NAME

TESTING/LIN/dqrt01p.f

SYNOPSIS

Functions/Subroutines

subroutine dqrt01p (m, n, a, af, q, r, lda, tau, work, lwork, rwork, result)
DQRT01P

Function/Subroutine Documentation

subroutine dqrt01p (integer m, integer n, 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)

DQRT01P

Purpose:



 DQRT01P tests DGEQRFP, which computes the QR factorization of an m-by-n


 matrix A, and partially tests DORGQR which forms the m-by-m


 orthogonal matrix Q.


 DQRT01P compares R with Q'*A, and checks that Q is orthogonal.

Parameters



          M is INTEGER


          The number of rows of the matrix A.  M >= 0.



          N is INTEGER


          The number of columns of the matrix A.  N >= 0.



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


          The m-by-n matrix A.



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


          Details of the QR factorization of A, as returned by DGEQRFP.


          See DGEQRFP for further details.



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


          The m-by-m orthogonal matrix Q.



          R is DOUBLE PRECISION array, dimension (LDA,max(M,N))

LDA



          LDA is INTEGER


          The leading dimension of the arrays A, AF, Q and R.


          LDA >= max(M,N).

TAU



          TAU is DOUBLE PRECISION array, dimension (min(M,N))


          The scalar factors of the elementary reflectors, as returned


          by DGEQRFP.

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 - 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.

Definition at line 124 of file dqrt01p.f.

Author

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