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