C $Header: /home/ubuntu/mnt/e9_copy/MITgcm/model/src/update_r_star.F,v 1.1 2003/01/26 21:06:11 jmc Exp $
C $Name:  $

#include "CPP_OPTIONS.h"

CBOP
C     !ROUTINE: UPDATE_R_STAR
C     !INTERFACE:
      SUBROUTINE UPDATE_R_STAR( myTime, myIter, myThid )
C     !DESCRIPTION: \bv
C     *==========================================================*
C     | SUBROUTINE UPDATE_R_STAR                                 
C     | o Update the thickness fractions (hFacC,W,S) 
C     |   according to the surface r-position = Non-Linear FrSurf 
C     *==========================================================*
C     \ev

C     !USES:
      IMPLICIT NONE
C     == Global variables
#include "SIZE.h"
#include "EEPARAMS.h"
#include "PARAMS.h"
c #include "DYNVARS.h"
#include "GRID.h"
#include "SURFACE.h"

C     !INPUT/OUTPUT PARAMETERS:
C     == Routine arguments ==
C     myTime - Current time in simulation
C     myIter - Current iteration number in simulation
C     myThid - Thread number for this instance of the routine.
      _RL myTime
      INTEGER myIter
      INTEGER myThid

C     !LOCAL VARIABLES:
#ifdef NONLIN_FRSURF
C     Local variables
C     i,j,k,bi,bj - loop counter
      INTEGER i,j,k,bi,bj
CEOP

      DO bj=myByLo(myThid), myByHi(myThid)
       DO bi=myBxLo(myThid), myBxHi(myThid)  

C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|

c #ifdef ALLOW_OBCS
c C-- Apply OBC to hFac_surfW,S before updating hFacW,S
c         IF (useOBCS) CALL OBCS_APPLY_SURF_DR(
c      I                    bi, bj, ksurfC, ksurfW, ksurfS,
c      U                    hFac_surfC, hFac_surfW, hFac_surfS,
c      I                    myThid )
c #endif /* ALLOW_OBCS */

        DO k=1,Nr
         DO j=1-Oly,sNy+Oly
          DO i=1-Olx,sNx+Olx 
C-- Update the fractional thickness hFacC , hFacW & hFacS (& "recip_hFac") :
            hFacC(i,j,k,bi,bj) = h0FacC(i,j,k,bi,bj)
     &                          *rStarFacC(i,j,bi,bj)
            hFacW(i,j,k,bi,bj) = h0FacW(i,j,k,bi,bj)
     &                          *rStarFacW(i,j,bi,bj)
            hFacS(i,j,k,bi,bj) = h0FacS(i,j,k,bi,bj)
     &                          *rStarFacS(i,j,bi,bj)
#ifdef USE_MASK_AND_NO_IF
            recip_hFacC(i,j,k,bi,bj) = maskC(i,j,k,bi,bj)
     &        / ( hFacC(i,j,k,bi,bj) + (1.-maskC(i,j,k,bi,bj)) )
            recip_hFacW(i,j,k,bi,bj) = maskW(i,j,k,bi,bj)
     &        / ( hFacW(i,j,k,bi,bj) + (1.-maskW(i,j,k,bi,bj)) )
            recip_hFacS(i,j,k,bi,bj) = maskS(i,j,k,bi,bj)
     &        / ( hFacS(i,j,k,bi,bj) + (1.-maskS(i,j,k,bi,bj)) )
#else
           IF (maskC(i,j,k,bi,bj).NE.0.)
     &      recip_hFacC(i,j,k,bi,bj) = 1. _d 0 / hFacC(i,j,k,bi,bj)
           IF (maskW(i,j,k,bi,bj).NE.0.)
     &      recip_hFacW(i,j,k,bi,bj) = 1. _d 0 / hFacW(i,j,k,bi,bj)
           IF (maskS(i,j,k,bi,bj).NE.0.)
     &      recip_hFacS(i,j,k,bi,bj) = 1. _d 0 / hFacS(i,j,k,bi,bj)
#endif
          ENDDO
         ENDDO
        ENDDO

C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|

C- end bi,bj loop
       ENDDO
      ENDDO

c     _EXCH_XYZ_RS( hFacC, myThid )
c     _EXCH_XYZ_RS( recip_hFacC, myThid )
c     CALL EXCH_UV_XYZ_RS(hFacW,hFacS,.FALSE.,myThid)
c     CALL EXCH_UV_XYZ_RS(recip_hFacW,recip_hFacS,.FALSE.,myThid)

C---+----1----+----2----+----3----+----4----+----5----+----6----+----7-|--+----|
#endif /* NONLIN_FRSURF */

      RETURN
      END