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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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LAPACK 3.11.0
LAPACK: Linear Algebra PACKage
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| subroutine dqrt02 | ( | integer | M, |
| integer | N, | ||
| integer | K, | ||
| double precision, dimension( lda, * ) | A, | ||
| double precision, dimension( lda, * ) | AF, | ||
| double precision, dimension( lda, * ) | Q, | ||
| double precision, dimension( lda, * ) | R, | ||
| integer | LDA, | ||
| double precision, dimension( * ) | TAU, | ||
| double precision, dimension( lwork ) | WORK, | ||
| integer | LWORK, | ||
| double precision, dimension( * ) | RWORK, | ||
| double precision, dimension( * ) | RESULT | ||
| ) |
DQRT02
DQRT02 tests DORGQR, which generates an m-by-n matrix Q with orthonornmal columns that is defined as the product of k elementary reflectors. Given the QR factorization of an m-by-n matrix A, DQRT02 generates the orthogonal matrix Q defined by the factorization of the first k columns of A; it compares R(1:n,1:k) with Q(1:m,1:n)'*A(1:m,1:k), and checks that the columns of Q are orthonormal.
| [in] | M | M is INTEGER
The number of rows of the matrix Q to be generated. M >= 0. |
| [in] | N | N is INTEGER
The number of columns of the matrix Q to be generated.
M >= N >= 0. |
| [in] | K | K is INTEGER
The number of elementary reflectors whose product defines the
matrix Q. N >= K >= 0. |
| [in] | A | A is DOUBLE PRECISION array, dimension (LDA,N)
The m-by-n matrix A which was factorized by DQRT01. |
| [in] | AF | AF is DOUBLE PRECISION array, dimension (LDA,N)
Details of the QR factorization of A, as returned by DGEQRF.
See DGEQRF for further details. |
| [out] | Q | Q is DOUBLE PRECISION array, dimension (LDA,N) |
| [out] | R | R is DOUBLE PRECISION array, dimension (LDA,N) |
| [in] | LDA | LDA is INTEGER
The leading dimension of the arrays A, AF, Q and R. LDA >= M. |
| [in] | TAU | TAU is DOUBLE PRECISION array, dimension (N)
The scalar factors of the elementary reflectors corresponding
to the QR factorization in AF. |
| [out] | WORK | WORK is DOUBLE PRECISION array, dimension (LWORK) |
| [in] | LWORK | LWORK is INTEGER
The dimension of the array WORK. |
| [out] | RWORK | RWORK is DOUBLE PRECISION array, dimension (M) |
| [out] | RESULT | RESULT is DOUBLE PRECISION array, dimension (2)
The test ratios:
RESULT(1) = norm( R - Q'*A ) / ( M * norm(A) * EPS )
RESULT(2) = norm( I - Q'*Q ) / ( M * EPS ) |
1.9.4