.TH "SRC/dtrtri.f" 3 "Version 3.12.0" "LAPACK" \" -*- nroff -*- .ad l .nh .SH NAME SRC/dtrtri.f .SH SYNOPSIS .br .PP .SS "Functions/Subroutines" .in +1c .ti -1c .RI "subroutine \fBdtrtri\fP (uplo, diag, n, a, lda, info)" .br .RI "\fBDTRTRI\fP " .in -1c .SH "Function/Subroutine Documentation" .PP .SS "subroutine dtrtri (character uplo, character diag, integer n, double precision, dimension( lda, * ) a, integer lda, integer info)" .PP \fBDTRTRI\fP .PP \fBPurpose:\fP .RS 4 .PP .nf !> !> DTRTRI computes the inverse of a real upper or lower triangular !> matrix A\&. !> !> This is the Level 3 BLAS version of the algorithm\&. !> .fi .PP .RE .PP \fBParameters\fP .RS 4 \fIUPLO\fP .PP .nf !> UPLO is CHARACTER*1 !> = 'U': A is upper triangular; !> = 'L': A is lower triangular\&. !> .fi .PP .br \fIDIAG\fP .PP .nf !> DIAG is CHARACTER*1 !> = 'N': A is non-unit triangular; !> = 'U': A is unit triangular\&. !> .fi .PP .br \fIN\fP .PP .nf !> N is INTEGER !> The order of the matrix A\&. N >= 0\&. !> .fi .PP .br \fIA\fP .PP .nf !> 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\&. !> .fi .PP .br \fILDA\fP .PP .nf !> LDA is INTEGER !> The leading dimension of the array A\&. LDA >= max(1,N)\&. !> .fi .PP .br \fIINFO\fP .PP .nf !> 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\&. !> .fi .PP .RE .PP \fBAuthor\fP .RS 4 Univ\&. of Tennessee .PP Univ\&. of California Berkeley .PP Univ\&. of Colorado Denver .PP NAG Ltd\&. .RE .PP .PP Definition at line \fB108\fP of file \fBdtrtri\&.f\fP\&. .SH "Author" .PP Generated automatically by Doxygen for LAPACK from the source code\&.