c
      subroutine actmov
c
c  this routine performs the active motion on
c  entity n.
c
      include 'active.inc'
      include 'domain.inc'
c
c  insert local variable definitions here.
c  *** ALL VARIABLES MUST BE DECLARED ***
c
      double precision sign, xdef, ydef, period, factor
      integer i
c
c  insert dynamic changes here
c

      period = 0.05d0
      factor = 0.5d0
      xdef = 1.0d0

      sign = factor*dsin(6.283185307d0*time/period)/xdef

      if (elab.eq.1) then
         ydef = 4.0d0
         do i=1,40
            tethy(i) = ydef - sign*(xdef-tethx(i))*(xdef+tethx(i))
         enddo
      else
          ydef = 4.1d0
         do i=1,40
            tethy(i) = ydef - sign*(xdef-tethx(i))*(xdef+tethx(i))
         enddo
      endif

c
      return
      end     
c
c--------------------------------------------------------------
c
      subroutine getsrc (ntsrc)
c
c  user routine that specifies the sources
c
      implicit none
c
      include 'domain.inc'
      include 'sink.inc'
c
c  global variables
c
      integer ntsrc
c
c  insert local variable definitions here.
c  *** ALL VARIABLES MUST BE DECLARED ***
c
c  specify the location (xsourc,ysourc) and strength
c  of a source (src) here.
c
c  The user should be sure the number of sources and
c  sinks does not exceed the number declared in the
c  .ibis file
c
      ntsrc = 0
c
      return
      end