p?ger

Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

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ID 766686

Date 3/31/2023

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p?ger

Performs a rank-1 update of a distributed general matrix.

Syntax

call psger(m, n, alpha, x, ix, jx, descx, incx, y, iy, jy, descy, incy, a, ia, ja, desca)

call pdger(m, n, alpha, x, ix, jx, descx, incx, y, iy, jy, descy, incy, a, ia, ja, desca)

Include Files

mkl_pblas.h

Description

The p?ger routines perform a distributed matrix-vector operation defined as

sub(A) := alpha*sub(x)*sub(y)' + sub(A),

where:

alpha is a scalar,

sub(A) is a m-by-n distributed general matrix, sub(A)=A(ia:ia+m-1, ja:ja+n-1),

sub(x) is an m-element distributed vector, sub(y) is an n-element distributed vector,

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

m

(global) INTEGER. Specifies the number of rows of the distributed matrix sub(A), m≥0.

n

(global) INTEGER. Specifies the number of columns of the distributed matrix sub(A), n≥0.

alpha

(global)REAL for psger

DOUBLE REAL for pdger

Specifies the scalar alpha.

x

(local)REAL for psger

DOUBLE REAL for pdger

Array, size at least (jx-1)*m_x + ix+(m-1)*abs(incx)).

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

ix, jx

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

incx

(global) INTEGER. 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)REAL for psger

DOUBLE REAL for pdger

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

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

iy, jy

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

incy

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

a

(local)REAL for psger

DOUBLE REAL for pdger

Array, size (lld_a, LOCq(ja+n-1)).

Before entry this array contains the local pieces of the distributed matrix sub(A).

ia, ja

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

desca

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

Output Parameters

a: Overwritten by the updated distributed matrix sub(A).

Parent topic: PBLAS Level 2 Routines

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Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

p?ger