Provided by: liblapack-doc_3.12.0-3build1.1_all
NAME
nrm2 - nrm2: || x ||_2
SYNOPSIS
Functions real(wp) function dnrm2 (n, x, incx) DNRM2 real(wp) function dznrm2 (n, x, incx) DZNRM2 real(wp) function scnrm2 (n, x, incx) SCNRM2 real(wp) function snrm2 (n, x, incx) SNRM2
Detailed Description
Function 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 real(wp) function dznrm2 (integer n, complex(wp), dimension(*) x, integer incx) DZNRM2 Purpose: DZNRM2 returns the euclidean norm of a vector via the function name, so that DZNRM2 := sqrt( x**H*x ) Parameters N N is INTEGER number of elements in input vector(s) X X is COMPLEX*16 array, dimension (N) complex vector with N elements 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 real(wp) function scnrm2 (integer n, complex(wp), dimension(*) x, integer incx) SCNRM2 Purpose: SCNRM2 returns the euclidean norm of a vector via the function name, so that SCNRM2 := sqrt( x**H*x ) Parameters N N is INTEGER number of elements in input vector(s) X X is COMPLEX array, dimension (N) complex vector with N elements 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 real(wp) function snrm2 (integer n, real(wp), dimension(*) x, integer incx) SNRM2 Purpose: SNRM2 returns the euclidean norm of a vector via the function name, so that SNRM2 := sqrt( x'*x ). Parameters N N is INTEGER number of elements in input vector(s) X X is REAL 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
Author
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