712 lines
		
	
	
		
			25 KiB
		
	
	
	
		
			Fortran
		
	
	
	
			
		
		
	
	
			712 lines
		
	
	
		
			25 KiB
		
	
	
	
		
			Fortran
		
	
	
	
*> \brief \b SORCSD2BY1
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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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*> \htmlonly
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*> Download SORCSD2BY1 + dependencies
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/sorcsd2by1.f">
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*> [TGZ]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/sorcsd2by1.f">
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*> [ZIP]</a>
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/sorcsd2by1.f">
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*> [TXT]</a>
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*> \endhtmlonly
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*
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*  Definition:
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*  ===========
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*
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*       SUBROUTINE SORCSD2BY1( JOBU1, JOBU2, JOBV1T, M, P, Q, X11, LDX11,
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*                              X21, LDX21, THETA, U1, LDU1, U2, LDU2, V1T,
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*                              LDV1T, WORK, LWORK, IWORK, INFO )
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* 
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*       .. Scalar Arguments ..
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*       CHARACTER          JOBU1, JOBU2, JOBV1T
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*       INTEGER            INFO, LDU1, LDU2, LDV1T, LWORK, LDX11, LDX21,
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*      $                   M, P, Q
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*       ..
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*       .. Array Arguments ..
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*       REAL               THETA(*)
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*       REAL               U1(LDU1,*), U2(LDU2,*), V1T(LDV1T,*), WORK(*),
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*      $                   X11(LDX11,*), X21(LDX21,*)
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*       INTEGER            IWORK(*)
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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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*> SORCSD2BY1 computes the CS decomposition of an M-by-Q matrix X with
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*> orthonormal columns that has been partitioned into a 2-by-1 block
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*> structure:
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*>
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*>                                [  I  0  0 ]
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*>                                [  0  C  0 ]
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*>          [ X11 ]   [ U1 |    ] [  0  0  0 ]
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*>      X = [-----] = [---------] [----------] V1**T .
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*>          [ X21 ]   [    | U2 ] [  0  0  0 ]
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*>                                [  0  S  0 ]
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*>                                [  0  0  I ]
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*> 
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*> X11 is P-by-Q. The orthogonal matrices U1, U2, V1, and V2 are P-by-P,
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*> (M-P)-by-(M-P), Q-by-Q, and (M-Q)-by-(M-Q), respectively. C and S are
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*> R-by-R nonnegative diagonal matrices satisfying C^2 + S^2 = I, in
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*> which R = MIN(P,M-P,Q,M-Q).
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*>
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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] JOBU1
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*> \verbatim
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*>          JOBU1 is CHARACTER
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*>           = 'Y':      U1 is computed;
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*>           otherwise:  U1 is not computed.
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*> \endverbatim
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*>
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*> \param[in] JOBU2
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*> \verbatim
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*>          JOBU2 is CHARACTER
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*>           = 'Y':      U2 is computed;
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*>           otherwise:  U2 is not computed.
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*> \endverbatim
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*>
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*> \param[in] JOBV1T
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*> \verbatim
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*>          JOBV1T is CHARACTER
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*>           = 'Y':      V1T is computed;
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*>           otherwise:  V1T is not computed.
