
+ possibly-packed-inout-matrix InOutMat, class Triangle>
49
+ void hermitian_matrix_rank_2_update(ExecutionPolicy&& exec,
50
+ InVec1 x, InVec2 y, InOutMat A, Triangle t);
51
+ ```
52
+
53
+ These functions perform a Hermitian rank-2 update of the Hermitian
54
+ matrix `A`, taking into account the `Triangle` parameter that applies to
55
+ `A` [[linalg.general]].
56
+
57
+ *Effects:* Computes A' such that $A' = A + x y^H + y x^H$ and assigns
58
+ each element of A' to the corresponding element of A.
59
+