SRC/slangs.c File Reference

Returns the value of the one norm. More...

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

Functions
float	slangs (char *norm, SuperMatrix *A)

---

Detailed Description

 -- SuperLU routine (version 2.0) --
 Univ. of California Berkeley, Xerox Palo Alto Research Center,
 and Lawrence Berkeley National Lab.
 November 15, 1997

 Modified from lapack routine SLANGE 
 

---

Function Documentation

float slangs	(	char *	norm,
		SuperMatrix *	A
	)

 Purpose   
   =======

   SLANGS 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   
   ===========

   SLANGE returns the value

      SLANGE = ( 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 SLANGE as described above.   
   A       (input) SuperMatrix*
           The M by N sparse matrix A.

  =====================================================================