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*> \endverbatim
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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 number of rows and columns in X.
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*> \endverbatim
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*>
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*> \param[in] P
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*> \verbatim
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*>          P is INTEGER
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*>           The number of rows in X11 and X12. 0 <= P <= M.
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*> \endverbatim
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*>
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*> \param[in] Q
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*> \verbatim
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*>          Q is INTEGER
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*>           The number of columns in X11 and X21. 0 <= Q <= M.
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*> \endverbatim
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*>
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*> \param[in,out] X11
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*> \verbatim
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*>          X11 is REAL array, dimension (LDX11,Q)
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*>           On entry, part of the orthogonal matrix whose CSD is
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*>           desired.
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*> \endverbatim
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*>
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*> \param[in] LDX11
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*> \verbatim
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*>          LDX11 is INTEGER
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*>           The leading dimension of X11. LDX11 >= MAX(1,P).
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*> \endverbatim
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*>
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*> \param[in,out] X21
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*> \verbatim
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*>          X21 is REAL array, dimension (LDX21,Q)
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*>           On entry, part of the orthogonal matrix whose CSD is
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*>           desired.
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*> \endverbatim
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*>
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*> \param[in] LDX21
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*> \verbatim
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*>          LDX21 is INTEGER
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*>           The leading dimension of X21. LDX21 >= MAX(1,M-P).
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*> \endverbatim
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*>
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*> \param[out] THETA
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*> \verbatim
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*>          THETA is REAL array, dimension (R), in which R =
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*>           MIN(P,M-P,Q,M-Q).
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*>           C = DIAG( COS(THETA(1)), ... , COS(THETA(R)) ) and
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*>           S = DIAG( SIN(THETA(1)), ... , SIN(THETA(R)) ).
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*> \endverbatim
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*>
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*> \param[out] U1
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*> \verbatim
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*>          U1 is REAL array, dimension (P)
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*>           If JOBU1 = 'Y', U1 contains the P-by-P orthogonal matrix U1.
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*> \endverbatim
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*>
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*> \param[in] LDU1
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*> \verbatim
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*>          LDU1 is INTEGER
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*>           The leading dimension of U1. If JOBU1 = 'Y', LDU1 >=
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*>           MAX(1,P).
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*> \endverbatim
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*>
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*> \param[out] U2
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*> \verbatim
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*>          U2 is REAL array, dimension (M-P)
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*>           If JOBU2 = 'Y', U2 contains the (M-P)-by-(M-P) orthogonal
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*>           matrix U2.
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*> \endverbatim
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*>
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*> \param[in] LDU2
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*> \verbatim
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*>          LDU2 is INTEGER
