lsd_mkb/lsd_mkb_superlu/superlu_seq/dlangs.c File Reference

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

Include dependency graph for dlangs.c:

Functions
double	dlangs (char *norm, SuperMatrix *A)

---

Function Documentation

double dlangs	(	char *	norm,
		SuperMatrix *	A
	)

 Purpose   
   =======

   DLANGS 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   
   ===========

   DLANGE returns the value

      DLANGE = ( 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.

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

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