DSPT01
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
DSPT01 reconstructs a symmetric indefinite packed 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 and EPS is the machine epsilon.
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 and EPS is the machine epsilon.
Arguments
| UPLO |
(input) CHARACTER*1
Specifies whether the upper or lower triangular part of the
symmetric 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) DOUBLE PRECISION array, dimension (N*(N+1)/2)
The original symmetric matrix A, stored as a packed
triangular matrix. |
| AFAC |
(input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
The factored form of the matrix A, stored as a packed
triangular matrix. 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 DSPTRF. |
| IPIV |
(input) INTEGER array, dimension (N)
The pivot indices from DSPTRF.
|
| C |
(workspace) DOUBLE PRECISION array, dimension (LDC,N)
|
| LDC |
(integer) INTEGER
The leading dimension of the array C. LDC >= max(1,N).
|
| RWORK |
(workspace) DOUBLE PRECISION array, dimension (N)
|
| RESID |
(output) DOUBLE PRECISION
If UPLO = 'L', norm(L*D*L' - A) / ( N * norm(A) * EPS )
If UPLO = 'U', norm(U*D*U' - A) / ( N * norm(A) * EPS ) |