TESTING/LIN/dqrt03.f(3) Library Functions Manual TESTING/LIN/dqrt03.f(3)

TESTING/LIN/dqrt03.f


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

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.

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