!-------------------------------------- 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
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!This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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!See the above mentioned License/Disclaimer for more details.
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!
!
!  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 lapm(pout,pin,cdgrid,kfi) 2,2
!
!**s/r lapm  - Computes the Laplacian for a given zonal component
!
!
!Author  : Luc Fillion - MSC - 10 March 04.
!Revision:
!
!     -------------------
!
!Arguments
!
      implicit none
!
#include "taglam4d.cdk"
#include "pardim.cdk"
#include "comdim.cdk"
#include "comgrd_param.cdk"
#include "comct0.cdk"
#include "comcst.cdk"
#include "comlun.cdk"
#include "comgemla.cdk"
!
      integer kfi
      real*8 pin(nj),pout(nj)
!
      real*8 za(nj),zb(nj),zax(nj),zc(nj),zr(nj)
      real*8 zalpha,zbeta,zcon
!
      character*1 cdgrid
      logical lsettri
      integer jj
!
!!
      call zero(nj,pout)
!
!     Build cyclic tridiagonal matrix A
!
      call settrilax(za,zb,zc,zalpha,zbeta,cdgrid,kfi)
! 
!     compute A*x
!
      do jj=2,nj-1
        pout(jj)=za(jj)*pin(jj-1)+zb(jj)*pin(jj)+zc(jj)*pin(jj+1)
      enddo
!
      pout(1)=zb(1)*pin(1)+zc(1)*pin(2) + zbeta*pin(nj)
      pout(nj)=zalpha*pin(1) +  za(nj)*pin(nj-1)+zb(nj)*pin(nj) 
!
      return
      end