263 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Fortran
		
	
	
	
			
		
		
	
	
			263 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Fortran
		
	
	
	
*> \brief \b CQRT03
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*
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*  =========== DOCUMENTATION ===========
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*
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* Online html documentation available at
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*            http://www.netlib.org/lapack/explore-html/
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*
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*  Definition:
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*  ===========
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*
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*       SUBROUTINE CQRT03( M, N, K, AF, C, CC, Q, LDA, TAU, WORK, LWORK,
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*                          RWORK, RESULT )
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*
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*       .. Scalar Arguments ..
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*       INTEGER            K, LDA, LWORK, M, N
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*       ..
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*       .. Array Arguments ..
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*       REAL               RESULT( * ), RWORK( * )
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*       COMPLEX            AF( LDA, * ), C( LDA, * ), CC( LDA, * ),
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*      $                   Q( LDA, * ), TAU( * ), WORK( LWORK )
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*       ..
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*
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*
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*> \par Purpose:
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*  =============
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*>
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*> \verbatim
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*>
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*> CQRT03 tests CUNMQR, which computes Q*C, Q'*C, C*Q or C*Q'.
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*>
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*> CQRT03 compares the results of a call to CUNMQR with the results of
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*> forming Q explicitly by a call to CUNGQR and then performing matrix
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*> multiplication by a call to CGEMM.
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*> \endverbatim
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*
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*  Arguments:
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*  ==========
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*
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*> \param[in] M
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*> \verbatim
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*>          M is INTEGER
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*>          The order of the orthogonal matrix Q.  M >= 0.
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*> \endverbatim
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*>
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*> \param[in] N
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*> \verbatim
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*>          N is INTEGER
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*>          The number of rows or columns of the matrix C; C is m-by-n if
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*>          Q is applied from the left, or n-by-m if Q is applied from
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*>          the right.  N >= 0.
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*> \endverbatim
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*>
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*> \param[in] K
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*> \verbatim
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*>          K is INTEGER
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*>          The number of elementary reflectors whose product defines the
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*>          orthogonal matrix Q.  M >= K >= 0.
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*> \endverbatim
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*>
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*> \param[in] AF
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*> \verbatim
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*>          AF is COMPLEX array, dimension (LDA,N)
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*>          Details of the QR factorization of an m-by-n matrix, as
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*>          returned by CGEQRF. See CGEQRF for further details.
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*> \endverbatim
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*>
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*> \param[out] C
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*> \verbatim
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*>          C is COMPLEX array, dimension (LDA,N)
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*> \endverbatim
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*>
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*> \param[out] CC
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*> \verbatim
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*>          CC is COMPLEX array, dimension (LDA,N)
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*> \endverbatim
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*>
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*> \param[out] Q
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*> \verbatim
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*>          Q is COMPLEX array, dimension (LDA,M)
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*> \endverbatim
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*>
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*> \param[in] LDA
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*> \verbatim
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*>          LDA is INTEGER
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*>          The leading dimension of the arrays AF, C, CC, and Q.
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*> \endverbatim
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*>
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*> \param[in] TAU
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*> \verbatim
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*>          TAU is COMPLEX array, dimension (min(M,N))
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*>          The scalar factors of the elementary reflectors corresponding
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*>          to the QR factorization in AF.
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*> \endverbatim
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*>
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*> \param[out] WORK
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*> \verbatim
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*>          WORK is COMPLEX array, dimension (LWORK)
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*> \endverbatim
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*>
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*> \param[in] LWORK
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*> \verbatim
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*>          LWORK is INTEGER
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*>          The length of WORK.  LWORK must be at least M, and should be
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*>          M*NB, where NB is the blocksize for this environment.
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*> \endverbatim
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*>
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*> \param[out] RWORK
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*> \verbatim
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*>          RWORK is REAL array, dimension (M)
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*> \endverbatim
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*>
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*> \param[out] RESULT
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*> \verbatim
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*>          RESULT is REAL array, dimension (4)
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*>          The test ratios compare two techniques for multiplying a
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*>          random matrix C by an m-by-m orthogonal matrix Q.
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*>          RESULT(1) = norm( Q*C - Q*C )  / ( M * norm(C) * EPS )
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*>          RESULT(2) = norm( C*Q - C*Q )  / ( M * norm(C) * EPS )
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*>          RESULT(3) = norm( Q'*C - Q'*C )/ ( M * norm(C) * EPS )
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*>          RESULT(4) = norm( C*Q' - C*Q' )/ ( M * norm(C) * EPS )
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*> \endverbatim
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*
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*  Authors:
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*  ========
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*
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*> \author Univ. of Tennessee
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*> \author Univ. of California Berkeley
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*> \author Univ. of Colorado Denver
