LinearAlgebra`BLAS`
LinearAlgebra`BLAS`

# GEMV

GEMV[ts,α,a,x,β,y]

computes the matrix-vector multiplication α opts[a].x +β y and resets y to the result.

# Details

• To use GEMV, you first need to load the BLAS Package using Needs["LinearAlgebra`BLAS`"].
• The following arguments must be given:
•  ts input string transposition string α input expression scalar mutliple a input expression rectangular matrix x input expression vector β input expression scalar multiple y input/output symbol vector; the symbol value is modified in place
• The transposition string ts describes the operator opts and may be specified as:
•  "N" no transposition "T" transpose "C" conjugate transpose
• Dimensions of the matrix and vector arguments must be such that the dot product and addition are well defined.

# Examples

open allclose all

## Basic Examples(1)

Compute a.x+2 y and save it in y:

## Scope(4)

Real matrix and vectors:

Complex matrix and vectors:

Arbitrary-precision matrix and vectors:

Symbolic matrix and vectors:

## Properties & Relations(3)

GEMV["N",α,a,x,β,y] is equivalent to y=α a.x+β y:

GEMV["T",α,a,x,β,y] is equivalent to y=α Transpose[a].x+β y:

GEMV["C",α,a,x,β,y] is equivalent to y=α ConjugateTranspose[a].x+β y:

## Possible Issues(2)

The last argument must be a symbol: If the last argument is not a symbol initialized to a vector then an error message is issued: 