dqlt02.f - Man Page

subroutine dqlt02 (m, n, k, a, af, q, l, lda, tau, work, lwork, rwork, result)
DQLT02

DQLT02

Purpose:

 DQLT02 tests DORGQL, which generates an m-by-n matrix Q with
 orthonormal columns that is defined as the product of k elementary
 reflectors.

 Given the QL factorization of an m-by-n matrix A, DQLT02 generates
 the orthogonal matrix Q defined by the factorization of the last k
 columns of A; it compares L(m-n+1:m,n-k+1:n) with
 Q(1:m,m-n+1:m)'*A(1:m,n-k+1:n), and checks that the columns of Q are
 orthonormal.

Parameters

M

          M is INTEGER
          The number of rows of the matrix Q to be generated.  M >= 0.

N

          N is INTEGER
          The number of columns of the matrix Q to be generated.
          M >= N >= 0.

K

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

A

          A is DOUBLE PRECISION array, dimension (LDA,N)
          The m-by-n matrix A which was factorized by DQLT01.

AF

          AF is DOUBLE PRECISION array, dimension (LDA,N)
          Details of the QL factorization of A, as returned by DGEQLF.
          See DGEQLF for further details.

Q

          Q is DOUBLE PRECISION array, dimension (LDA,N)

L

          L is DOUBLE PRECISION array, dimension (LDA,N)

LDA

          LDA is INTEGER
          The leading dimension of the arrays A, AF, Q and L. LDA >= M.

TAU

          TAU is DOUBLE PRECISION array, dimension (N)
          The scalar factors of the elementary reflectors corresponding
          to the QL factorization in AF.

WORK

          WORK is DOUBLE PRECISION array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The dimension of the array WORK.

RWORK

          RWORK is DOUBLE PRECISION array, dimension (M)

RESULT

          RESULT is DOUBLE PRECISION array, dimension (2)
          The test ratios:
          RESULT(1) = norm( L - Q'*A ) / ( M * norm(A) * EPS )
          RESULT(2) = norm( I - Q'*Q ) / ( M * EPS )

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 134 of file dqlt02.f.