Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 11/07/2023
Public

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p?nrm2

Computes the Euclidean norm of a distributed vector.

Syntax

call psnrm2(n, norm2, x, ix, jx, descx, incx)

call pdnrm2(n, norm2, x, ix, jx, descx, incx)

call pscnrm2(n, norm2, x, ix, jx, descx, incx)

call pdznrm2(n, norm2, x, ix, jx, descx, 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) INTEGER. The length of distributed vector sub(x), n0.

x

(local) REAL for psnrm2

DOUBLE PRECISION for pdnrm2

COMPLEX for pscnrm2

DOUBLE COMPLEX for pdznrm2

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) 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.

Output Parameters

norm2

(local) REAL for psnrm2 and pscnrm2.

DOUBLE PRECISION for pdnrm2 and pdznrm2

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