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*> \author NAG Ltd.
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*
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*> \ingroup complex_lin
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*
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*  =====================================================================
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      SUBROUTINE CQRT03( M, N, K, AF, C, CC, Q, LDA, TAU, WORK, LWORK,
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     $                   RWORK, RESULT )
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*
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*  -- LAPACK test routine --
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*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
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*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
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*
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*     .. Scalar Arguments ..
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      INTEGER            K, LDA, LWORK, M, N
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*     ..
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*     .. Array Arguments ..
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      REAL               RESULT( * ), RWORK( * )
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      COMPLEX            AF( LDA, * ), C( LDA, * ), CC( LDA, * ),
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     $                   Q( LDA, * ), TAU( * ), WORK( LWORK )
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*     ..
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*
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*  =====================================================================
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*
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*     .. Parameters ..
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      REAL               ZERO, ONE
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      PARAMETER          ( ZERO = 0.0E+0, ONE = 1.0E+0 )
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      COMPLEX            ROGUE
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      PARAMETER          ( ROGUE = ( -1.0E+10, -1.0E+10 ) )
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*     ..
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*     .. Local Scalars ..
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      CHARACTER          SIDE, TRANS
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      INTEGER            INFO, ISIDE, ITRANS, J, MC, NC
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      REAL               CNORM, EPS, RESID
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*     ..
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*     .. External Functions ..
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      LOGICAL            LSAME
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      REAL               CLANGE, SLAMCH
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      EXTERNAL           LSAME, CLANGE, SLAMCH
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*     ..
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*     .. External Subroutines ..
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      EXTERNAL           CGEMM, CLACPY, CLARNV, CLASET, CUNGQR, CUNMQR
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*     ..
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*     .. Local Arrays ..
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      INTEGER            ISEED( 4 )
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*     ..
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*     .. Intrinsic Functions ..
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      INTRINSIC          CMPLX, MAX, REAL
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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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*     .. Data statements ..
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      DATA               ISEED / 1988, 1989, 1990, 1991 /
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*     ..
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*     .. Executable Statements ..
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*
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      EPS = SLAMCH( 'Epsilon' )
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*
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*     Copy the first k columns of the factorization to the array Q
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*
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      CALL CLASET( 'Full', M, M, ROGUE, ROGUE, Q, LDA )
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      CALL CLACPY( 'Lower', M-1, K, 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 = 'CUNGQR'
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      CALL CUNGQR( M, M, K, Q, LDA, TAU, WORK, LWORK, INFO )
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*
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      DO 30 ISIDE = 1, 2
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         IF( ISIDE.EQ.1 ) THEN
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            SIDE = 'L'
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            MC = M
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            NC = N
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         ELSE
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            SIDE = 'R'
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            MC = N
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            NC = M
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         END IF
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*
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*        Generate MC by NC matrix C
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*
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         DO 10 J = 1, NC
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            CALL CLARNV( 2, ISEED, MC, C( 1, J ) )
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   10    CONTINUE
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         CNORM = CLANGE( '1', MC, NC, C, LDA, RWORK )
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         IF( CNORM.EQ.ZERO )
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     $      CNORM = ONE
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*
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         DO 20 ITRANS = 1, 2
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            IF( ITRANS.EQ.1 ) THEN
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               TRANS = 'N'
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            ELSE
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               TRANS = 'C'
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            END IF
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*
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*           Copy C
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*
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            CALL CLACPY( 'Full', MC, NC, C, LDA, CC, LDA )
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*
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*           Apply Q or Q' to C
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*
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            SRNAMT = 'CUNMQR'
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            CALL CUNMQR( SIDE, TRANS, MC, NC, K, AF, LDA, TAU, CC, LDA,
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     $                   WORK, LWORK, INFO )
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*
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*           Form explicit product and subtract
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*
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            IF( LSAME( SIDE, 'L' ) ) THEN
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               CALL CGEMM( TRANS, 'No transpose', MC, NC, MC,
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     $                     CMPLX( -ONE ), Q, LDA, C, LDA, CMPLX( ONE ),
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     $                     CC, LDA )
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            ELSE
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               CALL CGEMM( 'No transpose', TRANS, MC, NC, NC,
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     $                     CMPLX( -ONE ), C, LDA, Q, LDA, CMPLX( ONE ),
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     $                     CC, LDA )
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            END IF
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*
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*           Compute error in the difference
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*
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            RESID = CLANGE( '1', MC, NC, CC, LDA, RWORK )
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            RESULT( ( ISIDE-1 )*2+ITRANS ) = RESID /
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     $         ( REAL( MAX( 1, M ) )*CNORM*EPS )
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*
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   20    CONTINUE
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   30 CONTINUE
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*
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      RETURN
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*
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*     End of CQRT03
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*
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      END
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