DGET54
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
DGET54 checks a generalized decomposition of the form
A = U*S*V' and B = U*T* V'
where ' means transpose and U and V are orthogonal.
Specifically,
RESULT = ||( A - U*S*V', B - U*T*V' )|| / (||( A, B )||*n*ulp )
A = U*S*V' and B = U*T* V'
where ' means transpose and U and V are orthogonal.
Specifically,
RESULT = ||( A - U*S*V', B - U*T*V' )|| / (||( A, B )||*n*ulp )
Arguments
| N |
(input) INTEGER
The size of the matrix. If it is zero, DGET54 does nothing.
It must be at least zero. |
| A |
(input) DOUBLE PRECISION array, dimension (LDA, N)
The original (unfactored) matrix A.
|
| LDA |
(input) INTEGER
The leading dimension of A. It must be at least 1
and at least N. |
| B |
(input) DOUBLE PRECISION array, dimension (LDB, N)
The original (unfactored) matrix B.
|
| LDB |
(input) INTEGER
The leading dimension of B. It must be at least 1
and at least N. |
| S |
(input) DOUBLE PRECISION array, dimension (LDS, N)
The factored matrix S.
|
| LDS |
(input) INTEGER
The leading dimension of S. It must be at least 1
and at least N. |
| T |
(input) DOUBLE PRECISION array, dimension (LDT, N)
The factored matrix T.
|
| LDT |
(input) INTEGER
The leading dimension of T. It must be at least 1
and at least N. |
| U |
(input) DOUBLE PRECISION array, dimension (LDU, N)
The orthogonal matrix on the left-hand side in the
decomposition. |
| LDU |
(input) INTEGER
The leading dimension of U. LDU must be at least N and
at least 1. |
| V |
(input) DOUBLE PRECISION array, dimension (LDV, N)
The orthogonal matrix on the left-hand side in the
decomposition. |
| LDV |
(input) INTEGER
The leading dimension of V. LDV must be at least N and
at least 1. |
| WORK |
(workspace) DOUBLE PRECISION array, dimension (3*N**2)
|
| RESULT |
(output) DOUBLE PRECISION
The value RESULT, It is currently limited to 1/ulp, to
avoid overflow. Errors are flagged by RESULT=10/ulp. |