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authorjason <jason@8a072113-8704-0410-8d35-dd094bca7971>2008-10-28 01:38:50 +0000
committerjason <jason@8a072113-8704-0410-8d35-dd094bca7971>2008-10-28 01:38:50 +0000
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+ SUBROUTINE ZRQT01( 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
+* =======
+*
+* ZRQT01 tests ZGERQF, which computes the RQ factorization of an m-by-n
+* matrix A, and partially tests ZUNGRQ which forms the n-by-n
+* orthogonal matrix Q.
+*
+* ZRQT01 compares R with A*Q', 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 RQ factorization of A, as returned by ZGERQF.
+* See ZGERQF for further details.
+*
+* Q (output) COMPLEX*16 array, dimension (LDA,N)
+* The n-by-n 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 L.
+* LDA >= max(M,N).
+*
+* TAU (output) COMPLEX*16 array, dimension (min(M,N))
+* The scalar factors of the elementary reflectors, as returned
+* by ZGERQF.
+*
+* WORK (workspace) COMPLEX*16 array, dimension (LWORK)
+*
+* LWORK (input) INTEGER
+* The dimension of the array WORK.
+*
+* RWORK (workspace) DOUBLE PRECISION array, dimension (max(M,N))
+*
+* RESULT (output) DOUBLE PRECISION array, dimension (2)
+* The test ratios:
+* RESULT(1) = norm( R - A*Q' ) / ( N * norm(A) * EPS )
+* RESULT(2) = norm( I - Q*Q' ) / ( N * 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, ZGERQF, ZHERK, ZLACPY, ZLASET, ZUNGRQ
+* ..
+* .. 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 = 'ZGERQF'
+ CALL ZGERQF( M, N, AF, LDA, TAU, WORK, LWORK, INFO )
+*
+* Copy details of Q
+*
+ CALL ZLASET( 'Full', N, N, ROGUE, ROGUE, Q, LDA )
+ IF( M.LE.N ) THEN
+ IF( M.GT.0 .AND. M.LT.N )
+ $ CALL ZLACPY( 'Full', M, N-M, AF, LDA, Q( N-M+1, 1 ), LDA )
+ IF( M.GT.1 )
+ $ CALL ZLACPY( 'Lower', M-1, M-1, AF( 2, N-M+1 ), LDA,
+ $ Q( N-M+2, N-M+1 ), LDA )
+ ELSE
+ IF( N.GT.1 )
+ $ CALL ZLACPY( 'Lower', N-1, N-1, AF( M-N+2, 1 ), LDA,
+ $ Q( 2, 1 ), LDA )
+ END IF
+*
+* Generate the n-by-n matrix Q
+*
+ SRNAMT = 'ZUNGRQ'
+ CALL ZUNGRQ( N, N, MINMN, Q, LDA, TAU, WORK, LWORK, INFO )
+*
+* Copy R
+*
+ CALL ZLASET( 'Full', M, N, DCMPLX( ZERO ), DCMPLX( ZERO ), R,
+ $ LDA )
+ IF( M.LE.N ) THEN
+ IF( M.GT.0 )
+ $ CALL ZLACPY( 'Upper', M, M, AF( 1, N-M+1 ), LDA,
+ $ R( 1, N-M+1 ), LDA )
+ ELSE
+ IF( M.GT.N .AND. N.GT.0 )
+ $ CALL ZLACPY( 'Full', M-N, N, AF, LDA, R, LDA )
+ IF( N.GT.0 )
+ $ CALL ZLACPY( 'Upper', N, N, AF( M-N+1, 1 ), LDA,
+ $ R( M-N+1, 1 ), LDA )
+ END IF
+*
+* Compute R - A*Q'
+*
+ CALL ZGEMM( 'No transpose', 'Conjugate transpose', M, N, N,
+ $ DCMPLX( -ONE ), A, LDA, Q, LDA, DCMPLX( ONE ), R,
+ $ LDA )
+*
+* Compute norm( R - Q'*A ) / ( N * 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, N ) ) ) / ANORM ) / EPS
+ ELSE
+ RESULT( 1 ) = ZERO
+ END IF
+*
+* Compute I - Q*Q'
+*
+ CALL ZLASET( 'Full', N, N, DCMPLX( ZERO ), DCMPLX( ONE ), R, LDA )
+ CALL ZHERK( 'Upper', 'No transpose', N, N, -ONE, Q, LDA, ONE, R,
+ $ LDA )
+*
+* Compute norm( I - Q*Q' ) / ( N * EPS ) .
+*
+ RESID = ZLANSY( '1', 'Upper', N, R, LDA, RWORK )
+*
+ RESULT( 2 ) = ( RESID / DBLE( MAX( 1, N ) ) ) / EPS
+*
+ RETURN
+*
+* End of ZRQT01
+*
+ END