BLAS/SRC/dnrm2.f90(3) | Library Functions Manual | BLAS/SRC/dnrm2.f90(3) |
NAME
BLAS/SRC/dnrm2.f90
SYNOPSIS
Functions/Subroutines
real(wp) function dnrm2 (n, x, incx)
DNRM2
Function/Subroutine Documentation
real(wp) function dnrm2 (integer n, real(wp), dimension(*) x, integer incx)
DNRM2
Purpose:
DNRM2 returns the euclidean norm of a vector via the function name, so that DNRM2 := sqrt( x'*x )
Parameters
N
N is INTEGER number of elements in input vector(s)
X
X is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
INCX
INCX is INTEGER, storage spacing between elements of X If INCX > 0, X(1+(i-1)*INCX) = x(i) for 1 <= i <= n If INCX < 0, X(1-(n-i)*INCX) = x(i) for 1 <= i <= n If INCX = 0, x isn't a vector so there is no need to call this subroutine. If you call it anyway, it will count x(1) in the vector norm N times.
Author
Edward Anderson, Lockheed Martin
Date
August 2016
Contributors:
Weslley Pereira, University of Colorado Denver, USA
Further Details:
Anderson E. (2017) Algorithm 978: Safe Scaling in the Level 1 BLAS ACM Trans Math Softw 44:1--28 https://doi.org/10.1145/3061665 Blue, James L. (1978) A Portable Fortran Program to Find the Euclidean Norm of a Vector ACM Trans Math Softw 4:15--23 https://doi.org/10.1145/355769.355771
Definition at line 88 of file dnrm2.f90.
Author
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