************************************************************************
*     Randall R. Correll
*     Mijan F. Huq
*     Scott A. Klasky
*     Richard A. Matzner
*
*     COPYRIGHT 1995-1996

*  Computes the timestep for the next iteration of the update scheme.
************************************************************************
      subroutine timestep(dx,dy,dz,dt)

      implicit none

      real*8   dx,dy,dz,dt
      real*8   dmin

      dmin = dx
      if ( dy .lt. dmin ) then 
         dmin = dy
      end if
      if ( dz .lt. dmin ) then
         dmin = dz
      end if

      dt = dmin/4.0d0

      return
      end