TESTING/LIN/dqrt03.f(3)

NAME
TESTING/LIN/dqrt03.f

SYNOPSIS

  Functions/Subroutines
subroutine dqrt03 (m, n, k, af, c, cc, q, lda, tau, work, lwork, rwork, result)
DQRT03

Function/Subroutine Documentation

  subroutine dqrt03 (integer m, integer n, integer k, double precision, dimension( lda, * ) af, double precision, dimension( lda, * ) c, double precision, dimension( lda, * ) cc, double precision, dimension( lda, * ) q, integer lda, double precision, dimension( * ) tau, double precision, dimension( lwork ) work, integer lwork, double precision, dimension( * ) rwork, double precision, dimension( * ) result)

DQRT03

Purpose:

     DQRT03 tests DORMQR, which computes Q*C, Q'*C, C*Q or C*Q'.
     DQRT03 compares the results of a call to DORMQR with the results of
     forming Q explicitly by a call to DORGQR and then performing matrix
     multiplication by a call to DGEMM.

Parameters
    M

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

    N

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

    K

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

    AF

              AF is DOUBLE PRECISION array, dimension (LDA,N)
              Details of the QR factorization of an m-by-n matrix, as
              returned by DGEQRF. See DGEQRF 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,M)

    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 QR 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 m-by-m orthogonal matrix Q.
              RESULT(1) = norm( Q*C - Q*C )  / ( M * norm(C) * EPS )
              RESULT(2) = norm( C*Q - C*Q )  / ( M * norm(C) * EPS )
              RESULT(3) = norm( Q'*C - Q'*C )/ ( M * norm(C) * EPS )
              RESULT(4) = norm( C*Q' - C*Q' )/ ( M * norm(C) * EPS )

Author
    Univ. of Tennessee

    Univ. of California Berkeley

    Univ. of Colorado Denver

    NAG Ltd.

Definition at line 134 of file dqrt03.f.

Author

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