NAME

       PCLAEVSWP  -  move  the  eigenvectors (potentially unsorted) from where they are computed, to a ScaLAPACK
       standard block cyclic array, sorted so that the corresponding eigenvalues are sorted

SYNOPSIS

       SUBROUTINE PCLAEVSWP( N, ZIN, LDZI, Z, IZ, JZ, DESCZ, NVS, KEY, RWORK, LRWORK )

           INTEGER           IZ, JZ, LDZI, LRWORK, N

           INTEGER           DESCZ( * ), KEY( * ), NVS( * )

           REAL              RWORK( * ), ZIN( LDZI, * )

           COMPLEX           Z( * )

PURPOSE

       PCLAEVSWP moves the eigenvectors (potentially unsorted) from where they  are  computed,  to  a  ScaLAPACK
       standard block cyclic array, sorted so that the corresponding eigenvalues are sorted.

       Notes
       =====

       Each  global  data  object  is  described  by  an  associated description vector.  This vector stores the
       information required to establish the mapping between an object element and its corresponding process and
       memory location.

       Let A be a generic term for any 2D block  cyclicly  distributed  array.   Such  a  global  array  has  an
       associated  description  vector  DESCA.  In the following comments, the character _ should be read as "of
       the global array".

       NOTATION        STORED IN      EXPLANATION
       --------------- -------------- -------------------------------------- DTYPE_A(global) DESCA( DTYPE_  )The
       descriptor type.  In this case,
                                      DTYPE_A = 1.
       CTXT_A (global) DESCA( CTXT_ ) The BLACS context handle, indicating
                                      the BLACS process grid A is distribu-
                                      ted over. The context itself is glo-
                                      bal, but the handle (the integer
                                      value) may vary.
       M_A    (global) DESCA( M_ )    The number of rows in the global
                                      array A.
       N_A    (global) DESCA( N_ )    The number of columns in the global
                                      array A.
       MB_A   (global) DESCA( MB_ )   The blocking factor used to distribute
                                      the rows of the array.
       NB_A   (global) DESCA( NB_ )   The blocking factor used to distribute
                                      the columns of the array.
       RSRC_A (global) DESCA( RSRC_ ) The process row over which the first
                                      row  of  the  array  A is distributed.  CSRC_A (global) DESCA( CSRC_ ) The
       process column over which the
                                      first column of the array A is
                                      distributed.
       LLD_A  (local)  DESCA( LLD_ )  The leading dimension of the local
                                      array.  LLD_A >= MAX(1,LOCr(M_A)).

       Let K be the number of rows or columns of a distributed matrix, and assume  that  its  process  grid  has
       dimension p x q.
       LOCr( K ) denotes the number of elements of K that a process would receive if K were distributed over the
       p processes of its process column.
       Similarly,  LOCc(  K  )  denotes  the  number  of  elements  of  K that a process would receive if K were
       distributed over the q processes of its process row.
       The values of LOCr() and LOCc() may be determined via a call to the ScaLAPACK tool function, NUMROC:
               LOCr( M ) = NUMROC( M, MB_A, MYROW, RSRC_A, NPROW ),
               LOCc( N ) = NUMROC( N, NB_A, MYCOL, CSRC_A, NPCOL ).  An upper bound for these quantities may  be
       computed by:
               LOCr( M ) <= ceil( ceil(M/MB_A)/NPROW )*MB_A
               LOCc( N ) <= ceil( ceil(N/NB_A)/NPCOL )*NB_A

ARGUMENTS

       NP = the number of rows local to a given process.  NQ = the number of columns local to a given process.

       N       (global input) INTEGER
               The order of the matrix A.  N >= 0.

       ZIN     (local input) REAL array,
               dimension ( LDZI, NVS(iam) ) The eigenvectors on input.  Each eigenvector resides entirely in one
               process.   Each  process  holds a contiguous set of NVS(iam) eigenvectors.  The first eigenvector
               which the process holds is:  sum for i=[0,iam-1) of NVS(i)

       LDZI    (locl input) INTEGER
               leading dimension of the ZIN array

       Z       (local output) COMPLEX array
               global dimension (N, N), local dimension (DESCZ(DLEN_), NQ)  The  eigenvectors  on  output.   The
               eigenvectors  are  distributed  in a block cyclic manner in both dimensions, with a block size of
               NB.

       IZ      (global input) INTEGER
               Z's global row index, which points to the beginning of the submatrix which is to be operated on.

       JZ      (global input) INTEGER
               Z's global column index, which points to the beginning of the submatrix which is to  be  operated
               on.

       DESCZ   (global and local input) INTEGER array of dimension DLEN_.
               The array descriptor for the distributed matrix Z.

       NVS     (global input) INTEGER array, dimension( nprocs+1 )
               nvs(i)  = number of processes number of eigenvectors held by processes [0,i-1) nvs(1) = number of
               eigen vectors held by [0,1-1) == 0 nvs(nprocs+1) = number of eigen vectors held by [0,nprocs)  ==
               total number of eigenvectors

       KEY     (global input) INTEGER array, dimension( N )
               Indicates the actual index (after sorting) for each of the eigenvectors.

       RWORK    (local workspace) REAL array, dimension (LRWORK)

       LRWORK   (local input) INTEGER dimension of RWORK

LAPACK version 1.5                                 12 May 1997                                      PCLAEVSWP(l)