SRC/pzlangs.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_zdefs.h"

Functions/Subroutines

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


Detailed Description

 File name:	pzlangs.c
 History:     Modified from lapack routine ZLANGE
 

Function Documentation

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

 
    Purpose   
    =======

    PZLANGS 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   
    ===========

    PZLANGE returns the value

       PZLANGE = ( 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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