Developer Reference for Intel® oneAPI Math Kernel Library for Fortran

ID 766686
Date 6/24/2024
Public

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?nrm2

Computes the Euclidean norm of a vector.

Syntax

res = snrm2(n, x, incx)

res = dnrm2(n, x, incx)

res = scnrm2(n, x, incx)

res = dznrm2(n, x, incx)

res = nrm2(x)

Include Files

  • mkl.fi, blas.f90

Description

The ?nrm2 routines perform a vector reduction operation defined as

res = ||x||,

where:

x is a vector,

res is a value containing the Euclidean norm of the elements of x.

Input Parameters

n

INTEGER. Specifies the number of elements in vector x.

x

REAL for snrm2

DOUBLE PRECISION for dnrm2

COMPLEX for scnrm2

DOUBLE COMPLEX for dznrm2

Array, size at least (1 + (n -1)*abs (incx)).

incx

INTEGER. Specifies the increment for the elements of x.

Output Parameters

res

REAL for snrm2

DOUBLE PRECISION for dnrm2

REAL for scnrm2

DOUBLE PRECISION for dznrm2

Contains the Euclidean norm of the vector x.

BLAS 95 Interface Notes

Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see BLAS 95 Interface Conventions.

Specific details for the routine nrm2 interface are the following:

x

Holds the vector with the number of elements n.