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*>           The leading dimension of U2. If JOBU2 = 'Y', LDU2 >=
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*>           MAX(1,M-P).
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*> \endverbatim
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*>
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*> \param[out] V1T
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*> \verbatim
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*>          V1T is REAL array, dimension (Q)
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*>           If JOBV1T = 'Y', V1T contains the Q-by-Q matrix orthogonal
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*>           matrix V1**T.
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*> \endverbatim
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*>
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*> \param[in] LDV1T
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*> \verbatim
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*>          LDV1T is INTEGER
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*>           The leading dimension of V1T. If JOBV1T = 'Y', LDV1T >=
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*>           MAX(1,Q).
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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 REAL array, dimension (MAX(1,LWORK))
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*>           On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
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*>           If INFO > 0 on exit, WORK(2:R) contains the values PHI(1),
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*>           ..., PHI(R-1) that, together with THETA(1), ..., THETA(R),
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*>           define the matrix in intermediate bidiagonal-block form
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*>           remaining after nonconvergence. INFO specifies the number
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*>           of nonzero PHI's.
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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 dimension of the array WORK.
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*> \endverbatim
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*>
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*>           If LWORK = -1, then a workspace query is assumed; the routine
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*>           only calculates the optimal size of the WORK array, returns
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*>           this value as the first entry of the work array, and no error
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*>           message related to LWORK is issued by XERBLA.
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*> \param[out] IWORK
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*> \verbatim
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*>          IWORK is INTEGER array, dimension (M-MIN(P,M-P,Q,M-Q))
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*> \endverbatim
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*>
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*> \param[out] INFO
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*> \verbatim
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*>          INFO is INTEGER
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*>           = 0:  successful exit.
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*>           < 0:  if INFO = -i, the i-th argument had an illegal value.
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*>           > 0:  SBBCSD did not converge. See the description of WORK
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*>                above for details.
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*> \endverbatim
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*>
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*>  \par Reference:
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*   ===============
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*>  [1] Brian D. Sutton. Computing the complete CS decomposition. Numer.
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*>      Algorithms, 50(1):33-65, 2009.
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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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*> \date July 2012
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*
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*> \ingroup realOTHERcomputational
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*
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*  =====================================================================
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      SUBROUTINE SORCSD2BY1( JOBU1, JOBU2, JOBV1T, M, P, Q, X11, LDX11,
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     $                       X21, LDX21, THETA, U1, LDU1, U2, LDU2, V1T,
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     $                       LDV1T, WORK, LWORK, IWORK, INFO )
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*
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*  -- LAPACK computational routine (version 3.5.0) --
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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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*     July 2012
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*
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*     .. Scalar Arguments ..
