ZTRTRI
November 2006
Purpose
ZTRTRI computes the inverse of a complex upper or lower triangular
matrix A.
This is the Level 3 BLAS version of the algorithm.
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*16 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 |
(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. |