dsycon(l) [redhat man page]

DSYCON(l)								 )								 DSYCON(l)

NAME

       DSYCON  - estimate the reciprocal of the condition number (in the 1-norm) of a real symmetric matrix A using the factorization A = U*D*U**T
       or A = L*D*L**T computed by DSYTRF

SYNOPSIS

       SUBROUTINE DSYCON( UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, IWORK, INFO )

	   CHARACTER	  UPLO

	   INTEGER	  INFO, LDA, N

	   DOUBLE	  PRECISION ANORM, RCOND

	   INTEGER	  IPIV( * ), IWORK( * )

	   DOUBLE	  PRECISION A( LDA, * ), WORK( * )

PURPOSE

       DSYCON estimates the reciprocal of the condition number (in the 1-norm) of a real symmetric matrix A using the factorization A  =  U*D*U**T
       or  A  =  L*D*L**T computed by DSYTRF.  An estimate is obtained for norm(inv(A)), and the reciprocal of the condition number is computed as
       RCOND = 1 / (ANORM * norm(inv(A))).

ARGUMENTS

       UPLO    (input) CHARACTER*1
	       Specifies whether the details of the factorization are stored as an upper or lower triangular matrix.  =  'U':	Upper  triangular,
	       form is A = U*D*U**T;
	       = 'L':  Lower triangular, form is A = L*D*L**T.

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

       A       (input) DOUBLE PRECISION array, dimension (LDA,N)
	       The block diagonal matrix D and the multipliers used to obtain the factor U or L as computed by DSYTRF.

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

       IPIV    (input) INTEGER array, dimension (N)
	       Details of the interchanges and the block structure of D as determined by DSYTRF.

       ANORM   (input) DOUBLE PRECISION
	       The 1-norm of the original matrix A.

       RCOND   (output) DOUBLE PRECISION
	       The  reciprocal of the condition number of the matrix A, computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an estimate of the
	       1-norm of inv(A) computed in this routine.

       WORK    (workspace) DOUBLE PRECISION array, dimension (2*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 							 DSYCON(l)

dsycon.f(3)							      LAPACK							       dsycon.f(3)

NAME

       dsycon.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dsycon (UPLO, N, A, LDA, IPIV, ANORM, RCOND, WORK, IWORK, INFO)
	   DSYCON

Function/Subroutine Documentation
   subroutine dsycon (characterUPLO, integerN, double precision, dimension( lda, * )A, integerLDA, integer, dimension( * )IPIV, double
       precisionANORM, double precisionRCOND, double precision, dimension( * )WORK, integer, dimension( * )IWORK, integerINFO)
       DSYCON

       Purpose:

	    DSYCON estimates the reciprocal of the condition number (in the
	    1-norm) of a real symmetric matrix A using the factorization
	    A = U*D*U**T or A = L*D*L**T computed by DSYTRF.

	    An estimate is obtained for norm(inv(A)), and the reciprocal of the
	    condition number is computed as RCOND = 1 / (ANORM * norm(inv(A))).

       Parameters:
	   UPLO

		     UPLO is CHARACTER*1
		     Specifies whether the details of the factorization are stored
		     as an upper or lower triangular matrix.
		     = 'U':  Upper triangular, form is A = U*D*U**T;
		     = 'L':  Lower triangular, form is A = L*D*L**T.

	   N

		     N is INTEGER
		     The order of the matrix A.  N >= 0.

	   A

		     A is DOUBLE PRECISION array, dimension (LDA,N)
		     The block diagonal matrix D and the multipliers used to
		     obtain the factor U or L as computed by DSYTRF.

	   LDA

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

	   IPIV

		     IPIV is INTEGER array, dimension (N)
		     Details of the interchanges and the block structure of D
		     as determined by DSYTRF.

	   ANORM

		     ANORM is DOUBLE PRECISION
		     The 1-norm of the original matrix A.

	   RCOND

		     RCOND is DOUBLE PRECISION
		     The reciprocal of the condition number of the matrix A,
		     computed as RCOND = 1/(ANORM * AINVNM), where AINVNM is an
		     estimate of the 1-norm of inv(A) computed in this routine.

	   WORK

		     WORK is DOUBLE PRECISION array, dimension (2*N)

	   IWORK

		     IWORK is INTEGER array, dimension (N)

	   INFO

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

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 130 of file dsycon.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2							  Tue Sep 25 2012						       dsycon.f(3)