1 /* 2 [auto_generated] 3 boost/numeric/odeint/stepper/explicit_error_generic_rk.hpp 4 5 [begin_description] 6 Implementation of the generic Runge Kutta error stepper. Base class for many RK error steppers. 7 [end_description] 8 9 Copyright 2011-2013 Mario Mulansky 10 Copyright 2011-2013 Karsten Ahnert 11 Copyright 2012 Christoph Koke 12 13 Distributed under the Boost Software License, Version 1.0. 14 (See accompanying file LICENSE_1_0.txt or 15 copy at http://www.boost.org/LICENSE_1_0.txt) 16 */ 17 18 19 #ifndef BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED 20 #define BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED 21 22 #include <boost/numeric/odeint/stepper/base/explicit_error_stepper_base.hpp> 23 24 #include <boost/numeric/odeint/algebra/default_operations.hpp> 25 #include <boost/numeric/odeint/algebra/range_algebra.hpp> 26 #include <boost/numeric/odeint/algebra/algebra_dispatcher.hpp> 27 #include <boost/numeric/odeint/algebra/operations_dispatcher.hpp> 28 #include <boost/numeric/odeint/stepper/detail/generic_rk_algorithm.hpp> 29 #include <boost/numeric/odeint/stepper/detail/generic_rk_call_algebra.hpp> 30 #include <boost/numeric/odeint/stepper/detail/generic_rk_operations.hpp> 31 32 #include <boost/numeric/odeint/util/state_wrapper.hpp> 33 #include <boost/numeric/odeint/util/is_resizeable.hpp> 34 #include <boost/numeric/odeint/util/resizer.hpp> 35 36 37 38 namespace boost { 39 namespace numeric { 40 namespace odeint { 41 42 43 template< 44 size_t StageCount, 45 size_t Order, 46 size_t StepperOrder , 47 size_t ErrorOrder , 48 class State , 49 class Value = double , 50 class Deriv = State , 51 class Time = Value , 52 class Algebra = typename algebra_dispatcher< State >::algebra_type , 53 class Operations = typename operations_dispatcher< State >::operations_type , 54 class Resizer = initially_resizer 55 > 56 #ifndef DOXYGEN_SKIP 57 class explicit_error_generic_rk 58 : public explicit_error_stepper_base< 59 explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , 60 Value , Deriv , Time , Algebra , Operations , Resizer > , 61 Order , StepperOrder , ErrorOrder , State , Value , Deriv , Time , Algebra , 62 Operations , Resizer > 63 #else 64 class explicit_error_generic_rk : public explicit_error_stepper_base 65 #endif 66 { 67 68 public: 69 #ifndef DOXYGEN_SKIP 70 typedef explicit_error_stepper_base< 71 explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , 72 Value , Deriv , Time , Algebra , Operations , Resizer > , 73 Order , StepperOrder , ErrorOrder , State , Value , Deriv , Time , Algebra , 74 Operations , Resizer > stepper_base_type; 75 #else 76 typedef explicit_stepper_base< ... > stepper_base_type; 77 #endif 78 typedef typename stepper_base_type::state_type state_type; 79 typedef typename stepper_base_type::wrapped_state_type wrapped_state_type; 80 typedef typename stepper_base_type::value_type value_type; 81 typedef typename stepper_base_type::deriv_type deriv_type; 82 typedef typename stepper_base_type::wrapped_deriv_type wrapped_deriv_type; 83 typedef typename stepper_base_type::time_type time_type; 84 typedef typename stepper_base_type::algebra_type algebra_type; 85 typedef typename stepper_base_type::operations_type operations_type; 86 typedef typename stepper_base_type::resizer_type resizer_type; 87 #ifndef DOXYGEN_SKIP 88 typedef explicit_error_generic_rk< StageCount , Order , StepperOrder , ErrorOrder , State , 89 Value , Deriv , Time , Algebra , Operations , Resizer > stepper_type; 90 #endif 91 typedef detail::generic_rk_algorithm< StageCount , Value , Algebra , Operations > rk_algorithm_type; 92 93 typedef typename rk_algorithm_type::coef_a_type coef_a_type; 94 typedef typename rk_algorithm_type::coef_b_type coef_b_type; 95 typedef typename rk_algorithm_type::coef_c_type coef_c_type; 96 97 static const size_t stage_count = StageCount; 98 99 private: 100 101 102 public: 103 104 // we use an explicit_generic_rk to do the normal rk step 105 // and add a separate calculation of the error estimate afterwards explicit_error_generic_rk(const coef_a_type & a,const coef_b_type & b,const coef_b_type & b2,const coef_c_type & c,const algebra_type & algebra=algebra_type ())106 explicit_error_generic_rk( const coef_a_type &a , 107 const coef_b_type &b , 108 const coef_b_type &b2 , 109 const coef_c_type &c , 110 const algebra_type &algebra = algebra_type() ) 111 : stepper_base_type( algebra ) , m_rk_algorithm( a , b , c ) , m_b2( b2 ) 112 { } 113 114 115 template< class System , class StateIn , class DerivIn , class StateOut , class Err > do_step_impl(System system,const StateIn & in,const DerivIn & dxdt,time_type t,StateOut & out,time_type dt,Err & xerr)116 void do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , 117 time_type t , StateOut &out , time_type dt , Err &xerr ) 118 { 119 // normal step 120 do_step_impl( system , in , dxdt , t , out , dt ); 121 122 // additionally, perform the error calculation 123 detail::template generic_rk_call_algebra< StageCount , algebra_type >()( stepper_base_type::m_algebra , 124 xerr , dxdt , m_F , detail::generic_rk_scale_sum_err< StageCount , operations_type , value_type , time_type >( m_b2 , dt) ); 125 } 126 127 128 template< class System , class StateIn , class DerivIn , class StateOut > do_step_impl(System system,const StateIn & in,const DerivIn & dxdt,time_type t,StateOut & out,time_type dt)129 void do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , 130 time_type t , StateOut &out , time_type dt ) 131 { 132 m_resizer.adjust_size( in , detail::bind( &stepper_type::template resize_impl< StateIn > , detail::ref( *this ) , detail::_1 ) ); 133 134 // actual calculation done in generic_rk.hpp 135 m_rk_algorithm.do_step( stepper_base_type::m_algebra , system , in , dxdt , t , out , dt , m_x_tmp.m_v , m_F ); 136 } 137 138 139 template< class StateIn > adjust_size(const StateIn & x)140 void adjust_size( const StateIn &x ) 141 { 142 resize_impl( x ); 143 stepper_base_type::adjust_size( x ); 144 } 145 146 147 private: 148 149 template< class StateIn > resize_impl(const StateIn & x)150 bool resize_impl( const StateIn &x ) 151 { 152 bool resized( false ); 153 resized |= adjust_size_by_resizeability( m_x_tmp , x , typename is_resizeable<state_type>::type() ); 154 for( size_t i = 0 ; i < StageCount-1 ; ++i ) 155 { 156 resized |= adjust_size_by_resizeability( m_F[i] , x , typename is_resizeable<deriv_type>::type() ); 157 } 158 return resized; 159 } 160 161 162 rk_algorithm_type m_rk_algorithm; 163 coef_b_type m_b2; 164 165 resizer_type m_resizer; 166 167 wrapped_state_type m_x_tmp; 168 wrapped_deriv_type m_F[StageCount-1]; 169 170 }; 171 172 173 /********* DOXYGEN *********/ 174 175 /** 176 * \class explicit_error_generic_rk 177 * \brief A generic implementation of explicit Runge-Kutta algorithms with error estimation. This class is as a 178 * base class for all explicit Runge-Kutta steppers with error estimation. 179 * 180 * This class implements the explicit Runge-Kutta algorithms with error estimation in a generic way. 181 * The Butcher tableau is passed to the stepper which constructs the stepper scheme with the help of a 182 * template-metaprogramming algorithm. ToDo : Add example! 183 * 184 * This class derives explicit_error_stepper_base which provides the stepper interface. 185 * 186 * \tparam StageCount The number of stages of the Runge-Kutta algorithm. 187 * \tparam Order The order of a stepper if the stepper is used without error estimation. 188 * \tparam StepperOrder The order of a step if the stepper is used with error estimation. Usually Order and StepperOrder have 189 * the same value. 190 * \tparam ErrorOrder The order of the error step if the stepper is used with error estimation. 191 * \tparam State The type representing the state of the ODE. 192 * \tparam Value The floating point type which is used in the computations. 193 * \tparam Time The type representing the independent variable - the time - of the ODE. 194 * \tparam Algebra The algebra type. 195 * \tparam Operations The operations type. 196 * \tparam Resizer The resizer policy type. 197 */ 198 199 200 /** 201 * \fn explicit_error_generic_rk::explicit_error_generic_rk( const coef_a_type &a , const coef_b_type &b , const coef_b_type &b2 , const coef_c_type &c , const algebra_type &algebra ) 202 * \brief Constructs the explicit_error_generik_rk class with the given parameters a, b, b2 and c. See examples section for details on the coefficients. 203 * 204 * \param a Triangular matrix of parameters b in the Butcher tableau. 205 * \param b Last row of the butcher tableau. 206 * \param b2 Parameters for lower-order evaluation to estimate the error. 207 * \param c Parameters to calculate the time points in the Butcher tableau. 208 * \param algebra A copy of algebra is made and stored inside explicit_stepper_base. 209 */ 210 211 212 /** 213 * \fn explicit_error_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt , Err &xerr ) 214 * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method. 215 * The result is updated out-of-place, hence the input is in `in` and the output in `out`. Futhermore, an 216 * estimation of the error is stored in `xerr`. `do_step_impl` is used by explicit_error_stepper_base. 217 * 218 * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the 219 * Simple System concept. 220 * \param in The state of the ODE which should be solved. in is not modified in this method 221 * \param dxdt The derivative of x at t. 222 * \param t The value of the time, at which the step should be performed. 223 * \param out The result of the step is written in out. 224 * \param dt The step size. 225 * \param xerr The result of the error estimation is written in xerr. 226 */ 227 228 /** 229 * \fn explicit_error_generic_rk::do_step_impl( System system , const StateIn &in , const DerivIn &dxdt , time_type t , StateOut &out , time_type dt ) 230 * \brief This method performs one step. The derivative `dxdt` of `in` at the time `t` is passed to the method. 231 * The result is updated out-of-place, hence the input is in `in` and the output in `out`. 232 * Access to this step functionality is provided by explicit_stepper_base and 233 * `do_step_impl` should not be called directly. 234 * 235 * \param system The system function to solve, hence the r.h.s. of the ODE. It must fulfill the 236 * Simple System concept. 237 * \param in The state of the ODE which should be solved. in is not modified in this method 238 * \param dxdt The derivative of x at t. 239 * \param t The value of the time, at which the step should be performed. 240 * \param out The result of the step is written in out. 241 * \param dt The step size. 242 */ 243 244 /** 245 * \fn explicit_error_generic_rk::adjust_size( const StateIn &x ) 246 * \brief Adjust the size of all temporaries in the stepper manually. 247 * \param x A state from which the size of the temporaries to be resized is deduced. 248 */ 249 250 } 251 } 252 } 253 254 255 #endif // BOOST_NUMERIC_ODEINT_STEPPER_EXPLICIT_ERROR_GENERIC_RK_HPP_INCLUDED 256