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      CHARACTER          JOBU1, JOBU2, JOBV1T
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      INTEGER            INFO, LDU1, LDU2, LDV1T, LWORK, LDX11, LDX21,
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     $                   M, P, Q
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*     ..
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*     .. Array Arguments ..
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      REAL               THETA(*)
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      REAL               U1(LDU1,*), U2(LDU2,*), V1T(LDV1T,*), WORK(*),
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     $                   X11(LDX11,*), X21(LDX21,*)
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      INTEGER            IWORK(*)
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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               ONE, ZERO
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      PARAMETER          ( ONE = 1.0E0, ZERO = 0.0E0 )
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*     ..
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*     .. Local Scalars ..
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      INTEGER            CHILDINFO, I, IB11D, IB11E, IB12D, IB12E,
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     $                   IB21D, IB21E, IB22D, IB22E, IBBCSD, IORBDB,
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     $                   IORGLQ, IORGQR, IPHI, ITAUP1, ITAUP2, ITAUQ1,
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     $                   J, LBBCSD, LORBDB, LORGLQ, LORGLQMIN,
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     $                   LORGLQOPT, LORGQR, LORGQRMIN, LORGQROPT,
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     $                   LWORKMIN, LWORKOPT, R
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      LOGICAL            LQUERY, WANTU1, WANTU2, WANTV1T
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*     ..
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*     .. External Subroutines ..
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      EXTERNAL           SBBCSD, SCOPY, SLACPY, SLAPMR, SLAPMT, SORBDB1,
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     $                   SORBDB2, SORBDB3, SORBDB4, SORGLQ, SORGQR,
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     $                   XERBLA
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*     ..
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*     .. External Functions ..
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      LOGICAL            LSAME
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      EXTERNAL           LSAME
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*     ..
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*     .. Intrinsic Function ..
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      INTRINSIC          INT, MAX, MIN
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*     ..
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*     .. Executable Statements ..
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*
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*     Test input arguments
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*
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      INFO = 0
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      WANTU1 = LSAME( JOBU1, 'Y' )
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      WANTU2 = LSAME( JOBU2, 'Y' )
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      WANTV1T = LSAME( JOBV1T, 'Y' )
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      LQUERY = LWORK .EQ. -1
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*
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      IF( M .LT. 0 ) THEN
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         INFO = -4
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      ELSE IF( P .LT. 0 .OR. P .GT. M ) THEN
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         INFO = -5
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      ELSE IF( Q .LT. 0 .OR. Q .GT. M ) THEN
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         INFO = -6
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      ELSE IF( LDX11 .LT. MAX( 1, P ) ) THEN
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         INFO = -8
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      ELSE IF( LDX21 .LT. MAX( 1, M-P ) ) THEN
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         INFO = -10
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      ELSE IF( WANTU1 .AND. LDU1 .LT. P ) THEN
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         INFO = -13
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      ELSE IF( WANTU2 .AND. LDU2 .LT. M - P ) THEN
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         INFO = -15
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      ELSE IF( WANTV1T .AND. LDV1T .LT. Q ) THEN
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         INFO = -17
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      END IF
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*
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      R = MIN( P, M-P, Q, M-Q )
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*
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*     Compute workspace
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*
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*       WORK layout:
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*     |-------------------------------------------------------|
