!-------------------------------------- LICENCE BEGIN ------------------------------------
!Environment Canada - Atmospheric Science and Technology License/Disclaimer,
!                     version 3; Last Modified: May 7, 2008.
!This is free but copyrighted software; you can use/redistribute/modify it under the terms
!of the Environment Canada - Atmospheric Science and Technology License/Disclaimer
!version 3 or (at your option) any later version that should be found at:
!http://collaboration.cmc.ec.gc.ca/science/rpn.comm/license.html
!
!This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
!without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
!See the above mentioned License/Disclaimer for more details.
!You should have received a copy of the License/Disclaimer along with this software;
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!CANADA, H9P 1J3; or send e-mail to service.rpn@ec.gc.ca
!-------------------------------------- LICENCE END --------------------------------------
!
!
!  X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X
!

      subroutine lap(psol,pf,cdgrid) 4,6
!
!**s/r lap  - Applies the Laplacian operator to field pf.
!
!
!Author  : Luc Fillion - MSC - 10 March 04.
!Revision:
!
!     -------------------
!
!Arguments
!
      implicit none
!
#include "taglam4d.cdk"
#include "comct0.cdk"
#include "pardim.cdk"
#include "comdim.cdk"
#include "comcst.cdk"
#include "comlun.cdk"
#include "comfftla.cdk"
!
      character*1 cdgrid
      real*8 psol(ni,nj)
      real*8 pf(ni,nj)
!
      real*8 zcyc(nj),zreal(nj),zimag(nj)
      real*8 zsol(nj)
      real*8 zspsol(nfi,2,nj)
      real*8 zpm(nfi)
!
      integer ji,jj,jk,jfi
      real*8 zdlon,zdlat,zdlon2,zdlat2,zalpha,zbeta,za,zra2,zcon
      real*8 zdenom,zdenom2
!
!!
      call zero(2*nfi*nj,zspsol)
      call zero(ni*nj,psol)
!
!       Fourier Transform rhs in the zonal direction
!
        do jj=1,nj
          call dft1d(zspsol(1,1,jj),pf(1,jj),sdft1d,mlen1d,ni)
        enddo
!
!       Applies meridional part of Laplacian for each zonal wavenumbers
!
        do jfi=1,nfi
          do jj=1,nj
             zreal(jj)=zspsol(jfi,1,jj)
             zimag(jj)=zspsol(jfi,2,jj)
          enddo
          call lapm(zsol,zreal,cdgrid,jfi)
          do jj=1,nj
             zspsol(jfi,1,jj)=zsol(jj)
          enddo
          call lapm(zsol,zimag,cdgrid,jfi)
          do jj=1,nj
             zspsol(jfi,2,jj)=zsol(jj)
          enddo
        enddo
!
!       Inverse Fourier Transform solution in the zonal direction
!
        do jj=1,nj
          call idft1d(psol(1,jj),zspsol(1,1,jj),sdft1d,mlen1d,ni)
        enddo
!
      return
      end