SUBROUTINE ZQRT01( M, N, A, AF, Q, R, LDA, TAU, WORK, LWORK, \$ RWORK, RESULT ) * * -- LAPACK test routine (version 3.1) -- * Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. * November 2006 * * .. Scalar Arguments .. INTEGER LDA, LWORK, M, N * .. * .. Array Arguments .. DOUBLE PRECISION RESULT( * ), RWORK( * ) COMPLEX*16 A( LDA, * ), AF( LDA, * ), Q( LDA, * ), \$ R( LDA, * ), TAU( * ), WORK( LWORK ) * .. * * Purpose * ======= * * ZQRT01 tests ZGEQRF, which computes the QR factorization of an m-by-n * matrix A, and partially tests ZUNGQR which forms the m-by-m * orthogonal matrix Q. * * ZQRT01 compares R with Q'*A, and checks that Q is orthogonal. * * Arguments * ========= * * M (input) INTEGER * The number of rows of the matrix A. M >= 0. * * N (input) INTEGER * The number of columns of the matrix A. N >= 0. * * A (input) COMPLEX*16 array, dimension (LDA,N) * The m-by-n matrix A. * * AF (output) COMPLEX*16 array, dimension (LDA,N) * Details of the QR factorization of A, as returned by ZGEQRF. * See ZGEQRF for further details. * * Q (output) COMPLEX*16 array, dimension (LDA,M) * The m-by-m orthogonal matrix Q. * * R (workspace) COMPLEX*16 array, dimension (LDA,max(M,N)) * * LDA (input) INTEGER * The leading dimension of the arrays A, AF, Q and R. * LDA >= max(M,N). * * TAU (output) COMPLEX*16 array, dimension (min(M,N)) * The scalar factors of the elementary reflectors, as returned * by ZGEQRF. * * WORK (workspace) COMPLEX*16 array, dimension (LWORK) * * LWORK (input) INTEGER * The dimension of the array WORK. * * RWORK (workspace) DOUBLE PRECISION array, dimension (M) * * RESULT (output) DOUBLE PRECISION array, dimension (2) * The test ratios: * RESULT(1) = norm( R - Q'*A ) / ( M * norm(A) * EPS ) * RESULT(2) = norm( I - Q'*Q ) / ( M * EPS ) * * ===================================================================== * * .. Parameters .. DOUBLE PRECISION ZERO, ONE PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) COMPLEX*16 ROGUE PARAMETER ( ROGUE = ( -1.0D+10, -1.0D+10 ) ) * .. * .. Local Scalars .. INTEGER INFO, MINMN DOUBLE PRECISION ANORM, EPS, RESID * .. * .. External Functions .. DOUBLE PRECISION DLAMCH, ZLANGE, ZLANSY EXTERNAL DLAMCH, ZLANGE, ZLANSY * .. * .. External Subroutines .. EXTERNAL ZGEMM, ZGEQRF, ZHERK, ZLACPY, ZLASET, ZUNGQR * .. * .. Intrinsic Functions .. INTRINSIC DBLE, DCMPLX, MAX, MIN * .. * .. Scalars in Common .. CHARACTER*32 SRNAMT * .. * .. Common blocks .. COMMON / SRNAMC / SRNAMT * .. * .. Executable Statements .. * MINMN = MIN( M, N ) EPS = DLAMCH( 'Epsilon' ) * * Copy the matrix A to the array AF. * CALL ZLACPY( 'Full', M, N, A, LDA, AF, LDA ) * * Factorize the matrix A in the array AF. * SRNAMT = 'ZGEQRF' CALL ZGEQRF( M, N, AF, LDA, TAU, WORK, LWORK, INFO ) * * Copy details of Q * CALL ZLASET( 'Full', M, M, ROGUE, ROGUE, Q, LDA ) CALL ZLACPY( 'Lower', M-1, N, AF( 2, 1 ), LDA, Q( 2, 1 ), LDA ) * * Generate the m-by-m matrix Q * SRNAMT = 'ZUNGQR' CALL ZUNGQR( M, M, MINMN, Q, LDA, TAU, WORK, LWORK, INFO ) * * Copy R * CALL ZLASET( 'Full', M, N, DCMPLX( ZERO ), DCMPLX( ZERO ), R, \$ LDA ) CALL ZLACPY( 'Upper', M, N, AF, LDA, R, LDA ) * * Compute R - Q'*A * CALL ZGEMM( 'Conjugate transpose', 'No transpose', M, N, M, \$ DCMPLX( -ONE ), Q, LDA, A, LDA, DCMPLX( ONE ), R, \$ LDA ) * * Compute norm( R - Q'*A ) / ( M * norm(A) * EPS ) . * ANORM = ZLANGE( '1', M, N, A, LDA, RWORK ) RESID = ZLANGE( '1', M, N, R, LDA, RWORK ) IF( ANORM.GT.ZERO ) THEN RESULT( 1 ) = ( ( RESID / DBLE( MAX( 1, M ) ) ) / ANORM ) / EPS ELSE RESULT( 1 ) = ZERO END IF * * Compute I - Q'*Q * CALL ZLASET( 'Full', M, M, DCMPLX( ZERO ), DCMPLX( ONE ), R, LDA ) CALL ZHERK( 'Upper', 'Conjugate transpose', M, M, -ONE, Q, LDA, \$ ONE, R, LDA ) * * Compute norm( I - Q'*Q ) / ( M * EPS ) . * RESID = ZLANSY( '1', 'Upper', M, R, LDA, RWORK ) * RESULT( 2 ) = ( RESID / DBLE( MAX( 1, M ) ) ) / EPS * RETURN * * End of ZQRT01 * END