Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 12/16/2022
Public

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Document Table of Contents

cblas_?hemv

Computes a matrix-vector product using a Hermitian matrix.

Syntax

void cblas_chemv (const CBLAS_LAYOUT Layout, const CBLAS_UPLO uplo, const MKL_INT n, const void *alpha, const void *a, const MKL_INT lda, const void *x, const MKL_INT incx, const void *beta, void *y, const MKL_INT incy);

void cblas_zhemv (const CBLAS_LAYOUT Layout, const CBLAS_UPLO uplo, const MKL_INT n, const void *alpha, const void *a, const MKL_INT lda, const void *x, const MKL_INT incx, const void *beta, void *y, const MKL_INT incy);

Include Files
  • mkl.h
Description

The ?hemv routines perform a matrix-vector operation defined as

y := alpha*A*x + beta*y,

where:

alpha and beta are scalars,

x and y are n-element vectors,

A is an n-by-n Hermitian matrix.

Input Parameters
Layout

Specifies whether two-dimensional array storage is row-major (CblasRowMajor) or column-major (CblasColMajor).

uplo

Specifies whether the upper or lower triangular part of the array a is used.

If uplo = CblasUpper, then the upper triangular of the array a is used.

If uplo = CblasLower, then the low triangular of the array a is used.

n

Specifies the order of the matrix A. The value of n must be at least zero.

alpha

Specifies the scalar alpha.

a

Array, size lda*n.

Before entry with uplo = CblasUpper, the leading n-by-n upper triangular part of the array a must contain the upper triangular part of the Hermitian matrix and the strictly lower triangular part of a is not referenced. Before entry with uplo = CblasLower, the leading n-by-n lower triangular part of the array a must contain the lower triangular part of the Hermitian matrix and the strictly upper triangular part of a is not referenced.

The imaginary parts of the diagonal elements need not be set and are assumed to be zero.

lda

Specifies the leading dimension of a as declared in the calling (sub)program. The value of lda must be at least max(1, n).

x

Array, size at least (1 + (n - 1)*abs(incx)). Before entry, the incremented array x must contain the n-element vector x.

incx

Specifies the increment for the elements of x.

The value of incx must not be zero.

beta

Specifies the scalar beta. When beta is supplied as zero then y need not be set on input.

y

Array, size at least (1 + (n - 1)*abs(incy)). Before entry, the incremented array y must contain the n-element vector y.

incy

Specifies the increment for the elements of y.

The value of incy must not be zero.

Output Parameters
y

Overwritten by the updated vector y.