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*     | LWORKOPT (1)                                          |
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*     |-------------------------------------------------------|
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*     | PHI (MAX(1,R-1))                                      |
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*     |-------------------------------------------------------|
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*     | TAUP1 (MAX(1,P))                        | B11D (R)    |
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*     | TAUP2 (MAX(1,M-P))                      | B11E (R-1)  |
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*     | TAUQ1 (MAX(1,Q))                        | B12D (R)    |
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*     |-----------------------------------------| B12E (R-1)  |
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*     | SORBDB WORK | SORGQR WORK | SORGLQ WORK | B21D (R)    |
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*     |             |             |             | B21E (R-1)  |
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*     |             |             |             | B22D (R)    |
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*     |             |             |             | B22E (R-1)  |
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*     |             |             |             | SBBCSD WORK |
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*     |-------------------------------------------------------|
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*
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      IF( INFO .EQ. 0 ) THEN
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         IPHI = 2
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         IB11D = IPHI + MAX( 1, R-1 )
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         IB11E = IB11D + MAX( 1, R )
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         IB12D = IB11E + MAX( 1, R - 1 )
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         IB12E = IB12D + MAX( 1, R )
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         IB21D = IB12E + MAX( 1, R - 1 )
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         IB21E = IB21D + MAX( 1, R )
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         IB22D = IB21E + MAX( 1, R - 1 )
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         IB22E = IB22D + MAX( 1, R )
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         IBBCSD = IB22E + MAX( 1, R - 1 )
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         ITAUP1 = IPHI + MAX( 1, R-1 )
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         ITAUP2 = ITAUP1 + MAX( 1, P )
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         ITAUQ1 = ITAUP2 + MAX( 1, M-P )
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         IORBDB = ITAUQ1 + MAX( 1, Q )
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         IORGQR = ITAUQ1 + MAX( 1, Q )
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         IORGLQ = ITAUQ1 + MAX( 1, Q )
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         IF( R .EQ. Q ) THEN
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            CALL SORBDB1( M, P, Q, X11, LDX11, X21, LDX21, THETA, 0, 0,
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     $                    0, 0, WORK, -1, CHILDINFO )
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            LORBDB = INT( WORK(1) )
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            IF( P .GE. M-P ) THEN
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               CALL SORGQR( P, P, Q, U1, LDU1, 0, WORK(1), -1,
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     $                      CHILDINFO )
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               LORGQRMIN = MAX( 1, P )
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               LORGQROPT = INT( WORK(1) )
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            ELSE
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               CALL SORGQR( M-P, M-P, Q, U2, LDU2, 0, WORK(1), -1,
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     $                      CHILDINFO )
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               LORGQRMIN = MAX( 1, M-P )
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               LORGQROPT = INT( WORK(1) )
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            END IF
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            CALL SORGLQ( MAX(0,Q-1), MAX(0,Q-1), MAX(0,Q-1), V1T, LDV1T,
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     $                   0, WORK(1), -1, CHILDINFO )
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            LORGLQMIN = MAX( 1, Q-1 )
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            LORGLQOPT = INT( WORK(1) )
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            CALL SBBCSD( JOBU1, JOBU2, JOBV1T, 'N', 'N', M, P, Q, THETA,
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     $                   0, U1, LDU1, U2, LDU2, V1T, LDV1T, 0, 1, 0, 0,
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     $                   0, 0, 0, 0, 0, 0, WORK(1), -1, CHILDINFO )
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            LBBCSD = INT( WORK(1) )
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         ELSE IF( R .EQ. P ) THEN
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            CALL SORBDB2( M, P, Q, X11, LDX11, X21, LDX21, THETA, 0, 0,
