ZSYTRI2X
Purpose
ZSYTRI2X computes the inverse of a complex symmetric indefinite matrix
A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZSYTRF.
A using the factorization A = U*D*U**T or A = L*D*L**T computed by
ZSYTRF.
Arguments
| UPLO |
(input) CHARACTER*1
Specifies whether the details of the factorization are stored
as an upper or lower triangular matrix. = 'U': Upper triangular, form is A = U*D*U**T; = 'L': Lower triangular, form is A = L*D*L**T. |
| N |
(input) INTEGER
The order of the matrix A. N >= 0.
|
| A |
(input/output) DOUBLE COMPLEX array, dimension (LDA,N)
On entry, the NNB diagonal matrix D and the multipliers
used to obtain the factor U or L as computed by ZSYTRF. On exit, if INFO = 0, the (symmetric) inverse of the original matrix. If UPLO = 'U', the upper triangular part of the inverse is formed and the part of A below the diagonal is not referenced; if UPLO = 'L' the lower triangular part of the inverse is formed and the part of A above the diagonal is not referenced. |
| LDA |
(input) INTEGER
The leading dimension of the array A. LDA >= max(1,N).
|
| IPIV |
(input) INTEGER array, dimension (N)
Details of the interchanges and the NNB structure of D
as determined by ZSYTRF. |
| WORK |
(workspace) DOUBLE COMPLEX array, dimension (N+NNB+1,NNB+3)
|
| NB |
(input) INTEGER
Block size
|
| INFO |
(output) INTEGER
= 0: successful exit
< 0: if INFO = -i, the i-th argument had an illegal value > 0: if INFO = i, D(i,i) = 0; the matrix is singular and its inverse could not be computed. |