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mir.glas.l2

Level 2

This is a submodule of mir.glas.

The Level 2 BLAS perform matrix-vector operations.

Note GLAS is singe thread for now.

Matrix-vector operations
Function Name	Description
gemv	general matrix-vector multiplication, partially optimized

License:

Boost License 1.0.

Authors:

Ilya Yaroshenko

nothrow @nogc @system void gemv(A, B, C, SliceKind kindA, SliceKind kindB, SliceKind kindC)(C alpha, Slice!(const(A)*, 2, kindA) asl, Slice!(const(B)*, 1, kindB) xsl, C beta, Slice!(C*, 1, kindC) ysl) if (allSatisfy!(isNumeric, A, B, C));

DRAFT Performs general matrix-vector multiplication.

Pseudo code y := alpha A × x + beta y.

Parameters:

C `alpha`	scalar
Slice!(const(A)*, 2, kindA) `asl`	m ⨉ n matrix
Slice!(const(B)*, 1, kindB) `xsl`	n ⨉ 1 vector
C `beta`	scalar. When `beta` is supplied as zero then the vector `ysl` need not be set on input.
Slice!(C*, 1, kindC) `ysl`	m ⨉ 1 vector

Note GLAS does not require transposition parameters. Use transposed to perform zero cost Slice transposition.

BLAS SGEMV, DGEMV, (CGEMV, ZGEMV are not implemented for now)

Examples:

import mir.ndslice;

auto a = slice!double(3, 5);
a[] =
    [[-5,  1,  7, 7, -4],
     [-1, -5,  6, 3, -3],
     [-5, -2, -3, 6,  0]];

auto b = slice!double(5);
b[] =
    [-5.0,
      4.0,
     -4.0,
     -1.0,
      9.0];

auto c = slice!double(3);

gemv!(double, double, double)(1.0, a, b, 0.0, c);

assert(c ==
    [-42.0,
     -69.0,
      23.0]);

Library Reference

mir.glas.l2

Level 2

Matrix-vector operations