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TESTING/LIN/srqt02.f(3) LAPACK TESTING/LIN/srqt02.f(3)

TESTING/LIN/srqt02.f


subroutine srqt02 (m, n, k, a, af, q, r, lda, tau, work, lwork, rwork, result)
SRQT02

SRQT02

Purpose:


SRQT02 tests SORGRQ, 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, SRQT02 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 REAL array, dimension (LDA,N)
The m-by-n matrix A which was factorized by SRQT01.

AF


AF is REAL array, dimension (LDA,N)
Details of the RQ factorization of A, as returned by SGERQF.
See SGERQF for further details.

Q


Q is REAL array, dimension (LDA,N)

R


R is REAL array, dimension (LDA,M)

LDA


LDA is INTEGER
The leading dimension of the arrays A, AF, Q and L. LDA >= N.

TAU


TAU is REAL array, dimension (M)
The scalar factors of the elementary reflectors corresponding
to the RQ factorization in AF.

WORK


WORK is REAL array, dimension (LWORK)

LWORK


LWORK is INTEGER
The dimension of the array WORK.

RWORK


RWORK is REAL array, dimension (M)

RESULT


RESULT is REAL 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 srqt02.f.

Generated automatically by Doxygen for LAPACK from the source code.

Sun Jan 12 2025 15:13:35 Version 3.12.1

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