pdlangs.c File Reference

Returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest value. More...

#include <math.h>
#include "superlu_ddefs.h"

Include dependency graph for pdlangs.c:

Functions
double	pdlangs (char *norm, SuperMatrix *A, gridinfo_t *grid)

Detailed Description

Returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest value.

Copyright (c) 2003, The Regents of the University of California, through Lawrence Berkeley National Laboratory (subject to receipt of any required approvals from U.S. Dept. of Energy)

All rights reserved.

The source code is distributed under BSD license, see the file License.txt at the top-level directory.

File name:  pdlangs.c
History:     Modified from lapack routine DLANGE

Function Documentation

pdlangs()

double pdlangs	(	char *	norm,
		SuperMatrix *	A,
		gridinfo_t *	grid
	)

    Purpose
    =======

    PDLANGS returns the value of the one norm, or the Frobenius norm, or
    the infinity norm, or the element of largest absolute value of a
    real matrix A.

    Description
    ===========

    PDLANGE returns the value

       PDLANGE = ( max(abs(A(i,j))), NORM = 'M' or 'm'
                 (
                 ( norm1(A),         NORM = '1', 'O' or 'o'
                 (
                 ( normI(A),         NORM = 'I' or 'i'
                 (
                 ( normF(A),         NORM = 'F', 'f', 'E' or 'e'

    where  norm1  denotes the  one norm of a matrix (maximum column sum),
    normI  denotes the  infinity norm  of a matrix  (maximum row sum) and
    normF  denotes the  Frobenius norm of a matrix (square root of sum of
    squares).  Note that  max(abs(A(i,j)))  is not a  matrix norm.

    Arguments
    =========

    NORM    (input) CHARACTER*1
            Specifies the value to be returned in DLANGE as described above.
    A       (input) SuperMatrix*
            The M by N sparse matrix A.
    GRID    (input) gridinof_t*
            The 2D process mesh.
   =====================================================================

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