subroutine real_comp(ac,as,a,imode)
c
c Translates between our old (c,s) and complex notation.
c imode = 1  -> from (c,s) to complex 
c imode = -1 -> from complex to (c,s)
c

      implicit none
      include 'itg.par'
      include 'itg.cmn'

      real ac(lz,mz,nz),as(lz,mz,nz)
      complex a(lz,mz,nz)
      integer l,m,n,imode

      if(imode.eq.1) then
         do l=1,ld
            do m=1,md
               do n=1,nd
                  a(l,m,n)=cmplx(ac(l,m,n),-as(l,m,n))
               enddo
            enddo
         enddo
      else if(imode.eq.-1) then
         do l=1,ld
            do m=1,md
               do n=1,nd
                  ac(l,m,n)=real(a(l,m,n))
                  as(l,m,n)=-aimag(a(l,m,n))
               enddo
            enddo
         enddo
      endif

      return
      end