void do_step_impl( System system , const StateIn &in , const time_type &t , StateOut &out , const time_type &dt , boost::mpl::true_ )
{
typedef typename detail::unwrap_reference< System >::type system_type;
typedef typename detail::unwrap_reference< typename system_type::first_type >::type coor_deriv_func_type;
typedef typename detail::unwrap_reference< typename system_type::second_type >::type momentum_deriv_func_type;
system_type &sys = system;
coor_deriv_func_type &coor_func = sys.first;
momentum_deriv_func_type &momentum_func = sys.second;
typedef typename detail::unwrap_reference< StateIn >::type state_in_type;
typedef typename detail::unwrap_reference< typename state_in_type::first_type >::type coor_in_type;
typedef typename detail::unwrap_reference< typename state_in_type::second_type >::type momentum_in_type;
const state_in_type &state_in = in;
const coor_in_type &coor_in = state_in.first;
const momentum_in_type &momentum_in = state_in.second;
typedef typename detail::unwrap_reference< StateOut >::type state_out_type;
typedef typename detail::unwrap_reference< typename state_out_type::first_type >::type coor_out_type;
typedef typename detail::unwrap_reference< typename state_out_type::second_type >::type momentum_out_type;
state_out_type &state_out = out;
coor_out_type &coor_out = state_out.first;
momentum_out_type &momentum_out = state_out.second;
m_dqdt_resizer.adjust_size( coor_in , detail::bind( &internal_stepper_base_type::template resize_dqdt< coor_in_type > , detail::ref( *this ) , detail::_1 ) );
m_dpdt_resizer.adjust_size( momentum_in , detail::bind( &internal_stepper_base_type::template resize_dpdt< momentum_in_type > , detail::ref( *this ) , detail::_1 ) );
// ToDo: check sizes?
for( size_t l=0 ; l<num_of_stages ; ++l )
{
if( l == 0 )
{
coor_func( momentum_in , m_dqdt.m_v );
this->m_algebra.for_each3( coor_out , coor_in , m_dqdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_a[l] * dt ) );
momentum_func( coor_out , m_dpdt.m_v );
this->m_algebra.for_each3( momentum_out , momentum_in , m_dpdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_b[l] * dt ) );
}
else
{
coor_func( momentum_out , m_dqdt.m_v );
this->m_algebra.for_each3( coor_out , coor_out , m_dqdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_a[l] * dt ) );
momentum_func( coor_out , m_dpdt.m_v );
this->m_algebra.for_each3( momentum_out , momentum_out , m_dpdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_b[l] * dt ) );
}
}
}
void do_step_impl( System system , const StateIn &in , time_type /* t */ , StateOut &out , time_type dt , boost::mpl::false_ )
{
typedef typename odeint::unwrap_reference< System >::type momentum_deriv_func_type;
momentum_deriv_func_type &momentum_func = system;
typedef typename odeint::unwrap_reference< StateIn >::type state_in_type;
typedef typename odeint::unwrap_reference< typename state_in_type::first_type >::type coor_in_type;
typedef typename odeint::unwrap_reference< typename state_in_type::second_type >::type momentum_in_type;
const state_in_type &state_in = in;
const coor_in_type &coor_in = state_in.first;
const momentum_in_type &momentum_in = state_in.second;
typedef typename odeint::unwrap_reference< StateOut >::type state_out_type;
typedef typename odeint::unwrap_reference< typename state_out_type::first_type >::type coor_out_type;
typedef typename odeint::unwrap_reference< typename state_out_type::second_type >::type momentum_out_type;
state_out_type &state_out = out;
coor_out_type &coor_out = state_out.first;
momentum_out_type &momentum_out = state_out.second;
// m_dqdt not required when called with momentum_func only - don't resize
// m_dqdt_resizer.adjust_size( coor_in , detail::bind( &internal_stepper_base_type::template resize_dqdt< coor_in_type > , detail::ref( *this ) , detail::_1 ) );
m_dpdt_resizer.adjust_size( momentum_in , detail::bind( &internal_stepper_base_type::template resize_dpdt< momentum_in_type > , detail::ref( *this ) , detail::_1 ) );
// ToDo: check sizes?
// step 0
this->m_algebra.for_each3( coor_out , coor_in , momentum_in ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_a[0] * dt ) );
momentum_func( coor_out , m_dpdt.m_v );
this->m_algebra.for_each3( momentum_out , momentum_in , m_dpdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_b[0] * dt ) );
for( size_t l=1 ; l<num_of_stages ; ++l )
{
this->m_algebra.for_each3( coor_out , coor_out , momentum_out ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_a[l] * dt ) );
momentum_func( coor_out , m_dpdt.m_v );
this->m_algebra.for_each3( momentum_out , momentum_out , m_dpdt.m_v ,
typename operations_type::template scale_sum2< value_type , time_type >( 1.0 , m_coef_b[l] * dt ) );
}
}
