slqt03.f - Man Page

subroutine slqt03 (m, n, k, af, c, cc, q, lda, tau, work, lwork, rwork, result)
SLQT03

SLQT03

Purpose:

 SLQT03 tests SORMLQ, which computes Q*C, Q'*C, C*Q or C*Q'.

 SLQT03 compares the results of a call to SORMLQ with the results of
 forming Q explicitly by a call to SORGLQ and then performing matrix
 multiplication by a call to SGEMM.

Parameters

M

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

N

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

K

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

AF

          AF is REAL array, dimension (LDA,N)
          Details of the LQ factorization of an m-by-n matrix, as
          returned by SGELQF. See SGELQF 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,N)

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 LQ 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 n-by-n orthogonal matrix Q.
          RESULT(1) = norm( Q*C - Q*C )  / ( N * norm(C) * EPS )
          RESULT(2) = norm( C*Q - C*Q )  / ( N * norm(C) * EPS )
          RESULT(3) = norm( Q'*C - Q'*C )/ ( N * norm(C) * EPS )
          RESULT(4) = norm( C*Q' - C*Q' )/ ( N * norm(C) * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 134 of file slqt03.f.