ZPTTRS
Purpose
ZPTTRS solves a tridiagonal system of the form
A * X = B
using the factorization A = U**H *D* U or A = L*D*L**H computed by ZPTTRF.
D is a diagonal matrix specified in the vector D, U (or L) is a unit
bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
the vector E, and X and B are N by NRHS matrices.
A * X = B
using the factorization A = U**H *D* U or A = L*D*L**H computed by ZPTTRF.
D is a diagonal matrix specified in the vector D, U (or L) is a unit
bidiagonal matrix whose superdiagonal (subdiagonal) is specified in
the vector E, and X and B are N by NRHS matrices.
Arguments
| UPLO |
(input) CHARACTER*1
Specifies the form of the factorization and whether the
vector E is the superdiagonal of the upper bidiagonal factor U or the subdiagonal of the lower bidiagonal factor L. = 'U': A = U**H *D*U, E is the superdiagonal of U = 'L': A = L*D*L**H, E is the subdiagonal of L |
| N |
(input) INTEGER
The order of the tridiagonal matrix A. N >= 0.
|
| NRHS |
(input) INTEGER
The number of right hand sides, i.e., the number of columns
of the matrix B. NRHS >= 0. |
| D |
(input) DOUBLE PRECISION array, dimension (N)
The n diagonal elements of the diagonal matrix D from the
factorization A = U**H *D*U or A = L*D*L**H. |
| E |
(input) COMPLEX*16 array, dimension (N-1)
If UPLO = 'U', the (n-1) superdiagonal elements of the unit
bidiagonal factor U from the factorization A = U**H*D*U. If UPLO = 'L', the (n-1) subdiagonal elements of the unit bidiagonal factor L from the factorization A = L*D*L**H. |
| B |
(input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)
On entry, the right hand side vectors B for the system of
linear equations. On exit, the solution vectors, X. |
| LDB |
(input) INTEGER
The leading dimension of the array B. LDB >= max(1,N).
|
| INFO |
(output) INTEGER
= 0: successful exit
< 0: if INFO = -k, the k-th argument had an illegal value |