        for pi in particles:
            self.channel_to_framework.append(self.code.particles.new_channel_to(pi))
            self.channel_from_framework.append(pi.new_channel_to(self.code.particles))

    @property
    def model_time(self):
        return self.code.model_time
    @property
    def stop(self):
        return self.code.stop