TESTING/LIN/sqrt03.f(3)

NAME
TESTING/LIN/sqrt03.f

SYNOPSIS

  Functions/Subroutines
subroutine sqrt03 (m, n, k, af, c, cc, q, lda, tau, work, lwork, rwork, result)
SQRT03

Function/Subroutine Documentation

  subroutine sqrt03 (integer m, integer n, integer k, real, dimension( lda, * ) af, real, dimension( lda, * ) c, real, dimension( lda, * ) cc, real, dimension( lda, * ) q, integer lda, real, dimension( * ) tau, real, dimension( lwork ) work, integer lwork, real, dimension( * ) rwork, real, dimension( * ) result)

SQRT03

Purpose:

     SQRT03 tests SORMQR, which computes Q*C, Q'*C, C*Q or C*Q'.
     SQRT03 compares the results of a call to SORMQR with the results of
     forming Q explicitly by a call to SORGQR and then performing matrix
     multiplication by a call to SGEMM.

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 REAL array, dimension (LDA,N)
              Details of the QR factorization of an m-by-n matrix, as
              returned by SGEQRF. See SGEQRF for further details.

    C

              C is REAL array, dimension (LDA,N)

    CC

              CC is REAL array, dimension (LDA,N)

    Q

              Q is REAL array, dimension (LDA,M)

    LDA

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

    TAU

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

    WORK

              WORK is REAL 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 REAL array, dimension (M)

    RESULT

              RESULT is REAL 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 sqrt03.f.

Author

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