redhat man page for ctrtri

CTRTRI(l)								 )								 CTRTRI(l)

NAME
       CTRTRI - compute the inverse of a complex upper or lower triangular matrix A

SYNOPSIS
       SUBROUTINE CTRTRI( UPLO, DIAG, N, A, LDA, INFO )

	   CHARACTER	  DIAG, UPLO

	   INTEGER	  INFO, LDA, N

	   COMPLEX	  A( LDA, * )

PURPOSE
       CTRTRI computes the inverse of a complex 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) COMPLEX 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 							 CTRTRI(l)