Well, I'll be damned. It is actually coded so that freq=-20 produces snapshot at timestep 10. Why is that? D. -- Dimitris Menemenlis <menemenlis at jpl.nasa.gov> Jet Propulsion Lab, California Institute of Technology MS 300-323, 4800 Oak Grove Dr, Pasadena CA 91109-8099 tel: 818-354-1656; fax: 818-393-6720