TESTING/LIN/drqt02.f(3) | Library Functions Manual | TESTING/LIN/drqt02.f(3) |
NAME
TESTING/LIN/drqt02.f
SYNOPSIS
Functions/Subroutines
subroutine drqt02 (m, n, k, a, af, q, r, lda, tau, work,
lwork, rwork, result)
DRQT02
Function/Subroutine Documentation
subroutine drqt02 (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)
DRQT02
Purpose:
DRQT02 tests DORGRQ, which generates an m-by-n matrix Q with orthonormal rows that is defined as the product of k elementary reflectors. Given the RQ factorization of an m-by-n matrix A, DRQT02 generates the orthogonal matrix Q defined by the factorization of the last k rows of A; it compares R(m-k+1:m,n-m+1:n) with A(m-k+1:m,1:n)*Q(n-m+1:n,1:n)', and checks that the rows of Q are orthonormal.
Parameters
M
M is INTEGER The number of rows of the matrix Q to be generated. M >= 0.
N
N is INTEGER The number of columns of the matrix Q to be generated. N >= M >= 0.
K
K is INTEGER The number of elementary reflectors whose product defines the matrix Q. M >= K >= 0.
A
A is DOUBLE PRECISION array, dimension (LDA,N) The m-by-n matrix A which was factorized by DRQT01.
AF
AF is DOUBLE PRECISION array, dimension (LDA,N) Details of the RQ factorization of A, as returned by DGERQF. See DGERQF for further details.
Q
Q is DOUBLE PRECISION array, dimension (LDA,N)
R
R is DOUBLE PRECISION array, dimension (LDA,M)
LDA
LDA is INTEGER The leading dimension of the arrays A, AF, Q and L. LDA >= N.
TAU
TAU is DOUBLE PRECISION array, dimension (M) The scalar factors of the elementary reflectors corresponding to the RQ factorization in AF.
WORK
WORK is DOUBLE PRECISION array, dimension (LWORK)
LWORK
LWORK is INTEGER The dimension of the array WORK.
RWORK
RWORK is DOUBLE PRECISION array, dimension (M)
RESULT
RESULT is DOUBLE PRECISION array, dimension (2) The test ratios: RESULT(1) = norm( R - A*Q' ) / ( N * norm(A) * EPS ) RESULT(2) = norm( I - Q*Q' ) / ( N * EPS )
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Definition at line 134 of file drqt02.f.
Author
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