p?axpy

Developer Reference for Intel® oneAPI Math Kernel Library for C

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ID 766684

Date 11/07/2023

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p?axpy

Computes a distributed vector-scalar product and adds the result to a distributed vector.

Syntax

void psaxpy (const MKL_INT *n , const float *a , const float *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx , float *y , const MKL_INT *iy , const MKL_INT *jy , const MKL_INT *descy , const MKL_INT *incy );

void pdaxpy (const MKL_INT *n , const double *a , const double *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx , double *y , const MKL_INT *iy , const MKL_INT *jy , const MKL_INT *descy , const MKL_INT *incy );

void pcaxpy (const MKL_INT *n , const MKL_Complex8 *a , const MKL_Complex8 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx , MKL_Complex8 *y , const MKL_INT *iy , const MKL_INT *jy , const MKL_INT *descy , const MKL_INT *incy );

void pzaxpy (const MKL_INT *n , const MKL_Complex16 *a , const MKL_Complex16 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx , MKL_Complex16 *y , const MKL_INT *iy , const MKL_INT *jy , const MKL_INT *descy , const MKL_INT *incy );

Include Files

mkl_pblas.h

Description

The p?axpy routines perform the following operation with distributed vectors:

sub(y) := sub(y) + a*sub(x)

where:

a is a scalar;

sub(x) and sub(y) are n-element distributed vectors.

sub(x) denotes X(ix, jx:jx+n-1) if incx=m_x, and X(ix: ix+n-1, jx) if incx= 1;

sub(y) denotes Y(iy, jy:jy+n-1) if incy=m_y, and Y(iy: iy+n-1, jy) if incy= 1.

Input Parameters

n

(global) The length of distributed vectors, n≥0.

a

(local)

Specifies the scalar a.

x

(local)

Array, size (jx-1)*m_x + ix+(n-1)*abs(incx)).

This array contains the entries of the distributed vector sub(x).

ix, jx

(global) The row and column indices in the distributed matrix X indicating the first row and the first column of the submatrix sub(X), respectively.

descx

(global and local) array of dimension 9. The array descriptor of the distributed matrix X.

incx

(global) Specifies the increment for the elements of sub(x). Only two values are supported, namely 1 and m_x. incx must not be zero.

y

(local)

Array, size (jy-1)*m_y + iy+(n-1)*abs(incy)).

This array contains the entries of the distributed vector sub(y).

iy, jy

(global) The row and column indices in the distributed matrix Y indicating the first row and the first column of the submatrix sub(Y), respectively.

descy

(global and local) array of dimension 9. The array descriptor of the distributed matrix Y.

incy

(global) Specifies the increment for the elements of sub(y). Only two values are supported, namely 1 and m_y. incy must not be zero.

Output Parameters

y: Overwritten by sub(y) := sub(y) + a*sub(x).

Parent topic: PBLAS Level 1 Routines

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Developer Reference for Intel® oneAPI Math Kernel Library for C

p?axpy

Syntax

Include Files

Description

Input Parameters

Output Parameters