DTRTRI(l)		LAPACK routine (version	1.1)		    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.


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