C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/eesupp/src/exch_xy_rx.template,v 1.3 2001/09/21 03:55:50 cnh Exp $
C $Name:  $

#include "CPP_EEOPTIONS.h"

CBOP

C     !ROUTINE: EXCH_XY_RX

C     !INTERFACE:
      SUBROUTINE EXCH_XY_RX( 
     U                       phi, 
     I                       myThid )
      IMPLICIT NONE
C     !DESCRIPTION:
C     *==========================================================*
C     | SUBROUTINE EXCH_XY_RX                                     
C     | o Handle exchanges for _RX two-dimensional scalar arrays.
C     *==========================================================*
C     | Invoke appropriate exchange for a scalar array for either
C     | global grid, or cube sphere grid.                         
C     *==========================================================*

C     !USES:
C     === Global data ===
#include "SIZE.h"
#include "EEPARAMS.h"
#include "EESUPPORT.h"

C     !INPUT/OUTPUT PARAMETERS:
C     === Routine arguments ===
C     phi    :: Array with overlap regions are to be exchanged
C     myThid :: My thread id.
      _RX phi(1-OLx:sNx+OLx,1-OLy:sNy+OLy,nSx,nSy)
      INTEGER myThid

C     !LOCAL VARIABLES:
C     == Local variables ==
C     OL[wens]       :: Overlap extents in west, east, north, south.
C     exchWidth[XY]  :: Extent of regions that will be exchanged.
      INTEGER OLw, OLe, OLn, OLs, exchWidthX, exchWidthY, myNz
CEOP

      OLw        = OLx
      OLe        = OLx
      OLn        = OLy
      OLs        = OLy
      exchWidthX = OLx
      exchWidthY = OLy
      myNz       = 1
C     ** NOTE ** The exchange routine we use here does not 
C                require the preceeding and following barriers.
C                However, the slow, simple exchange interface 
C                that is calling it here is meant to ensure 
C                that threads are synchronised before exchanges
C                begine.
      IF (useCubedSphereExchange) THEN
       CALL EXCH_RX_CUBE( phi,
     I            OLw, OLe, OLs, OLn, myNz,
     I            exchWidthX, exchWidthY,
     I            FORWARD_SIMULATION, EXCH_UPDATE_CORNERS, myThid )
      ELSE
       CALL EXCH_RX( phi,
     I            OLw, OLe, OLs, OLn, myNz,
     I            exchWidthX, exchWidthY,
     I            FORWARD_SIMULATION, EXCH_UPDATE_CORNERS, myThid )
      ENDIF

      RETURN
      END