cqrt03.f - Man Page

subroutine cqrt03 (m, n, k, af, c, cc, q, lda, tau, work, lwork, rwork, result)
CQRT03

CQRT03

Purpose:

 CQRT03 tests CUNMQR, which computes Q*C, Q'*C, C*Q or C*Q'.

 CQRT03 compares the results of a call to CUNMQR with the results of
 forming Q explicitly by a call to CUNGQR and then performing matrix
 multiplication by a call to CGEMM.

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

C

          C is COMPLEX array, dimension (LDA,N)

CC

          CC is COMPLEX array, dimension (LDA,N)

Q

          Q is COMPLEX array, dimension (LDA,M)

LDA

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

TAU

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

WORK

          WORK is COMPLEX 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 cqrt03.f.