[BACK]Return to zlaed0.f CVS log [TXT] [DIR] Up to [local] / rpl / lapack / lapack

Diff for /rpl/lapack/lapack/zlaed0.f between versions 1.7 and 1.18

version 1.7, 2010/12/21 13:53:49 version 1.18, 2023/08/07 08:39:28
Line 1 Line 1
   *> \brief \b ZLAED0 used by ZSTEDC. Computes all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method.
   *
   *  =========== DOCUMENTATION ===========
   *
   * Online html documentation available at
   *            http://www.netlib.org/lapack/explore-html/
   *
   *> \htmlonly
   *> Download ZLAED0 + dependencies
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlaed0.f">
   *> [TGZ]</a>
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlaed0.f">
   *> [ZIP]</a>
   *> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlaed0.f">
   *> [TXT]</a>
   *> \endhtmlonly
   *
   *  Definition:
   *  ===========
   *
   *       SUBROUTINE ZLAED0( QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK,
   *                          IWORK, INFO )
   *
   *       .. Scalar Arguments ..
   *       INTEGER            INFO, LDQ, LDQS, N, QSIZ
   *       ..
   *       .. Array Arguments ..
   *       INTEGER            IWORK( * )
   *       DOUBLE PRECISION   D( * ), E( * ), RWORK( * )
   *       COMPLEX*16         Q( LDQ, * ), QSTORE( LDQS, * )
   *       ..
   *
   *
   *> \par Purpose:
   *  =============
   *>
   *> \verbatim
   *>
   *> Using the divide and conquer method, ZLAED0 computes all eigenvalues
   *> of a symmetric tridiagonal matrix which is one diagonal block of
   *> those from reducing a dense or band Hermitian matrix and
   *> corresponding eigenvectors of the dense or band matrix.
   *> \endverbatim
   *
   *  Arguments:
   *  ==========
   *
   *> \param[in] QSIZ
   *> \verbatim
   *>          QSIZ is INTEGER
   *>         The dimension of the unitary matrix used to reduce
   *>         the full matrix to tridiagonal form.  QSIZ >= N if ICOMPQ = 1.
   *> \endverbatim
   *>
   *> \param[in] N
   *> \verbatim
   *>          N is INTEGER
   *>         The dimension of the symmetric tridiagonal matrix.  N >= 0.
   *> \endverbatim
   *>
   *> \param[in,out] D
   *> \verbatim
   *>          D is DOUBLE PRECISION array, dimension (N)
   *>         On entry, the diagonal elements of the tridiagonal matrix.
   *>         On exit, the eigenvalues in ascending order.
   *> \endverbatim
   *>
   *> \param[in,out] E
   *> \verbatim
   *>          E is DOUBLE PRECISION array, dimension (N-1)
   *>         On entry, the off-diagonal elements of the tridiagonal matrix.
   *>         On exit, E has been destroyed.
   *> \endverbatim
   *>
   *> \param[in,out] Q
   *> \verbatim
   *>          Q is COMPLEX*16 array, dimension (LDQ,N)
   *>         On entry, Q must contain an QSIZ x N matrix whose columns
   *>         unitarily orthonormal. It is a part of the unitary matrix
   *>         that reduces the full dense Hermitian matrix to a
   *>         (reducible) symmetric tridiagonal matrix.
   *> \endverbatim
   *>
   *> \param[in] LDQ
   *> \verbatim
   *>          LDQ is INTEGER
   *>         The leading dimension of the array Q.  LDQ >= max(1,N).
   *> \endverbatim
   *>
   *> \param[out] IWORK
   *> \verbatim
   *>          IWORK is INTEGER array,
   *>         the dimension of IWORK must be at least
   *>                      6 + 6*N + 5*N*lg N
   *>                      ( lg( N ) = smallest integer k
   *>                                  such that 2^k >= N )
   *> \endverbatim
   *>
   *> \param[out] RWORK
   *> \verbatim
   *>          RWORK is DOUBLE PRECISION array,
   *>                               dimension (1 + 3*N + 2*N*lg N + 3*N**2)
   *>                        ( lg( N ) = smallest integer k
   *>                                    such that 2^k >= N )
   *> \endverbatim
   *>
   *> \param[out] QSTORE
   *> \verbatim
   *>          QSTORE is COMPLEX*16 array, dimension (LDQS, N)
   *>         Used to store parts of
   *>         the eigenvector matrix when the updating matrix multiplies
   *>         take place.
   *> \endverbatim
   *>
   *> \param[in] LDQS
   *> \verbatim
   *>          LDQS is INTEGER
   *>         The leading dimension of the array QSTORE.
   *>         LDQS >= max(1,N).
   *> \endverbatim
   *>
   *> \param[out] INFO
   *> \verbatim
   *>          INFO is INTEGER
