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version 1.8, 2010/12/21 13:53:29 version 1.9, 2011/11/21 20:42:55
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   *> \brief \b DLAEXC
   *
   *  =========== DOCUMENTATION ===========
   *
   * Online html documentation available at 
   *            http://www.netlib.org/lapack/explore-html/ 
   *
   *> \htmlonly
   *> Download DLAEXC + dependencies 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/dlaexc.f"> 
   *> [TGZ]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/dlaexc.f"> 
   *> [ZIP]</a> 
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/dlaexc.f"> 
   *> [TXT]</a>
   *> \endhtmlonly 
   *
   *  Definition:
   *  ===========
   *
   *       SUBROUTINE DLAEXC( WANTQ, N, T, LDT, Q, LDQ, J1, N1, N2, WORK,
   *                          INFO )
   * 
   *       .. Scalar Arguments ..
   *       LOGICAL            WANTQ
   *       INTEGER            INFO, J1, LDQ, LDT, N, N1, N2
   *       ..
   *       .. Array Arguments ..
   *       DOUBLE PRECISION   Q( LDQ, * ), T( LDT, * ), WORK( * )
   *       ..
   *  
   *
   *> \par Purpose:
   *  =============
   *>
   *> \verbatim
   *>
   *> DLAEXC swaps adjacent diagonal blocks T11 and T22 of order 1 or 2 in
   *> an upper quasi-triangular matrix T by an orthogonal similarity
   *> transformation.
   *>
   *> T must be in Schur canonical form, that is, block upper triangular
   *> with 1-by-1 and 2-by-2 diagonal blocks; each 2-by-2 diagonal block
   *> has its diagonal elemnts equal and its off-diagonal elements of
   *> opposite sign.
   *> \endverbatim
   *
   *  Arguments:
   *  ==========
   *
   *> \param[in] WANTQ
   *> \verbatim
   *>          WANTQ is LOGICAL
   *>          = .TRUE. : accumulate the transformation in the matrix Q;
   *>          = .FALSE.: do not accumulate the transformation.
   *> \endverbatim
   *>
   *> \param[in] N
   *> \verbatim
   *>          N is INTEGER
   *>          The order of the matrix T. N >= 0.
   *> \endverbatim
   *>
   *> \param[in,out] T
   *> \verbatim
   *>          T is DOUBLE PRECISION array, dimension (LDT,N)
   *>          On entry, the upper quasi-triangular matrix T, in Schur
   *>          canonical form.
   *>          On exit, the updated matrix T, again in Schur canonical form.
   *> \endverbatim
   *>
   *> \param[in] LDT
   *> \verbatim
   *>          LDT is INTEGER
   *>          The leading dimension of the array T. LDT >= max(1,N).
   *> \endverbatim
   *>
   *> \param[in,out] Q
   *> \verbatim
   *>          Q is DOUBLE PRECISION array, dimension (LDQ,N)
   *>          On entry, if WANTQ is .TRUE., the orthogonal matrix Q.
   *>          On exit, if WANTQ is .TRUE., the updated matrix Q.
   *>          If WANTQ is .FALSE., Q is not referenced.
   *> \endverbatim
   *>
   *> \param[in] LDQ
   *> \verbatim
   *>          LDQ is INTEGER
   *>          The leading dimension of the array Q.
   *>          LDQ >= 1; and if WANTQ is .TRUE., LDQ >= N.
   *> \endverbatim
   *>
   *> \param[in] J1
   *> \verbatim
   *>          J1 is INTEGER
   *>          The index of the first row of the first block T11.
   *> \endverbatim
   *>
   *> \param[in] N1
   *> \verbatim
   *>          N1 is INTEGER
   *>          The order of the first block T11. N1 = 0, 1 or 2.
   *> \endverbatim
   *>
   *> \param[in] N2
   *> \verbatim
   *>          N2 is INTEGER
   *>          The order of the second block T22. N2 = 0, 1 or 2.
   *> \endverbatim
   *>
   *> \param[out] WORK
   *> \verbatim
   *>          WORK is DOUBLE PRECISION array, dimension (N)
   *> \endverbatim
   *>
   *> \param[out] INFO
   *> \verbatim
   *>          INFO is INTEGER
   *>          = 0: successful exit
   *>          = 1: the transformed matrix T would be too far from Schur
   *>               form; the blocks are not swapped and T and Q are
   *>               unchanged.
