Computes the sum of magnitudes of elements of a distributed vector.

## Syntax

void psasum (const MKL_INT *n , float *asum , const float *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pdasum (const MKL_INT *n , double *asum , const double *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pscasum (const MKL_INT *n , float *asum , const MKL_Complex8 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pdzasum (const MKL_INT *n , double *asum , const MKL_Complex16 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

• mkl_pblas.h

## Description

The functions p?asum compute the sum of the magnitudes of elements of a distributed vector sub(x),

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

## Input Parameters

n

(global) The length of distributed vector sub(x), n0.

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.

## Output Parameters

asum

(local) and pscasum.

Contains the sum of magnitudes of elements of the distributed vector only in its scope.