   *>          = 0:  successful exit.
   *>          < 0:  if INFO = -i, the i-th argument had an illegal value.
   *>          > 0:  The algorithm failed to compute an eigenvalue while
   *>                working on the submatrix lying in rows and columns
   *>                INFO/(N+1) through mod(INFO,N+1).
   *> \endverbatim
   *
   *  Authors:
   *  ========
   *
   *> \author Univ. of Tennessee
   *> \author Univ. of California Berkeley
   *> \author Univ. of Colorado Denver
   *> \author NAG Ltd.
   *
   *> \ingroup complex16OTHERcomputational
   *
   *  =====================================================================
       SUBROUTINE ZLAED0( QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK,        SUBROUTINE ZLAED0( QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, RWORK,
      $                   IWORK, INFO )       $                   IWORK, INFO )
 *  *
 *  -- LAPACK routine (version 3.2) --  *  -- LAPACK computational routine --
 *  -- 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..--
 *     November 2006  
 *  *
 *     .. Scalar Arguments ..  *     .. Scalar Arguments ..
       INTEGER            INFO, LDQ, LDQS, N, QSIZ        INTEGER            INFO, LDQ, LDQS, N, QSIZ
Line 15 Line 156
       COMPLEX*16         Q( LDQ, * ), QSTORE( LDQS, * )        COMPLEX*16         Q( LDQ, * ), QSTORE( LDQS, * )
 *     ..  *     ..
 *  *
 *  Purpose  
 *  =======  
 *  
 *  Using the divide and conquer method, ZLAED0 computes all eigenvalues  
 *  of a symmetric tridiagonal matrix which is one diagonal block of  
 *  those from reducing a dense or band Hermitian matrix and  
 *  corresponding eigenvectors of the dense or band matrix.  
 *  
 *  Arguments  
 *  =========  
 *  
 *  QSIZ   (input) INTEGER  
 *         The dimension of the unitary matrix used to reduce  
 *         the full matrix to tridiagonal form.  QSIZ >= N if ICOMPQ = 1.  
 *  
 *  N      (input) INTEGER  
 *         The dimension of the symmetric tridiagonal matrix.  N >= 0.  
 *  
 *  D      (input/output) DOUBLE PRECISION array, dimension (N)  
 *         On entry, the diagonal elements of the tridiagonal matrix.  
 *         On exit, the eigenvalues in ascending order.  
 *  
 *  E      (input/output) DOUBLE PRECISION array, dimension (N-1)  
 *         On entry, the off-diagonal elements of the tridiagonal matrix.  
 *         On exit, E has been destroyed.  
 *  
 *  Q      (input/output) COMPLEX*16 array, dimension (LDQ,N)  
 *         On entry, Q must contain an QSIZ x N matrix whose columns  
 *         unitarily orthonormal. It is a part of the unitary matrix  
 *         that reduces the full dense Hermitian matrix to a  
 *         (reducible) symmetric tridiagonal matrix.  
 *  
 *  LDQ    (input) INTEGER  
 *         The leading dimension of the array Q.  LDQ >= max(1,N).  
 *  
 *  IWORK  (workspace) INTEGER array,  
 *         the dimension of IWORK must be at least  
 *                      6 + 6*N + 5*N*lg N  
 *                      ( lg( N ) = smallest integer k  
 *                                  such that 2^k >= N )  
 *  
 *  RWORK  (workspace) DOUBLE PRECISION array,  
 *                               dimension (1 + 3*N + 2*N*lg N + 3*N**2)  
 *                        ( lg( N ) = smallest integer k  
 *                                    such that 2^k >= N )  
 *  
 *  QSTORE (workspace) COMPLEX*16 array, dimension (LDQS, N)  
 *         Used to store parts of  
 *         the eigenvector matrix when the updating matrix multiplies  
 *         take place.  
 *  
 *  LDQS   (input) INTEGER  
 *         The leading dimension of the array QSTORE.  
 *         LDQS >= max(1,N).  
 *  
 *  INFO   (output) INTEGER  
 *          = 0:  successful exit.  
 *          < 0:  if INFO = -i, the i-th argument had an illegal value.  
 *          > 0:  The algorithm failed to compute an eigenvalue while  
 *                working on the submatrix lying in rows and columns  
 *                INFO/(N+1) through mod(INFO,N+1).  
 *  
 *  =====================================================================  *  =====================================================================
 *  *
 *  Warning:      N could be as big as QSIZ!  *  Warning:      N could be as big as QSIZ!
Removed from v.1.7  
changed lines
  Added in v.1.18

CVSweb interface <joel.bertrand@systella.fr>