   *> \endverbatim
   *
   *  Authors:
   *  ========
   *
   *> \author Univ. of Tennessee 
   *> \author Univ. of California Berkeley 
   *> \author Univ. of Colorado Denver 
   *> \author NAG Ltd. 
   *
   *> \date November 2011
   *
   *> \ingroup doubleOTHERauxiliary
   *
   *  =====================================================================
       SUBROUTINE DLAEXC( WANTQ, N, T, LDT, Q, LDQ, J1, N1, N2, WORK,        SUBROUTINE DLAEXC( WANTQ, N, T, LDT, Q, LDQ, J1, N1, N2, WORK,
      $                   INFO )       $                   INFO )
 *  *
 *  -- LAPACK auxiliary routine (version 3.2.2) --  *  -- LAPACK auxiliary routine (version 3.4.0) --
 *  -- LAPACK is a software package provided by Univ. of Tennessee,    --  *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
 *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--  *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
 *     June 2010  *     November 2011
 *  *
 *     .. Scalar Arguments ..  *     .. Scalar Arguments ..
       LOGICAL            WANTQ        LOGICAL            WANTQ
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       DOUBLE PRECISION   Q( LDQ, * ), T( LDT, * ), WORK( * )        DOUBLE PRECISION   Q( LDQ, * ), T( LDT, * ), WORK( * )
 *     ..  *     ..
 *  *
 *  Purpose  
 *  =======  
 *  
 *  DLAEXC swaps adjacent diagonal blocks T11 and T22 of order 1 or 2 in  
 *  an upper quasi-triangular matrix T by an orthogonal similarity  
 *  transformation.  
 *  
 *  T must be in Schur canonical form, that is, block upper triangular  
 *  with 1-by-1 and 2-by-2 diagonal blocks; each 2-by-2 diagonal block  
 *  has its diagonal elemnts equal and its off-diagonal elements of  
 *  opposite sign.  
 *  
 *  Arguments  
 *  =========  
 *  
 *  WANTQ   (input) LOGICAL  
 *          = .TRUE. : accumulate the transformation in the matrix Q;  
 *          = .FALSE.: do not accumulate the transformation.  
 *  
 *  N       (input) INTEGER  
 *          The order of the matrix T. N >= 0.  
 *  
 *  T       (input/output) DOUBLE PRECISION array, dimension (LDT,N)  
 *          On entry, the upper quasi-triangular matrix T, in Schur  
 *          canonical form.  
 *          On exit, the updated matrix T, again in Schur canonical form.  
 *  
 *  LDT     (input) INTEGER  
 *          The leading dimension of the array T. LDT >= max(1,N).  
 *  
 *  Q       (input/output) DOUBLE PRECISION array, dimension (LDQ,N)  
 *          On entry, if WANTQ is .TRUE., the orthogonal matrix Q.  
 *          On exit, if WANTQ is .TRUE., the updated matrix Q.  
 *          If WANTQ is .FALSE., Q is not referenced.  
 *  
 *  LDQ     (input) INTEGER  
 *          The leading dimension of the array Q.  
 *          LDQ >= 1; and if WANTQ is .TRUE., LDQ >= N.  
 *  
 *  J1      (input) INTEGER  
 *          The index of the first row of the first block T11.  
 *  
 *  N1      (input) INTEGER  
 *          The order of the first block T11. N1 = 0, 1 or 2.  
 *  
 *  N2      (input) INTEGER  
 *          The order of the second block T22. N2 = 0, 1 or 2.  
 *  
 *  WORK    (workspace) DOUBLE PRECISION array, dimension (N)  
 *  
 *  INFO    (output) INTEGER  
 *          = 0: successful exit  
 *          = 1: the transformed matrix T would be too far from Schur  
 *               form; the blocks are not swapped and T and Q are  
 *               unchanged.  
 *  
 *  =====================================================================  *  =====================================================================
 *  *
 *     .. Parameters ..  *     .. Parameters ..
Removed from v.1.8  
changed lines
  Added in v.1.9

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