dtrti2(3P) Sun Performance Library dtrti2(3P)NAMEdtrti2 - compute the inverse of a real upper or lower triangular matrix
SYNOPSIS
SUBROUTINE DTRTI2(UPLO, DIAG, N, A, LDA, INFO)
CHARACTER * 1 UPLO, DIAG
INTEGER N, LDA, INFO
DOUBLE PRECISION A(LDA,*)
SUBROUTINE DTRTI2_64(UPLO, DIAG, N, A, LDA, INFO)
CHARACTER * 1 UPLO, DIAG
INTEGER*8 N, LDA, INFO
DOUBLE PRECISION A(LDA,*)
F95 INTERFACE
SUBROUTINE TRTI2(UPLO, DIAG, [N], A, [LDA], [INFO])
CHARACTER(LEN=1) :: UPLO, DIAG
INTEGER :: N, LDA, INFO
REAL(8), DIMENSION(:,:) :: A
SUBROUTINE TRTI2_64(UPLO, DIAG, [N], A, [LDA], [INFO])
CHARACTER(LEN=1) :: UPLO, DIAG
INTEGER(8) :: N, LDA, INFO
REAL(8), DIMENSION(:,:) :: A
C INTERFACE
#include <sunperf.h>
void dtrti2(char uplo, char diag, int n, double *a, int lda, int
*info);
void dtrti2_64(char uplo, char diag, long n, double *a, long lda, long
*info);
PURPOSEdtrti2 computes the inverse of a real upper or lower triangular matrix.
This is the Level 2 BLAS version of the algorithm.
ARGUMENTS
UPLO (input)
Specifies whether the matrix A is upper or lower triangular.
= 'U': Upper triangular
= 'L': Lower triangular
DIAG (input)
Specifies whether or not the matrix A is unit triangular. =
'N': Non-unit triangular
= 'U': Unit triangular
N (input) The order of the matrix A. N >= 0.
A (input/output)
On entry, the triangular matrix A. If UPLO = 'U', the lead‐
ing 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 (input)
The leading dimension of the array A. LDA >= max(1,N).
INFO (output)
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value
6 Mar 2009 dtrti2(3P)