DQLT02
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
DQLT02 tests DORGQL, which generates an m-by-n matrix Q with
orthonornmal columns that is defined as the product of k elementary
reflectors.
Given the QL factorization of an m-by-n matrix A, DQLT02 generates
the orthogonal matrix Q defined by the factorization of the last k
columns of A; it compares L(m-n+1:m,n-k+1:n) with
Q(1:m,m-n+1:m)'*A(1:m,n-k+1:n), and checks that the columns of Q are
orthonormal.
orthonornmal columns that is defined as the product of k elementary
reflectors.
Given the QL factorization of an m-by-n matrix A, DQLT02 generates
the orthogonal matrix Q defined by the factorization of the last k
columns of A; it compares L(m-n+1:m,n-k+1:n) with
Q(1:m,m-n+1:m)'*A(1:m,n-k+1:n), and checks that the columns of Q are
orthonormal.
Arguments
| M |
(input) INTEGER
The number of rows of the matrix Q to be generated. M >= 0.
|
| N |
(input) INTEGER
The number of columns of the matrix Q to be generated.
M >= N >= 0. |
| K |
(input) INTEGER
The number of elementary reflectors whose product defines the
matrix Q. N >= K >= 0. |
| A |
(input) DOUBLE PRECISION array, dimension (LDA,N)
The m-by-n matrix A which was factorized by DQLT01.
|
| AF |
(input) DOUBLE PRECISION array, dimension (LDA,N)
Details of the QL factorization of A, as returned by DGEQLF.
See DGEQLF for further details. |
| Q |
(workspace) DOUBLE PRECISION array, dimension (LDA,N)
|
| L |
(workspace) DOUBLE PRECISION array, dimension (LDA,N)
|
| LDA |
(input) INTEGER
The leading dimension of the arrays A, AF, Q and L. LDA >= M.
|
| TAU |
(input) DOUBLE PRECISION array, dimension (N)
The scalar factors of the elementary reflectors corresponding
to the QL factorization in AF. |
| WORK |
(workspace) DOUBLE PRECISION array, dimension (LWORK)
|
| LWORK |
(input) INTEGER
The dimension of the array WORK.
|
| RWORK |
(workspace) DOUBLE PRECISION array, dimension (M)
|
| RESULT |
(output) DOUBLE PRECISION array, dimension (2)
The test ratios:
RESULT(1) = norm( L - Q'*A ) / ( M * norm(A) * EPS ) RESULT(2) = norm( I - Q'*Q ) / ( M * EPS ) |