364 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			Fortran
		
	
	
	
			
		
		
	
	
			364 lines
		
	
	
		
			8.8 KiB
		
	
	
	
		
			Fortran
		
	
	
	
| *> \brief \b CSYCONV
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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 CSYCONV + dependencies
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| *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/csyconv.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/csyconv.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/csyconv.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 CSYCONV( UPLO, WAY, N, A, LDA, IPIV, E, INFO )
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| *
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| *       .. Scalar Arguments ..
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| *       CHARACTER          UPLO, WAY
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| *       INTEGER            INFO, LDA, N
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| *       ..
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| *       .. Array Arguments ..
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| *       INTEGER            IPIV( * )
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| *       COMPLEX            A( LDA, * ), E( * )
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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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| *> CSYCONV convert A given by TRF into L and D and vice-versa.
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| *> Get Non-diag elements of D (returned in workspace) and
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| *> apply or reverse permutation done in TRF.
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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] UPLO
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| *> \verbatim
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| *>          UPLO is CHARACTER*1
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| *>          Specifies whether the details of the factorization are stored
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| *>          as an upper or lower triangular matrix.
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| *>          = 'U':  Upper triangular, form is A = U*D*U**T;
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| *>          = 'L':  Lower triangular, form is A = L*D*L**T.
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| *> \endverbatim
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| *>
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| *> \param[in] WAY
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| *> \verbatim
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| *>          WAY is CHARACTER*1
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| *>          = 'C': Convert
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| *>          = 'R': Revert
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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 order of the matrix A.  N >= 0.
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| *> \endverbatim
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| *>
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| *> \param[in,out] A
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| *> \verbatim
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| *>          A is COMPLEX array, dimension (LDA,N)
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| *>          The block diagonal matrix D and the multipliers used to
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| *>          obtain the factor U or L as computed by CSYTRF.
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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 array A.  LDA >= max(1,N).
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| *> \endverbatim
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| *>
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| *> \param[in] IPIV
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| *> \verbatim
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| *>          IPIV is INTEGER array, dimension (N)
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| *>          Details of the interchanges and the block structure of D
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| *>          as determined by CSYTRF.
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| *> \endverbatim
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| *>
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| *> \param[out] E
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| *> \verbatim
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| *>          E is COMPLEX array, dimension (N)
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| *>          E stores the supdiagonal/subdiagonal of the symmetric 1-by-1
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| *>          or 2-by-2 block diagonal matrix D in LDLT.
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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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| *> \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 complexSYcomputational
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| *
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| *  =====================================================================
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|       SUBROUTINE CSYCONV( UPLO, WAY, N, A, LDA, IPIV, E, INFO )
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| *
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| *  -- LAPACK computational 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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|       CHARACTER          UPLO, WAY
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|       INTEGER            INFO, LDA, N
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| *     ..
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| *     .. Array Arguments ..
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|       INTEGER            IPIV( * )
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|       COMPLEX            A( LDA, * ), E( * )
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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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|       COMPLEX            ZERO
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|       PARAMETER          ( ZERO = (0.0E+0,0.0E+0) )
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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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| *     .. External Subroutines ..
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|       EXTERNAL           XERBLA
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| *     .. Local Scalars ..
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|       LOGICAL            UPPER, CONVERT
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|       INTEGER            I, IP, J
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|       COMPLEX            TEMP
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| *     ..
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| *     .. Executable Statements ..
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| *
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|       INFO = 0
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|       UPPER = LSAME( UPLO, 'U' )
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|       CONVERT = LSAME( WAY, 'C' )
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|       IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
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|          INFO = -1
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|       ELSE IF( .NOT.CONVERT .AND. .NOT.LSAME( WAY, 'R' ) ) THEN
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|          INFO = -2
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|       ELSE IF( N.LT.0 ) THEN
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|          INFO = -3
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|       ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
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|          INFO = -5
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| 
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|       END IF
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|       IF( INFO.NE.0 ) THEN
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|          CALL XERBLA( 'CSYCONV', -INFO )
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|          RETURN
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|       END IF
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| *
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| *     Quick return if possible
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| *
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|       IF( N.EQ.0 )
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|      $   RETURN
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| *
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|       IF( UPPER ) THEN
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| *
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| *      A is UPPER
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| *
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| *      Convert A (A is upper)
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| *
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| *        Convert VALUE
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| *
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|          IF ( CONVERT ) THEN
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|             I=N
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|             E(1)=ZERO
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|             DO WHILE ( I .GT. 1 )
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|                IF( IPIV(I) .LT. 0 ) THEN
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|                   E(I)=A(I-1,I)
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|                   E(I-1)=ZERO
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|                   A(I-1,I)=ZERO
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|                   I=I-1
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|                ELSE
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|                   E(I)=ZERO
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|                ENDIF
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|                I=I-1
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|             END DO
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| *
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| *        Convert PERMUTATIONS
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| *
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|          I=N
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|          DO WHILE ( I .GE. 1 )
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|             IF( IPIV(I) .GT. 0) THEN
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|                IP=IPIV(I)
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|                IF( I .LT. N) THEN
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|                   DO 12 J= I+1,N
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|                     TEMP=A(IP,J)
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|                     A(IP,J)=A(I,J)
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|                     A(I,J)=TEMP
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|  12            CONTINUE
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|                ENDIF
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|             ELSE
