PSLAEVSWP(l)						   LAPACK routine (version 1.5) 					      PSLAEVSWP(l)

NAME

       PSLAEVSWP  -  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 PSLAEVSWP( N, ZIN, LDZI, Z, IZ, JZ, DESCZ, NVS, KEY, WORK, LWORK )

	   INTEGER	     IZ, JZ, LDZI, LWORK, N

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

	   REAL 	     WORK( * ), Z( * ), ZIN( LDZI, * )

PURPOSE

       PSLAEVSWP 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 col-
       umn.
       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) REAL 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.

       WORK    (local workspace) REAL array, dimension (LWORK)

       LWORK   (local input) INTEGER dimension of WORK

LAPACK version 1.5						    12 May 1997 						      PSLAEVSWP(l)