def sim
      @stopped = catch :stop_simulation do
        begin
          fired = fire_transitions
          advanced = move_clock_to find_next_time
        end while fired || advanced
      end
      @stopped = false if @stopped == nil
    rescue StandardError => e
      raise SimulationError.new(e)
    end
def sim
      @stopped = catch :stop_simulation do
        begin
          fired = fire_transitions
          advanced = move_clock_to find_next_time
        end while fired || advanced
      end
      @stopped = false if @stopped == nil
    rescue StandardError => e
      raise SimulationError.new(e)
    end
Starts simulation of this net.