TESTING/LIN/dqlt02.f(3) Library Functions Manual TESTING/LIN/dqlt02.f(3) NAME TESTING/LIN/dqlt02.f SYNOPSIS Functions/Subroutines subroutine dqlt02 (m, n, k, a, af, q, l, lda, tau, work, lwork, rwork, result) DQLT02 Function/Subroutine Documentation subroutine dqlt02 (integer m, integer n, integer k, double precision, dimension( lda, * ) a, double precision, dimension( lda, * ) af, double precision, dimension( lda, * ) q, double precision, dimension( lda, * ) l, integer lda, double precision, dimension( * ) tau, double precision, dimension( lwork ) work, integer lwork, double precision, dimension( * ) rwork, double precision, dimension( * ) result) 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. Author Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 TESTING/LIN/dqlt02.f(3)