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     $                    0, 0, WORK(1), -1, CHILDINFO )
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            LORBDB = INT( WORK(1) )
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            IF( P-1 .GE. M-P ) THEN
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               CALL SORGQR( P-1, P-1, P-1, U1(2,2), LDU1, 0, WORK(1),
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     $                      -1, CHILDINFO )
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               LORGQRMIN = MAX( 1, P-1 )
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               LORGQROPT = INT( WORK(1) )
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            ELSE
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               CALL SORGQR( M-P, M-P, Q, U2, LDU2, 0, WORK(1), -1,
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     $                      CHILDINFO )
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               LORGQRMIN = MAX( 1, M-P )
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               LORGQROPT = INT( WORK(1) )
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            END IF
 | 
						|
            CALL SORGLQ( Q, Q, R, V1T, LDV1T, 0, WORK(1), -1,
 | 
						|
     $                   CHILDINFO )
 | 
						|
            LORGLQMIN = MAX( 1, Q )
 | 
						|
            LORGLQOPT = INT( WORK(1) )
 | 
						|
            CALL SBBCSD( JOBV1T, 'N', JOBU1, JOBU2, 'T', M, Q, P, THETA,
 | 
						|
     $                   0, V1T, LDV1T, 0, 1, U1, LDU1, U2, LDU2, 0, 0,
 | 
						|
     $                   0, 0, 0, 0, 0, 0, WORK(1), -1, CHILDINFO )
 | 
						|
            LBBCSD = INT( WORK(1) )
 | 
						|
         ELSE IF( R .EQ. M-P ) THEN
 | 
						|
            CALL SORBDB3( M, P, Q, X11, LDX11, X21, LDX21, THETA, 0, 0,
 | 
						|
     $                    0, 0, WORK(1), -1, CHILDINFO )
 | 
						|
            LORBDB = INT( WORK(1) )
 | 
						|
            IF( P .GE. M-P-1 ) THEN
 | 
						|
               CALL SORGQR( P, P, Q, U1, LDU1, 0, WORK(1), -1,
 | 
						|
     $                      CHILDINFO )
 | 
						|
               LORGQRMIN = MAX( 1, P )
 | 
						|
               LORGQROPT = INT( WORK(1) )
 | 
						|
            ELSE
 | 
						|
               CALL SORGQR( M-P-1, M-P-1, M-P-1, U2(2,2), LDU2, 0,
 | 
						|
     $                      WORK(1), -1, CHILDINFO )
 | 
						|
               LORGQRMIN = MAX( 1, M-P-1 )
 | 
						|
               LORGQROPT = INT( WORK(1) )
 | 
						|
            END IF
 | 
						|
            CALL SORGLQ( Q, Q, R, V1T, LDV1T, 0, WORK(1), -1,
 | 
						|
     $                   CHILDINFO )
 | 
						|
            LORGLQMIN = MAX( 1, Q )
 | 
						|
            LORGLQOPT = INT( WORK(1) )
 | 
						|
            CALL SBBCSD( 'N', JOBV1T, JOBU2, JOBU1, 'T', M, M-Q, M-P,
 | 
						|
     $                   THETA, 0, 0, 1, V1T, LDV1T, U2, LDU2, U1, LDU1,
 | 
						|
     $                   0, 0, 0, 0, 0, 0, 0, 0, WORK(1), -1,
 | 
						|
     $                   CHILDINFO )
 | 
						|
            LBBCSD = INT( WORK(1) )
 | 
						|
         ELSE
 | 
						|
            CALL SORBDB4( M, P, Q, X11, LDX11, X21, LDX21, THETA, 0, 0,
 | 
						|
     $                    0, 0, 0, WORK(1), -1, CHILDINFO )
 | 
						|
            LORBDB = M + INT( WORK(1) )
 | 
						|
            IF( P .GE. M-P ) THEN
 | 
						|
               CALL SORGQR( P, P, M-Q, U1, LDU1, 0, WORK(1), -1,
 | 
						|
     $                      CHILDINFO )
 | 
						|
               LORGQRMIN = MAX( 1, P )
 | 
						|
               LORGQROPT = INT( WORK(1) )
 | 
						|
            ELSE
 | 
						|
               CALL SORGQR( M-P, M-P, M-Q, U2, LDU2, 0, WORK(1), -1,
 | 
						|
     $                      CHILDINFO )
 | 
						|
               LORGQRMIN = MAX( 1, M-P )
 | 
						|
               LORGQROPT = INT( WORK(1) )
 | 
						|
            END IF
 | 
						|
            CALL SORGLQ( Q, Q, Q, V1T, LDV1T, 0, WORK(1), -1,
 | 
						|
     $                   CHILDINFO )
 | 
						|
            LORGLQMIN = MAX( 1, Q )
 | 
						|
            LORGLQOPT = INT( WORK(1) )
 | 
						|
            CALL SBBCSD( JOBU2, JOBU1, 'N', JOBV1T, 'N', M, M-P, M-Q,
 | 
						|
     $                   THETA, 0, U2, LDU2, U1, LDU1, 0, 1, V1T, LDV1T,
 | 
						|
     $                   0, 0, 0, 0, 0, 0, 0, 0, WORK(1), -1,
 | 
						|
     $                   CHILDINFO )
 | 
						|
            LBBCSD = INT( WORK(1) )
 | 
						|
         END IF
 | 
						|
         LWORKMIN = MAX( IORBDB+LORBDB-1,
 | 
						|
     $                   IORGQR+LORGQRMIN-1,
 | 
						|
     $                   IORGLQ+LORGLQMIN-1,
 | 
						|
     $                   IBBCSD+LBBCSD-1 )
 | 
						|
         LWORKOPT = MAX( IORBDB+LORBDB-1,
 | 
						|
     $                   IORGQR+LORGQROPT-1,
 | 
						|
     $                   IORGLQ+LORGLQOPT-1,
 | 
						|
     $                   IBBCSD+LBBCSD-1 )
 | 
						|
         WORK(1) = LWORKOPT
 | 
						|
         IF( LWORK .LT. LWORKMIN .AND. .NOT.LQUERY ) THEN
 | 
						|
            INFO = -19
 | 
						|
         END IF
 | 
						|
      END IF
 | 
						|
      IF( INFO .NE. 0 ) THEN
 | 
						|
         CALL XERBLA( 'SORCSD2BY1', -INFO )
 | 
						|
         RETURN
 | 
						|
      ELSE IF( LQUERY ) THEN
 | 
						|
         RETURN
 | 
						|
      END IF
 | 
						|
      LORGQR = LWORK-IORGQR+1
 | 
						|
      LORGLQ = LWORK-IORGLQ+1
 | 
						|
*
 | 
						|
*     Handle four cases separately: R = Q, R = P, R = M-P, and R = M-Q,
 | 
						|
*     in which R = MIN(P,M-P,Q,M-Q)
 | 
						|
*
 | 
						|
      IF( R .EQ. Q ) THEN
 | 
						|
*
 | 
						|
*        Case 1: R = Q
 | 
						|
*
 | 
						|
*        Simultaneously bidiagonalize X11 and X21
