p?geru

Performs a rank-1 update (unconjugated) of a distributed general matrix.

Syntax

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

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

Include Files

The C interfaces for this function are specified in the mkl_pblas.h include file.

Description

The p?geru routines perform a 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) COMPLEX for pcgeru

DOUBLE COMPLEX for pzgeru

Specifies the scalar alpha.

x

(local) COMPLEX for pcgeru

DOUBLE COMPLEX for pzgeru

Array, DIMENSION at least (jx-1)*m_x + ix+(n-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 8. 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) COMPLEX for pcgeru

DOUBLE COMPLEX for pzgeru

Array, DIMENSION 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 8. 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) COMPLEX for pcgeru

DOUBLE COMPLEX for pzgeru

Array, DIMENSION at least (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 8. The array descriptor of the distributed matrix A.

Output Parameters

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