SRC/zlacon.c File Reference

Estimates the 1-norm. More...

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

Functions

int zlacon_ (int *n, doublecomplex *v, doublecomplex *x, double *est, int *kase)

Detailed Description

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

Function Documentation

int zlacon_	(	int *	n,
		doublecomplex *	v,
		doublecomplex *	x,
		double *	est,
		int *	kase
	)

   Purpose   
   =======

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

   X      (input/output) DOUBLE COMPLEX PRECISION array, dimension (N)   
          On an intermediate return, X should be overwritten by   
                A * X,   if KASE=1,   
                A' * X,  if KASE=2,
          where A' is the conjugate transpose of A,
         and ZLACON must be re-called with all the other parameters   
          unchanged.

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

   KASE   (input/output) INT
          On the initial call to ZLACON, 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 ZLACON, 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.   
   =====================================================================


Functions
int	zlacon_ (int n, doublecomplex v, doublecomplex x, double est, int *kase)