#include "dims.h"
      SUBROUTINE SWDOT
      use cons_module,only: imax,imaxp2,kmax,kmaxp1,kut,len1,len3,
     |  expzmid
      implicit none
C     ****     CALCULATES W ON LINE NJ AND Z TO NJNP
#include "params.h"
#include "fcom.h"
#include "vscr.h"
#include "index.h"
#include "buff.h"
#include "phys.h"
!
! Local:
      integer :: i,k,nwk,nznpk,nzk,kk
!
C     ****     S1=DIVRG(V)
      CALL DIVRG(S1)
C     ****      INSERT PERIODIC POINTS  FOR W
      DO I=1,2
        DO K=1,KMAX
          S1(I,K)=S1(I+IMAX,K)
          S1(I+IMAXP2,K)=S1(I+2,K)
        enddo
      enddo

!     call addfsech('SWDOT_S1',' ',' ',s1,zimxp,zkmxp,zkmx,j)

C     ****     W(KMAXP1)=S1(KMAX)
      NWK=NJNP+NW
      DO 1 I=1,LEN1
        F(I,NWK+KMAX)=S1(I,KMAX)
    1 CONTINUE
C     ****     W(K)=expzmid*(expzmid*W(K+1)+dz*S1(K))
      NWK=NWK+KMAX
      DO KK=1,KMAX
        K=KMAXP1-KK
        NWK=NWK-1
        DO I=1,LEN1
          F(I,NWK)=expzmid*(expzmid*F(I,NWK+1)+dz*S1(I,K))
        enddo
      enddo
      NZNPK=NJNP+NZ
      NZK=NJ+NZ
      DO 3 I=1,LEN3
        F(I,NZNPK)=F(I,NZK)
    3 CONTINUE
      NWK=NJNP+NW
      CALL FILTER(NWK,KMAXP1,KUT(J))

!     call addfsech('SWDOT_W',' ',' ',f(1,njnp+nw),zimxp,zkmxp,zkmxp,j)
!     call addfsech('SWDOT_Z',' ',' ',f(1,njnp+nz),zimxp,zkmxp,zkmxp,j)

      END