TESTING/LIN/cqrt02.f(3) Library Functions Manual TESTING/LIN/cqrt02.f(3) NAME TESTING/LIN/cqrt02.f SYNOPSIS Functions/Subroutines subroutine cqrt02 (m, n, k, a, af, q, r, lda, tau, work, lwork, rwork, result) CQRT02 Function/Subroutine Documentation subroutine cqrt02 (integer m, integer n, integer k, complex, dimension( lda, * ) a, complex, dimension( lda, * ) af, complex, dimension( lda, * ) q, complex, dimension( lda, * ) r, integer lda, complex, dimension( * ) tau, complex, dimension( lwork ) work, integer lwork, real, dimension( * ) rwork, real, dimension( * ) result) CQRT02 Purpose: CQRT02 tests CUNGQR, which generates an m-by-n matrix Q with orthonormal columns that is defined as the product of k elementary reflectors. Given the QR factorization of an m-by-n matrix A, CQRT02 generates the orthogonal matrix Q defined by the factorization of the first k columns of A; it compares R(1:n,1:k) with Q(1:m,1:n)'*A(1:m,1:k), 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 COMPLEX array, dimension (LDA,N) The m-by-n matrix A which was factorized by CQRT01. AF AF is COMPLEX array, dimension (LDA,N) Details of the QR factorization of A, as returned by CGEQRF. See CGEQRF for further details. Q Q is COMPLEX array, dimension (LDA,N) R R is COMPLEX array, dimension (LDA,N) LDA LDA is INTEGER The leading dimension of the arrays A, AF, Q and R. LDA >= M. TAU TAU is COMPLEX array, dimension (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 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( R - 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 133 of file cqrt02.f. Author Generated automatically by Doxygen for LAPACK from the source code. LAPACK Version 3.12.0 TESTING/LIN/cqrt02.f(3)