Time integrate_n_steps(
Stepper stepper , System system , State &start_state ,
Time start_time , Time dt , size_t num_of_steps ,
Observer observer , dense_output_stepper_tag )
{
typename odeint::unwrap_reference< Observer >::type &obs = observer;
Time time = start_time;
const Time end_time = start_time + static_cast< typename unit_value_type<Time>::type >(num_of_steps) * dt;
stepper.initialize( start_state , time , dt );
size_t step = 0;
while( step < num_of_steps )
{
while( less_with_sign( time , stepper.current_time() , stepper.current_time_step() ) )
{
stepper.calc_state( time , start_state );
obs( start_state , time );
++step;
// direct computation of the time avoids error propagation happening when using time += dt
// we need clumsy type analysis to get boost units working here
time = start_time + static_cast< typename unit_value_type<Time>::type >(step) * dt;
}
// we have not reached the end, do another real step
if( less_with_sign( stepper.current_time()+stepper.current_time_step() ,
end_time ,
stepper.current_time_step() ) )
{
stepper.do_step( system );
}
else if( less_with_sign( stepper.current_time() , end_time , stepper.current_time_step() ) )
{ // do the last step ending exactly on the end point
stepper.initialize( stepper.current_state() , stepper.current_time() , end_time - stepper.current_time() );
stepper.do_step( system );
}
}
while( stepper.current_time() < end_time )
{
if( less_with_sign( end_time ,
stepper.current_time()+stepper.current_time_step() ,
stepper.current_time_step() ) )
stepper.initialize( stepper.current_state() , stepper.current_time() , end_time - stepper.current_time() );
stepper.do_step( system );
}
// observation at end point, only if we ended exactly on the end-point (or above due to finite precision)
obs( stepper.current_state() , end_time );
return time;
}
void check_dense_output_stepper( Stepper &stepper )
{
typedef Stepper stepper_type;
typedef typename stepper_type::state_type state_type;
typedef typename stepper_type::value_type value_type;
typedef typename stepper_type::deriv_type deriv_type;
typedef typename stepper_type::time_type time_type;
// typedef typename stepper_type::order_type order_type;
time_type t( 0.0 * si::second );
time_type dt( 0.1 * si::second );
state_type x( 1.0 * si::meter , 0.0 * si::meter_per_second ) , x2;
stepper.initialize( x , t , dt );
stepper.do_step( oscillator );
stepper.calc_state( dt / 2.0 , x2 );
}