 | 
						|
*
 | 
						|
         CALL SORBDB1( M, P, Q, X11, LDX11, X21, LDX21, THETA,
 | 
						|
     $                 WORK(IPHI), WORK(ITAUP1), WORK(ITAUP2),
 | 
						|
     $                 WORK(ITAUQ1), WORK(IORBDB), LORBDB, CHILDINFO )
 | 
						|
*
 | 
						|
*        Accumulate Householder reflectors
 | 
						|
*
 | 
						|
         IF( WANTU1 .AND. P .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'L', P, Q, X11, LDX11, U1, LDU1 )
 | 
						|
            CALL SORGQR( P, P, Q, U1, LDU1, WORK(ITAUP1), WORK(IORGQR),
 | 
						|
     $                   LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTU2 .AND. M-P .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'L', M-P, Q, X21, LDX21, U2, LDU2 )
 | 
						|
            CALL SORGQR( M-P, M-P, Q, U2, LDU2, WORK(ITAUP2),
 | 
						|
     $                   WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTV1T .AND. Q .GT. 0 ) THEN
 | 
						|
            V1T(1,1) = ONE
 | 
						|
            DO J = 2, Q
 | 
						|
               V1T(1,J) = ZERO
 | 
						|
               V1T(J,1) = ZERO
 | 
						|
            END DO
 | 
						|
            CALL SLACPY( 'U', Q-1, Q-1, X21(1,2), LDX21, V1T(2,2),
 | 
						|
     $                   LDV1T )
 | 
						|
            CALL SORGLQ( Q-1, Q-1, Q-1, V1T(2,2), LDV1T, WORK(ITAUQ1),
 | 
						|
     $                   WORK(IORGLQ), LORGLQ, CHILDINFO )
 | 
						|
         END IF
 | 
						|
*   
 | 
						|
*        Simultaneously diagonalize X11 and X21.
 | 
						|
*   
 | 
						|
         CALL SBBCSD( JOBU1, JOBU2, JOBV1T, 'N', 'N', M, P, Q, THETA,
 | 
						|
     $                WORK(IPHI), U1, LDU1, U2, LDU2, V1T, LDV1T, 0, 1,
 | 
						|
     $                WORK(IB11D), WORK(IB11E), WORK(IB12D),
 | 
						|
     $                WORK(IB12E), WORK(IB21D), WORK(IB21E),
 | 
						|
     $                WORK(IB22D), WORK(IB22E), WORK(IBBCSD), LBBCSD,
 | 
						|
     $                CHILDINFO )
 | 
						|
*   
 | 
						|
*        Permute rows and columns to place zero submatrices in
 | 
						|
*        preferred positions
 | 
						|
*
 | 
						|
         IF( Q .GT. 0 .AND. WANTU2 ) THEN
 | 
						|
            DO I = 1, Q
 | 
						|
               IWORK(I) = M - P - Q + I
 | 
						|
            END DO
 | 
						|
            DO I = Q + 1, M - P
 | 
						|
               IWORK(I) = I - Q
 | 
						|
            END DO
 | 
						|
            CALL SLAPMT( .FALSE., M-P, M-P, U2, LDU2, IWORK )
 | 
						|
         END IF
 | 
						|
      ELSE IF( R .EQ. P ) THEN
 | 
						|
*
 | 
						|
*        Case 2: R = P
 | 
						|
*
 | 
						|
*        Simultaneously bidiagonalize X11 and X21
 | 
						|
*
 | 
						|
         CALL SORBDB2( M, P, Q, X11, LDX11, X21, LDX21, THETA,
 | 
						|
     $                 WORK(IPHI), WORK(ITAUP1), WORK(ITAUP2),
 | 
						|
     $                 WORK(ITAUQ1), WORK(IORBDB), LORBDB, CHILDINFO )
 | 
						|
*
 | 
						|
*        Accumulate Householder reflectors
 | 
						|
*
 | 
						|
         IF( WANTU1 .AND. P .GT. 0 ) THEN
 | 
						|
            U1(1,1) = ONE
 | 
						|
            DO J = 2, P
 | 
						|
               U1(1,J) = ZERO
 | 
						|
               U1(J,1) = ZERO
 | 
						|
            END DO
 | 
						|
            CALL SLACPY( 'L', P-1, P-1, X11(2,1), LDX11, U1(2,2), LDU1 )
 | 
						|
            CALL SORGQR( P-1, P-1, P-1, U1(2,2), LDU1, WORK(ITAUP1),
 | 
						|
     $                   WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTU2 .AND. M-P .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'L', M-P, Q, X21, LDX21, U2, LDU2 )
 | 
						|
            CALL SORGQR( M-P, M-P, Q, U2, LDU2, WORK(ITAUP2),
 | 
						|
     $                   WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTV1T .AND. Q .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'U', P, Q, X11, LDX11, V1T, LDV1T )
 | 
						|
            CALL SORGLQ( Q, Q, R, V1T, LDV1T, WORK(ITAUQ1),
 | 
						|
     $                   WORK(IORGLQ), LORGLQ, CHILDINFO )
 | 
						|
         END IF
 | 
						|
*   
 | 
						|
*        Simultaneously diagonalize X11 and X21.
 | 
						|
*   
 | 
						|
         CALL SBBCSD( JOBV1T, 'N', JOBU1, JOBU2, 'T', M, Q, P, THETA,
 | 
						|
     $                WORK(IPHI), V1T, LDV1T, 0, 1, U1, LDU1, U2, LDU2,
 | 
						|
     $                WORK(IB11D), WORK(IB11E), WORK(IB12D),
 | 
						|
     $                WORK(IB12E), WORK(IB21D), WORK(IB21E),
 | 
						|
     $                WORK(IB22D), WORK(IB22E), WORK(IBBCSD), LBBCSD,
 | 
						|
     $                CHILDINFO )
 | 
						|
*   
 | 
						|
*        Permute rows and columns to place identity submatrices in
 | 
						|
*        preferred positions
 | 
						|
*
 | 
						|
         IF( Q .GT. 0 .AND. WANTU2 ) THEN
 | 
						|
            DO I = 1, Q
 | 
						|
               IWORK(I) = M - P - Q + I
 | 
						|
            END DO
 | 
						|
            DO I = Q + 1, M - P
 | 
						|
               IWORK(I) = I - Q
 | 
						|
            END DO
 | 
						|
            CALL SLAPMT( .FALSE., M-P, M-P, U2, LDU2, IWORK )
 | 
						|
         END IF
 | 
						|
      ELSE IF( R .EQ. M-P ) THEN
 | 
						|
*
 | 
						|
*        Case 3: R = M-P
 | 
						|
*
 | 
						|
*        Simultaneously bidiagonalize X11 and X21
 | 
						|
*
 | 
						|
         CALL SORBDB3( M, P, Q, X11, LDX11, X21, LDX21, THETA,
 | 
						|
     $                 WORK(IPHI), WORK(ITAUP1), WORK(ITAUP2),
 | 
						|
     $                 WORK(ITAUQ1), WORK(IORBDB), LORBDB, CHILDINFO )
 | 
						|
*
 | 
						|
*        Accumulate Householder reflectors
 | 
						|
*
 | 
						|
         IF( WANTU1 .AND. P .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'L', P, Q, X11, LDX11, U1, LDU1 )
 | 
						|
