sqrt01()

subroutine sqrt01	(	integer	M,
		integer	N,
		real, dimension( lda, * )	A,
		real, dimension( lda, * )	AF,
		real, dimension( lda, * )	Q,
		real, dimension( lda, * )	R,
		integer	LDA,
		real, dimension( * )	TAU,
		real, dimension( lwork )	WORK,
		integer	LWORK,
		real, dimension( * )	RWORK,
		real, dimension( * )	RESULT
	)

SQRT01

Purpose:

 SQRT01 tests SGEQRF, which computes the QR factorization of an m-by-n
 matrix A, and partially tests SORGQR which forms the m-by-m
 orthogonal matrix Q.

 SQRT01 compares R with Q'*A, and checks that Q is orthogonal.

Parameters

[in]	M	M is INTEGER The number of rows of the matrix A. M >= 0.
[in]	N	N is INTEGER The number of columns of the matrix A. N >= 0.
[in]	A	A is REAL array, dimension (LDA,N) The m-by-n matrix A.
[out]	AF	AF is REAL array, dimension (LDA,N) Details of the QR factorization of A, as returned by SGEQRF. See SGEQRF for further details.
[out]	Q	Q is REAL array, dimension (LDA,M) The m-by-m orthogonal matrix Q.
[out]	R	R is REAL array, dimension (LDA,max(M,N))
[in]	LDA	LDA is INTEGER The leading dimension of the arrays A, AF, Q and R. LDA >= max(M,N).
[out]	TAU	TAU is REAL array, dimension (min(M,N)) The scalar factors of the elementary reflectors, as returned by SGEQRF.
[out]	WORK	WORK is REAL array, dimension (LWORK)
[in]	LWORK	LWORK is INTEGER The dimension of the array WORK.
[out]	RWORK	RWORK is REAL array, dimension (M)
[out]	RESULT	RESULT is REAL array, dimension (2) The test ratios: RESULT(1) = norm( R - Q'*A ) / ( M * norm(A) * EPS ) RESULT(2) = norm( I - Q'*Q ) / ( M * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.