sqlt02.f - Man Page

subroutine sqlt02 (m, n, k, a, af, q, l, lda, tau, work, lwork, rwork, result)
SQLT02

SQLT02

Purpose:

 SQLT02 tests SORGQL, 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, SQLT02 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 REAL array, dimension (LDA,N)
          The m-by-n matrix A which was factorized by SQLT01.

AF

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

Q

          Q is REAL array, dimension (LDA,N)

L

          L is REAL array, dimension (LDA,N)

LDA

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

TAU

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

WORK

          WORK is REAL array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The dimension of the array WORK.

RWORK

          RWORK is REAL array, dimension (M)

RESULT

          RESULT is REAL 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 sqlt02.f.