typename Stepper::time_type integrate_const_steps(
	Stepper &stepper ,
	DynamicalSystem &system ,
	typename Stepper::container_type &state ,
	typename Stepper::time_type start_time ,
	typename Stepper::time_type dt ,
	size_t num_of_steps ,
	Observer &observer
	)
    {
        stepper.adjust_size( state );
	size_t iteration = 0;
        while( iteration < num_of_steps )
	{
	    observer( start_time , state , system );
            stepper.do_step( system , state , start_time , dt );
            start_time += dt;
	    ++iteration;
        }
	observer( start_time , state , system );

	return start_time;
    }