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RedHat 9 (Linux i386) - man page for sgecon (redhat section l)

SGECON(l)					)					SGECON(l)

NAME
       SGECON  -  estimate  the reciprocal of the condition number of a general real matrix A, in
       either the 1-norm or the infinity-norm, using the LU factorization computed by SGETRF

SYNOPSIS
       SUBROUTINE SGECON( NORM, N, A, LDA, ANORM, RCOND, WORK, IWORK, INFO )

	   CHARACTER	  NORM

	   INTEGER	  INFO, LDA, N

	   REAL 	  ANORM, RCOND

	   INTEGER	  IWORK( * )

	   REAL 	  A( LDA, * ), WORK( * )

PURPOSE
       SGECON estimates the reciprocal of the condition number of a general  real  matrix  A,  in
       either the 1-norm or the infinity-norm, using the LU factorization computed by SGETRF.  An
       estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is  com-
       puted as
	  RCOND = 1 / ( norm(A) * norm(inv(A)) ).

ARGUMENTS
       NORM    (input) CHARACTER*1
	       Specifies  whether the 1-norm condition number or the infinity-norm condition num-
	       ber is required:
	       = '1' or 'O':  1-norm;
	       = 'I':	      Infinity-norm.

       N       (input) INTEGER
	       The order of the matrix A.  N >= 0.

       A       (input) REAL array, dimension (LDA,N)
	       The factors L and U from the factorization A = P*L*U as computed by SGETRF.

       LDA     (input) INTEGER
	       The leading dimension of the array A.  LDA >= max(1,N).

       ANORM   (input) REAL
	       If NORM = '1' or 'O', the 1-norm of the original matrix A.  If  NORM  =	'I',  the
	       infinity-norm of the original matrix A.

       RCOND   (output) REAL
	       The  reciprocal	of  the  condition  number  of	the matrix A, computed as RCOND =
	       1/(norm(A) * norm(inv(A))).

       WORK    (workspace) REAL array, dimension (4*N)

       IWORK   (workspace) INTEGER array, dimension (N)

       INFO    (output) INTEGER
	       = 0:  successful exit
	       < 0:  if INFO = -i, the i-th argument had an illegal value

LAPACK version 3.0			   15 June 2000 				SGECON(l)


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