DQPT01
Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
November 2006
November 2006
Purpose
DQPT01 tests the QR-factorization with pivoting of a matrix A. The
array AF contains the (possibly partial) QR-factorization of A, where
the upper triangle of AF(1:k,1:k) is a partial triangular factor,
the entries below the diagonal in the first k columns are the
Householder vectors, and the rest of AF contains a partially updated
matrix.
This function returns ||A*P - Q*R||/(||norm(A)||*eps*M)
array AF contains the (possibly partial) QR-factorization of A, where
the upper triangle of AF(1:k,1:k) is a partial triangular factor,
the entries below the diagonal in the first k columns are the
Householder vectors, and the rest of AF contains a partially updated
matrix.
This function returns ||A*P - Q*R||/(||norm(A)||*eps*M)
Arguments
| M |
(input) INTEGER
The number of rows of the matrices A and AF.
|
| N |
(input) INTEGER
The number of columns of the matrices A and AF.
|
| K |
(input) INTEGER
The number of columns of AF that have been reduced
to upper triangular form. |
| A |
(input) DOUBLE PRECISION array, dimension (LDA, N)
The original matrix A.
|
| AF |
(input) DOUBLE PRECISION array, dimension (LDA,N)
The (possibly partial) output of DGEQPF. The upper triangle
of AF(1:k,1:k) is a partial triangular factor, the entries below the diagonal in the first k columns are the Householder vectors, and the rest of AF contains a partially updated matrix. |
| LDA |
(input) INTEGER
The leading dimension of the arrays A and AF.
|
| TAU |
(input) DOUBLE PRECISION array, dimension (K)
Details of the Householder transformations as returned by
DGEQPF. |
| JPVT |
(input) INTEGER array, dimension (N)
Pivot information as returned by DGEQPF.
|
| WORK |
(workspace) DOUBLE PRECISION array, dimension (LWORK)
|
| LWORK |
(input) INTEGER
The length of the array WORK. LWORK >= M*N+N.
|