lsd_mkb/lsd_mkb_superlu/superlu_seq/slacon.c File Reference

Estimates the 1-norm. More...

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

Include dependency graph for slacon.c:

Defines
#define	d_sign(a, b)   (b >= 0 ? fabs(a) : -fabs(a))
#define	i_dnnt(a)   ( a>=0 ? floor(a+.5) : -floor(.5-a) )
Functions
int	slacon_ (int *n, float *v, float *x, int *isgn, float *est, int *kase)

---

Detailed Description

Estimates the 1-norm.

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

---

Define Documentation

#define d_sign	(	a,
		b		)	(b >= 0 ? fabs(a) : -fabs(a))

#define i_dnnt

(

a

)

( a>=0 ? floor(a+.5) : -floor(.5-a) )

---

Function Documentation

int slacon_	(	int *	n,
		float *	v,
		float *	x,
		int *	isgn,
		float *	est,
		int *	kase
	)

   Purpose   
   =======

   SLACON estimates the 1-norm of a square matrix A.   
   Reverse communication is used for evaluating matrix-vector products.

   Arguments   
   =========

   N      (input) INT
          The order of the matrix.  N >= 1.

   V      (workspace) FLOAT PRECISION array, dimension (N)   
          On the final return, V = A*W,  where  EST = norm(V)/norm(W)   
          (W is not returned).

   X      (input/output) FLOAT PRECISION array, dimension (N)   
          On an intermediate return, X should be overwritten by   
                A * X,   if KASE=1,   
                A' * X,  if KASE=2,
         and SLACON must be re-called with all the other parameters   
          unchanged.

   ISGN   (workspace) INT array, dimension (N)

   EST    (output) FLOAT PRECISION   
          An estimate (a lower bound) for norm(A).

   KASE   (input/output) INT
          On the initial call to SLACON, KASE should be 0.   
          On an intermediate return, KASE will be 1 or 2, indicating   
          whether X should be overwritten by A * X  or A' * X.   
          On the final return from SLACON, KASE will again be 0.

   Further Details   
   ======= =======

   Contributed by Nick Higham, University of Manchester.   
   Originally named CONEST, dated March 16, 1988.

   Reference: N.J. Higham, "FORTRAN codes for estimating the one-norm of 
   a real or complex matrix, with applications to condition estimation", 
   ACM Trans. Math. Soft., vol. 14, no. 4, pp. 381-396, December 1988.   
   ===================================================================== 
 

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