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Man Pages
TESTING/LIN/drqt03.f(3) LAPACK TESTING/LIN/drqt03.f(3)

TESTING/LIN/drqt03.f


subroutine drqt03 (m, n, k, af, c, cc, q, lda, tau, work, lwork, rwork, result)
DRQT03

DRQT03

Purpose:


DRQT03 tests DORMRQ, which computes Q*C, Q'*C, C*Q or C*Q'.
DRQT03 compares the results of a call to DORMRQ with the results of
forming Q explicitly by a call to DORGRQ and then performing matrix
multiplication by a call to DGEMM.

Parameters

M


M is INTEGER
The number of rows or columns of the matrix C; C is n-by-m if
Q is applied from the left, or m-by-n if Q is applied from
the right. M >= 0.

N


N is INTEGER
The order of the orthogonal matrix Q. N >= 0.

K


K is INTEGER
The number of elementary reflectors whose product defines the
orthogonal matrix Q. N >= K >= 0.

AF


AF is DOUBLE PRECISION array, dimension (LDA,N)
Details of the RQ factorization of an m-by-n matrix, as
returned by DGERQF. See SGERQF for further details.

C


C is DOUBLE PRECISION array, dimension (LDA,N)

CC


CC is DOUBLE PRECISION array, dimension (LDA,N)

Q


Q is DOUBLE PRECISION array, dimension (LDA,N)

LDA


LDA is INTEGER
The leading dimension of the arrays AF, C, CC, and Q.

TAU


TAU is DOUBLE PRECISION array, dimension (min(M,N))
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 length of WORK. LWORK must be at least M, and should be
M*NB, where NB is the blocksize for this environment.

RWORK


RWORK is DOUBLE PRECISION array, dimension (M)

RESULT


RESULT is DOUBLE PRECISION array, dimension (4)
The test ratios compare two techniques for multiplying a
random matrix C by an n-by-n orthogonal matrix Q.
RESULT(1) = norm( Q*C - Q*C ) / ( N * norm(C) * EPS )
RESULT(2) = norm( C*Q - C*Q ) / ( N * norm(C) * EPS )
RESULT(3) = norm( Q'*C - Q'*C )/ ( N * norm(C) * EPS )
RESULT(4) = norm( C*Q' - C*Q' )/ ( N * norm(C) * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 134 of file drqt03.f.

Generated automatically by Doxygen for LAPACK from the source code.

Sun Jan 12 2025 15:13:34 Version 3.12.1

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