size_t integrate_adaptive(
Stepper stepper , System system , State &start_state ,
Time &start_time , Time end_time , Time &dt ,
Observer observer , controlled_stepper_tag
)
{
typename omplext_odeint::unwrap_reference< Observer >::type &obs = observer;
const size_t max_attempts = 1000;
const char *error_string = "Integrate adaptive : Maximal number of iterations reached. A step size could not be found.";
size_t count = 0;
while( less_with_sign( start_time , end_time , dt ) )
{
obs( start_state , start_time );
if( less_with_sign( end_time , start_time + dt , dt ) )
{
dt = end_time - start_time;
}
size_t trials = 0;
controlled_step_result res = success;
do
{
res = stepper.try_step( system , start_state , start_time , dt );
++trials;
}
while( ( res == fail ) && ( trials < max_attempts ) );
if( trials == max_attempts ) throw std::overflow_error( error_string );
++count;
}
obs( start_state , start_time );
return count;
}
void check_controlled_stepper_concept( Stepper &stepper , System system , typename Stepper::state_type &x )
{
typedef Stepper stepper_type;
typedef typename stepper_type::deriv_type container_type;
//typedef typename stepper_type::order_type order_type; controlled_error_stepper don't necessarily have a order (burlish-stoer)
typedef typename stepper_type::time_type time_type;
time_type t = 0.0 , dt = 0.1;
controlled_step_result step_result = stepper.try_step( system , x , t , dt );
BOOST_CHECK_MESSAGE( step_result == success , "step result: " << step_result ); // error = 0 for constant system -> step size is always too small
}
void check_controlled_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;
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 );
// test call method one
stepper.try_step( oscillator , x , t , dt );
}
void operator()( void )
{
mpf_set_default_prec( precision );
mpf_t eps_ , unity;
mpf_init( eps_ ); mpf_init( unity );
mpf_set_d( unity , 1.0 );
mpf_div_2exp( eps_ , unity , precision-1 ); // 2^(-precision+1) : smallest number that can be represented with used precision
value_type eps( eps_ );
Stepper stepper;
state_type x;
x = 0.0;
value_type t(0.0);
value_type dt(0.1);
stepper.try_step( constant_system , x , t , dt );
BOOST_MESSAGE( eps );
BOOST_CHECK_MESSAGE( abs( x - value_type( 0.1 , precision ) ) < eps , x - 0.1 );
}
