dtrtri(l) [redhat man page]

DTRTRI(l)								 )								 DTRTRI(l)

NAME

       DTRTRI - compute the inverse of a real upper or lower triangular matrix A

SYNOPSIS

       SUBROUTINE DTRTRI( UPLO, DIAG, N, A, LDA, INFO )

	   CHARACTER	  DIAG, UPLO

	   INTEGER	  INFO, LDA, N

	   DOUBLE	  PRECISION A( LDA, * )

PURPOSE

       DTRTRI computes the inverse of a real upper or lower triangular matrix A.  This is the Level 3 BLAS version of the algorithm.

ARGUMENTS

       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/output) DOUBLE PRECISION array, dimension (LDA,N)
	       On  entry, the triangular matrix A.  If UPLO = 'U', the leading N-by-N upper triangular part of the array A contains the upper tri-
	       angular 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.  On exit, the (triangular) inverse of the original
	       matrix, in the same storage format.

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

       INFO    (output) INTEGER
	       = 0: successful exit
	       < 0: if INFO = -i, the i-th argument had an illegal value
	       > 0: if INFO = i, A(i,i) is exactly zero.  The triangular matrix is singular and its inverse can not be computed.

LAPACK version 3.0						   15 June 2000 							 DTRTRI(l)

dtrtri.f(3)							      LAPACK							       dtrtri.f(3)

NAME

       dtrtri.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dtrtri (UPLO, DIAG, N, A, LDA, INFO)
	   DTRTRI

Function/Subroutine Documentation
   subroutine dtrtri (characterUPLO, characterDIAG, integerN, double precision, dimension( lda, * )A, integerLDA, integerINFO)
       DTRTRI

       Purpose:

	    DTRTRI computes the inverse of a real upper or lower triangular
	    matrix A.

	    This is the Level 3 BLAS version of the algorithm.

       Parameters:
	   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)
		     On entry, 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.
		     On exit, the (triangular) inverse of the original matrix, in
		     the same storage format.

	   LDA

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

	   INFO

		     INFO is INTEGER
		     = 0: successful exit
		     < 0: if INFO = -i, the i-th argument had an illegal value
		     > 0: if INFO = i, A(i,i) is exactly zero.	The triangular
			  matrix is singular and its inverse can not be computed.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 110 of file dtrtri.f.

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

Version 3.4.1							  Sun May 26 2013						       dtrtri.f(3)