PZLASWP(l)					      LAPACK auxiliary routine (version 1.5)						PZLASWP(l)

NAME

       PZLASWP - perform a series of row or column interchanges on the distributed matrix sub( A ) = A(IA:IA+M-1,JA:JA+N-1)

SYNOPSIS

       SUBROUTINE PZLASWP( DIREC, ROWCOL, N, A, IA, JA, DESCA, K1, K2, IPIV )

	   CHARACTER	   DIREC, ROWCOL

	   INTEGER	   IA, JA, K1, K2, N

	   INTEGER	   DESCA( * ), IPIV( * )

	   COMPLEX*16	   A( * )

PURPOSE

       PZLASWP	performs  a  series of row or column interchanges on the distributed matrix sub( A ) = A(IA:IA+M-1,JA:JA+N-1).	One interchange is
       initiated for each of rows or columns K1 trough K2 of sub( A ). This routine assumes that the pivoting information has already been  broad-
       cast along the process row or column.
       Also note that this routine will only work for K1-K2 being in the same MB (or NB) block.  If you want to pivot a full matrix, use PZLAPIV.

       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

       DIREC   (global input) CHARACTER
	       Specifies in which order the permutation is applied: = 'F' (Forward) = 'B' (Backward)

       ROWCOL  (global input) CHARACTER
	       Specifies if the rows or columns are permuted: = 'R' (Rows) = 'C' (Columns)

       N       (global input) INTEGER
	       If ROWCOL = 'R', the length of the rows of the distributed matrix A(*,JA:JA+N-1) to be permuted; If ROWCOL = 'C', the length of the
	       columns of the distributed matrix A(IA:IA+N-1,*) to be permuted.

       A       (local input/local output) COMPLEX*16 pointer into the
	       local memory to an array of dimension (LLD_A, * ).  On entry, this array contains the local pieces of the distri- buted	matrix	to
	       which the row/columns interchanges will be applied. On exit the permuted distributed matrix.

       IA      (global input) INTEGER
	       The row index in the global array A indicating the first row of sub( A ).

       JA      (global input) INTEGER
	       The column index in the global array A indicating the first column of sub( A ).

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

       K1      (global input) INTEGER
	       The first element of IPIV for which a row or column inter- change will be done.

       K2      (global input) INTEGER
	       The last element of IPIV for which a row or column inter- change will be done.

       IPIV    (local input) INTEGER array, dimension LOCr(M_A)+MB_A for
	       row  pivoting  and LOCc(N_A)+NB_A for column pivoting.  This array is tied to the matrix A, IPIV(K) = L implies rows (or columns) K
	       and L are to be interchanged.

LAPACK version 1.5						    12 May 1997 							PZLASWP(l)