CHET01
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
CHET01 reconstructs a Hermitian indefinite matrix A from its
block L*D*L' or U*D*U' factorization and computes the residual
norm( C - A ) / ( N * norm(A) * EPS ),
where C is the reconstructed matrix, EPS is the machine epsilon,
L' is the conjugate transpose of L, and U' is the conjugate transpose
of U.
block L*D*L' or U*D*U' factorization and computes the residual
norm( C - A ) / ( N * norm(A) * EPS ),
where C is the reconstructed matrix, EPS is the machine epsilon,
L' is the conjugate transpose of L, and U' is the conjugate transpose
of U.
Arguments
| UPLO |
(input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
Hermitian matrix A is stored: = 'U': Upper triangular = 'L': Lower triangular |
| N |
(input) INTEGER
The number of rows and columns of the matrix A. N >= 0.
|
| A |
(input) COMPLEX array, dimension (LDA,N)
The original Hermitian matrix A.
|
| LDA |
(input) INTEGER
The leading dimension of the array A. LDA >= max(1,N)
|
| AFAC |
(input) COMPLEX array, dimension (LDAFAC,N)
The factored form of the matrix A. AFAC contains the block
diagonal matrix D and the multipliers used to obtain the factor L or U from the block L*D*L' or U*D*U' factorization as computed by CHETRF. |
| LDAFAC |
(input) INTEGER
The leading dimension of the array AFAC. LDAFAC >= max(1,N).
|
| IPIV |
(input) INTEGER array, dimension (N)
The pivot indices from CHETRF.
|
| C |
(workspace) COMPLEX array, dimension (LDC,N)
|
| LDC |
(integer) INTEGER
The leading dimension of the array C. LDC >= max(1,N).
|
| RWORK |
(workspace) REAL array, dimension (N)
|
| RESID |
(output) REAL
If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS ) |