dtrcon.f(3) [centos man page]

dtrcon.f(3)							      LAPACK							       dtrcon.f(3)

NAME

       dtrcon.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dtrcon (NORM, UPLO, DIAG, N, A, LDA, RCOND, WORK, IWORK, INFO)
	   DTRCON

Function/Subroutine Documentation
   subroutine dtrcon (characterNORM, characterUPLO, characterDIAG, integerN, double precision, dimension( lda, * )A, integerLDA, double
       precisionRCOND, double precision, dimension( * )WORK, integer, dimension( * )IWORK, integerINFO)
       DTRCON

       Purpose:

	    DTRCON estimates the reciprocal of the condition number of a
	    triangular matrix A, in either the 1-norm or the infinity-norm.

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

       Parameters:
	   NORM

		     NORM is CHARACTER*1
		     Specifies whether the 1-norm condition number or the
		     infinity-norm condition number is required:
		     = '1' or 'O':  1-norm;
		     = 'I':	    Infinity-norm.

	   UPLO

		     UPLO is CHARACTER*1
		     = 'U':  A is upper triangular;
		     = 'L':  A is lower triangular.

	   DIAG

		     DIAG is CHARACTER*1
		     = 'N':  A is non-unit triangular;
		     = 'U':  A is unit triangular.

	   N

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

	   A

		     A is DOUBLE PRECISION array, dimension (LDA,N)
		     The triangular matrix A.  If UPLO = 'U', the leading N-by-N
		     upper triangular part of the array A contains the upper
		     triangular matrix, and the strictly lower triangular part of
		     A is not referenced.  If UPLO = 'L', the leading N-by-N lower
		     triangular part of the array A contains the lower triangular
		     matrix, and the strictly upper triangular part of A is not
		     referenced.  If DIAG = 'U', the diagonal elements of A are
		     also not referenced and are assumed to be 1.

	   LDA

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

	   RCOND

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

	   WORK

		     WORK is DOUBLE PRECISION array, dimension (3*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 137 of file dtrcon.f.

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

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

Check Out this Related Man Page

DTRCON(l)								 )								 DTRCON(l)

NAME

       DTRCON - estimate the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm

SYNOPSIS

       SUBROUTINE DTRCON( NORM, UPLO, DIAG, N, A, LDA, RCOND, WORK, IWORK, INFO )

	   CHARACTER	  DIAG, NORM, UPLO

	   INTEGER	  INFO, LDA, N

	   DOUBLE	  PRECISION RCOND

	   INTEGER	  IWORK( * )

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

PURPOSE

       DTRCON estimates the reciprocal of the condition number of a triangular matrix A, in either the 1-norm or the infinity-norm.  The norm of A
       is computed and an estimate is obtained for norm(inv(A)), then the reciprocal of the condition number is computed 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 number is required:
	       = '1' or 'O':  1-norm;
	       = 'I':	      Infinity-norm.

       UPLO    (input) CHARACTER*1
	       = 'U':  A is upper triangular;
	       = 'L':  A is lower triangular.

       DIAG    (input) CHARACTER*1
	       = 'N':  A is non-unit triangular;
	       = 'U':  A is unit triangular.

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

       A       (input) DOUBLE PRECISION array, dimension (LDA,N)
	       The triangular matrix A.  If UPLO = 'U', the leading N-by-N upper triangular part of the array  A  contains  the  upper	triangular
	       matrix,	and the strictly lower triangular part of A is not referenced.	If UPLO = 'L', the leading N-by-N lower triangular part of
	       the array A contains the lower triangular matrix, and the strictly upper triangular part of A is not referenced.  If  DIAG  =  'U',
	       the diagonal elements of A are also not referenced and are assumed to be 1.

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

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

       WORK    (workspace) DOUBLE PRECISION array, dimension (3*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 							 DTRCON(l)

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dtrcon.f(3) [centos man page]

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