            CALL SORGQR( P, P, Q, U1, LDU1, WORK(ITAUP1), WORK(IORGQR),
 | 
						|
     $                   LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTU2 .AND. M-P .GT. 0 ) THEN
 | 
						|
            U2(1,1) = ONE
 | 
						|
            DO J = 2, M-P
 | 
						|
               U2(1,J) = ZERO
 | 
						|
               U2(J,1) = ZERO
 | 
						|
            END DO
 | 
						|
            CALL SLACPY( 'L', M-P-1, M-P-1, X21(2,1), LDX21, U2(2,2),
 | 
						|
     $                   LDU2 )
 | 
						|
            CALL SORGQR( M-P-1, M-P-1, M-P-1, U2(2,2), LDU2,
 | 
						|
     $                   WORK(ITAUP2), WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTV1T .AND. Q .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'U', M-P, Q, X21, LDX21, V1T, LDV1T )
 | 
						|
            CALL SORGLQ( Q, Q, R, V1T, LDV1T, WORK(ITAUQ1),
 | 
						|
     $                   WORK(IORGLQ), LORGLQ, CHILDINFO )
 | 
						|
         END IF
 | 
						|
*   
 | 
						|
*        Simultaneously diagonalize X11 and X21.
 | 
						|
*   
 | 
						|
         CALL SBBCSD( 'N', JOBV1T, JOBU2, JOBU1, 'T', M, M-Q, M-P,
 | 
						|
     $                THETA, WORK(IPHI), 0, 1, V1T, LDV1T, U2, LDU2, U1,
 | 
						|
     $                LDU1, WORK(IB11D), WORK(IB11E), WORK(IB12D),
 | 
						|
     $                WORK(IB12E), WORK(IB21D), WORK(IB21E),
 | 
						|
     $                WORK(IB22D), WORK(IB22E), WORK(IBBCSD), LBBCSD,
 | 
						|
     $                CHILDINFO )
 | 
						|
*   
 | 
						|
*        Permute rows and columns to place identity submatrices in
 | 
						|
*        preferred positions
 | 
						|
*
 | 
						|
         IF( Q .GT. R ) THEN
 | 
						|
            DO I = 1, R
 | 
						|
               IWORK(I) = Q - R + I
 | 
						|
            END DO
 | 
						|
            DO I = R + 1, Q
 | 
						|
               IWORK(I) = I - R
 | 
						|
            END DO
 | 
						|
            IF( WANTU1 ) THEN
 | 
						|
               CALL SLAPMT( .FALSE., P, Q, U1, LDU1, IWORK )
 | 
						|
            END IF
 | 
						|
            IF( WANTV1T ) THEN
 | 
						|
               CALL SLAPMR( .FALSE., Q, Q, V1T, LDV1T, IWORK )
 | 
						|
            END IF
 | 
						|
         END IF
 | 
						|
      ELSE
 | 
						|
*
 | 
						|
*        Case 4: R = M-Q
 | 
						|
*
 | 
						|
*        Simultaneously bidiagonalize X11 and X21
 | 
						|
*
 | 
						|
         CALL SORBDB4( M, P, Q, X11, LDX11, X21, LDX21, THETA,
 | 
						|
     $                 WORK(IPHI), WORK(ITAUP1), WORK(ITAUP2),
 | 
						|
     $                 WORK(ITAUQ1), WORK(IORBDB), WORK(IORBDB+M),
 | 
						|
     $                 LORBDB-M, CHILDINFO )
 | 
						|
*
 | 
						|
*        Accumulate Householder reflectors
 | 
						|
*
 | 
						|
         IF( WANTU1 .AND. P .GT. 0 ) THEN
 | 
						|
            CALL SCOPY( P, WORK(IORBDB), 1, U1, 1 )
 | 
						|
            DO J = 2, P
 | 
						|
               U1(1,J) = ZERO
 | 
						|
            END DO
 | 
						|
            CALL SLACPY( 'L', P-1, M-Q-1, X11(2,1), LDX11, U1(2,2),
 | 
						|
     $                   LDU1 )
 | 
						|
            CALL SORGQR( P, P, M-Q, U1, LDU1, WORK(ITAUP1),
 | 
						|
     $                   WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTU2 .AND. M-P .GT. 0 ) THEN
 | 
						|
            CALL SCOPY( M-P, WORK(IORBDB+P), 1, U2, 1 )
 | 
						|
            DO J = 2, M-P
 | 
						|
               U2(1,J) = ZERO
 | 
						|
            END DO
 | 
						|
            CALL SLACPY( 'L', M-P-1, M-Q-1, X21(2,1), LDX21, U2(2,2),
 | 
						|
     $                   LDU2 )
 | 
						|
            CALL SORGQR( M-P, M-P, M-Q, U2, LDU2, WORK(ITAUP2),
 | 
						|
     $                   WORK(IORGQR), LORGQR, CHILDINFO )
 | 
						|
         END IF
 | 
						|
         IF( WANTV1T .AND. Q .GT. 0 ) THEN
 | 
						|
            CALL SLACPY( 'U', M-Q, Q, X21, LDX21, V1T, LDV1T )
 | 
						|
            CALL SLACPY( 'U', P-(M-Q), Q-(M-Q), X11(M-Q+1,M-Q+1), LDX11,
 | 
						|
     $                   V1T(M-Q+1,M-Q+1), LDV1T )
 | 
						|
            CALL SLACPY( 'U', -P+Q, Q-P, X21(M-Q+1,P+1), LDX21,
 | 
						|
     $                   V1T(P+1,P+1), LDV1T )
 | 
						|
            CALL SORGLQ( Q, Q, Q, V1T, LDV1T, WORK(ITAUQ1),
 | 
						|
     $                   WORK(IORGLQ), LORGLQ, CHILDINFO )
 | 
						|
         END IF
 | 
						|
*   
 | 
						|
*        Simultaneously diagonalize X11 and X21.
 | 
						|
*   
 | 
						|
         CALL SBBCSD( JOBU2, JOBU1, 'N', JOBV1T, 'N', M, M-P, M-Q,
 | 
						|
     $                THETA, WORK(IPHI), U2, LDU2, U1, LDU1, 0, 1, V1T,
 | 
						|
     $                LDV1T, WORK(IB11D), WORK(IB11E), WORK(IB12D),
 | 
						|
     $                WORK(IB12E), WORK(IB21D), WORK(IB21E),
 | 
						|
     $                WORK(IB22D), WORK(IB22E), WORK(IBBCSD), LBBCSD,
 | 
						|
     $                CHILDINFO )
 | 
						|
*   
 | 
						|
*        Permute rows and columns to place identity submatrices in
 | 
						|
*        preferred positions
 | 
						|
*
 | 
						|
         IF( P .GT. R ) THEN
 | 
						|
            DO I = 1, R
 | 
						|
               IWORK(I) = P - R + I
 | 
						|
            END DO
 | 
						|
            DO I = R + 1, P
 | 
						|
               IWORK(I) = I - R
 | 
						|
            END DO
 | 
						|
            IF( WANTU1 ) THEN
 | 
						|
               CALL SLAPMT( .FALSE., P, P, U1, LDU1, IWORK )
 | 
						|
            END IF
 | 
						|
            IF( WANTV1T ) THEN
 | 
						|
               CALL SLAPMR( .FALSE., P, Q, V1T, LDV1T, IWORK )
 | 
						|
            END IF
 | 
						|
         END IF
 | 
						|
      END IF
 | 
						|
*
 | 
						|
      RETURN
 | 
						|
*
 | 
						|
*     End of SORCSD2BY1
 | 
						|
*
 | 
						|
      END
 | 
						|
 |