Developer Reference for Intel® oneAPI Math Kernel Library for C

ID 766684
Date 3/22/2024
Public

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Document Table of Contents

p?nrm2

Computes the Euclidean norm of a distributed vector.

Syntax

void psnrm2 (const MKL_INT *n , float *norm2 , const float *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pdnrm2 (const MKL_INT *n , double *norm2 , const double *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pscnrm2 (const MKL_INT *n , float *norm2 , const MKL_Complex8 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

void pdznrm2 (const MKL_INT *n , double *norm2 , const MKL_Complex16 *x , const MKL_INT *ix , const MKL_INT *jx , const MKL_INT *descx , const MKL_INT *incx );

Include Files

  • mkl_pblas.h

Description

The p?nrm2 functions compute the Euclidean norm of a distributed vector sub(x),

where sub(x) is an n-element distributed vector.

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

norm2

(local) and pscnrm2.

Contains the Euclidean norm of a distributed vector only in its scope.