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|               IP=-IPIV(I)
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|                IF( I .LT. N) THEN
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|              DO 13 J= I+1,N
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|                  TEMP=A(IP,J)
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|                  A(IP,J)=A(I-1,J)
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|                  A(I-1,J)=TEMP
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|  13            CONTINUE
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|                 ENDIF
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|                 I=I-1
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|            ENDIF
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|            I=I-1
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|         END DO
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| 
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|          ELSE
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| *
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| *      Revert A (A is upper)
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| *
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| *
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| *        Revert PERMUTATIONS
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| *
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|             I=1
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|             DO WHILE ( I .LE. N )
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|                IF( IPIV(I) .GT. 0 ) THEN
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|                   IP=IPIV(I)
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|                   IF( I .LT. N) THEN
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|                   DO J= I+1,N
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|                     TEMP=A(IP,J)
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|                     A(IP,J)=A(I,J)
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|                     A(I,J)=TEMP
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|                   END DO
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|                   ENDIF
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|                ELSE
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|                  IP=-IPIV(I)
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|                  I=I+1
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|                  IF( I .LT. N) THEN
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|                     DO J= I+1,N
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|                        TEMP=A(IP,J)
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|                        A(IP,J)=A(I-1,J)
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|                        A(I-1,J)=TEMP
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|                     END DO
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|                  ENDIF
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|                ENDIF
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|                I=I+1
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|             END DO
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| *
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| *        Revert VALUE
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| *
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|             I=N
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|             DO WHILE ( I .GT. 1 )
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|                IF( IPIV(I) .LT. 0 ) THEN
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|                   A(I-1,I)=E(I)
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|                   I=I-1
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|                ENDIF
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|                I=I-1
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|             END DO
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|          END IF
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|       ELSE
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| *
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| *      A is LOWER
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| *
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|          IF ( CONVERT ) THEN
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| *
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| *      Convert A (A is lower)
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| *
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| *
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| *        Convert VALUE
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| *
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|             I=1
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|             E(N)=ZERO
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|             DO WHILE ( I .LE. N )
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|                IF( I.LT.N .AND. IPIV(I) .LT. 0 ) THEN
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|                   E(I)=A(I+1,I)
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|                   E(I+1)=ZERO
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|                   A(I+1,I)=ZERO
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|                   I=I+1
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|                ELSE
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|                   E(I)=ZERO
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|                ENDIF
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|                I=I+1
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|             END DO
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| *
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| *        Convert PERMUTATIONS
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| *
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|          I=1
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|          DO WHILE ( I .LE. N )
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|             IF( IPIV(I) .GT. 0 ) THEN
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|                IP=IPIV(I)
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|                IF (I .GT. 1) THEN
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|                DO 22 J= 1,I-1
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|                  TEMP=A(IP,J)
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|                  A(IP,J)=A(I,J)
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|                  A(I,J)=TEMP
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|  22            CONTINUE
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|                ENDIF
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|             ELSE
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|               IP=-IPIV(I)
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|               IF (I .GT. 1) THEN
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|               DO 23 J= 1,I-1
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|                  TEMP=A(IP,J)
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|                  A(IP,J)=A(I+1,J)
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|                  A(I+1,J)=TEMP
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|  23           CONTINUE
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|               ENDIF
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|               I=I+1
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|            ENDIF
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|            I=I+1
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|         END DO
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|          ELSE
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| *
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| *      Revert A (A is lower)
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| *
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| *
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| *        Revert PERMUTATIONS
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| *
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|             I=N
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|             DO WHILE ( I .GE. 1 )
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|                IF( IPIV(I) .GT. 0 ) THEN
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|                   IP=IPIV(I)
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|                   IF (I .GT. 1) THEN
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|                      DO J= 1,I-1
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|                         TEMP=A(I,J)
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|                         A(I,J)=A(IP,J)
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|                         A(IP,J)=TEMP
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|                      END DO
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|                   ENDIF
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|                ELSE
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|                   IP=-IPIV(I)
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|                   I=I-1
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|                   IF (I .GT. 1) THEN
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|                      DO J= 1,I-1
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|                         TEMP=A(I+1,J)
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|                         A(I+1,J)=A(IP,J)
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|                         A(IP,J)=TEMP
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|                      END DO
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|                   ENDIF
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|                ENDIF
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|                I=I-1
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|             END DO
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| *
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| *        Revert VALUE
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| *
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|             I=1
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|             DO WHILE ( I .LE. N-1 )
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|                IF( IPIV(I) .LT. 0 ) THEN
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|                   A(I+1,I)=E(I)
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|                   I=I+1
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|                ENDIF
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|                I=I+1
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|             END DO
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|          END IF
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|       END IF
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| 
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|       RETURN
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| *
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| *     End of CSYCONV
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| *
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|       END
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