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initial odeint commit
[SVN r81491]
This commit is contained in:
Karsten Ahnert
294
examples/const_step_iterator.cpp
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294
examples/const_step_iterator.cpp
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/*
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* const_step_iterator.cpp
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*
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* Copyright 2009-2012 Karsten Ahnert
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* Copyright 2009-2012 Mario Mulansky
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*
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* Distributed under the Boost Software License, Version 1.0.
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* (See accompanying file LICENSE_1_0.txt or
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* copy at http://www.boost.org/LICENSE_1_0.txt)
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*/
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#include <iostream>
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#include <iterator>
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#include <utility>
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#include <algorithm>
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#include <array>
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#include <cassert>
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#include <boost/range/algorithm.hpp>
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#include <boost/range/adaptor/filtered.hpp>
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#include <boost/range/numeric.hpp>
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#include <boost/numeric/odeint/stepper/runge_kutta4.hpp>
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#include <boost/numeric/odeint/stepper/runge_kutta_dopri5.hpp>
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#include <boost/numeric/odeint/stepper/generation.hpp>
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#include <boost/numeric/odeint/iterator/const_step_iterator.hpp>
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#include <boost/numeric/odeint/iterator/const_step_time_iterator.hpp>
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#define tab "\t"
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using namespace std;
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using namespace boost::numeric::odeint;
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const double sigma = 10.0;
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const double R = 28.0;
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const double b = 8.0 / 3.0;
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struct lorenz
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{
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template< class State , class Deriv >
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void operator()( const State &x , Deriv &dxdt , double t ) const
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{
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dxdt[0] = sigma * ( x[1] - x[0] );
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dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
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dxdt[2] = -b * x[2] + x[0] * x[1];
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}
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};
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int main( int argc , char **argv )
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{
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typedef std::array< double , 3 > state_type;
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// std::for_each
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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std::for_each( make_const_step_time_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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make_const_step_time_iterator_end( stepper , lorenz() , x ) ,
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[]( const std::pair< state_type&, double > &x ) {
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std::cout << x.second << tab << x.first[0] << tab << x.first[1] << tab << x.first[2] << "\n"; } );
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}
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// std::copy_if
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{
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std::vector< state_type > res;
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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std::copy_if( make_const_step_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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make_const_step_iterator_end( stepper , lorenz() , x ) ,
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std::back_inserter( res ) ,
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[]( const state_type& x ) {
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return ( x[0] > 0.0 ) ? true : false; } );
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for( size_t i=0 ; i<res.size() ; ++i )
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cout << res[i][0] << tab << res[i][1] << tab << res[i][2] << "\n";
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}
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// std::accumulate
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{
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//[ const_step_iterator_accumulate
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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double res = std::accumulate( make_const_step_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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make_const_step_iterator_end( stepper , lorenz() , x ) ,
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0.0 ,
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[]( double sum , const state_type &x ) {
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return sum + x[0]; } );
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cout << res << endl;
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//]
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}
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// std::transform
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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vector< double > weights;
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std::transform( make_const_step_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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make_const_step_iterator_end( stepper , lorenz() , x ) ,
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back_inserter( weights ) ,
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[]( const state_type &x ) {
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return sqrt( x[0] * x[0] + x[1] * x[1] + x[2] * x[2] ); } );
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for( size_t i=0 ; i<weights.size() ; ++i )
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cout << weights[i] << "\n";
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}
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// std::transform with time_iterator
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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vector< double > weights;
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std::transform( make_const_step_time_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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make_const_step_time_iterator_end( stepper , lorenz() , x ) ,
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back_inserter( weights ) ,
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[]( const std::pair< state_type &, double > &x ) {
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return sqrt( x.first[0] * x.first[0] + x.first[1] * x.first[1] + x.first[2] * x.first[2] ); } );
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for( size_t i=0 ; i<weights.size() ; ++i )
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cout << weights[i] << "\n";
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}
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// /*
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// * Boost.Range versions
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// */
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// boost::range::for_each
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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boost::range::for_each( make_const_step_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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[]( const state_type &x ) {
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std::cout << x[0] << tab << x[1] << tab << x[2] << "\n"; } );
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}
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// boost::range::for_each with time iterator
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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boost::range::for_each( make_const_step_time_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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[]( const std::pair< state_type& , double > &x ) {
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std::cout << x.second << tab << x.first[0] << tab << x.first[1] << tab << x.first[2] << "\n"; } );
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}
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// boost::range::copy with filtered adaptor (simulating std::copy_if)
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{
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std::vector< state_type > res;
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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boost::range::copy( make_const_step_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) |
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boost::adaptors::filtered( [] ( const state_type &x ) { return ( x[0] > 0.0 ); } ) ,
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std::back_inserter( res ) );
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for( size_t i=0 ; i<res.size() ; ++i )
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cout << res[i][0] << tab << res[i][1] << tab << res[i][2] << "\n";
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}
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// boost::range::accumulate
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{
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//[const_step_iterator_accumulate_range
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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double res = boost::accumulate( make_const_step_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) , 0.0 ,
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[]( double sum , const state_type &x ) {
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return sum + x[0]; } );
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cout << res << endl;
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//]
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}
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// boost::range::accumulate with time iterator
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{
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//[const_step_time_iterator_accumulate_range
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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double res = boost::accumulate( make_const_step_time_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) , 0.0 ,
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[]( double sum , const std::pair< state_type &, double > &x ) {
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return sum + x.first[0]; } );
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cout << res << endl;
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//]
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}
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// boost::range::transform
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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vector< double > weights;
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boost::transform( make_const_step_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) , back_inserter( weights ) ,
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[]( const state_type &x ) {
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return sqrt( x[0] * x[0] + x[1] * x[1] + x[2] * x[2] ); } );
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for( size_t i=0 ; i<weights.size() ; ++i )
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cout << weights[i] << "\n";
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}
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// boost::range::find with time iterator
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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auto iter = boost::find_if( make_const_step_time_range( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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[]( const std::pair< state_type & , double > &x ) {
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return ( x.first[0] < 0.0 ); } );
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cout << iter->second << "\t" << iter->first[0] << "\t" << iter->first[1] << "\t" << iter->first[2] << "\n";
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}
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/*
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* Boost.Range versions for dense output steppers
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*/
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// boost::range::for_each
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{
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runge_kutta_dopri5< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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boost::range::for_each( make_const_step_range( make_dense_output( 1.0e-6 , 1.0e-6 , stepper ) , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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[]( const state_type &x ) {
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std::cout << x[0] << tab << x[1] << tab << x[2] << "\n"; } );
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}
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// boost::range::for_each with time iterator
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{
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runge_kutta_dopri5< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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boost::range::for_each( make_const_step_time_range( make_dense_output( 1.0e-6 , 1.0e-6 , stepper ) , lorenz() , x , 0.0 , 1.0 , 0.01 ) ,
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[]( const std::pair< state_type& , double > &x ) {
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std::cout << x.second << tab << x.first[0] << tab << x.first[1] << tab << x.first[2] << "\n"; } );
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}
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/*
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* Pure iterators
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*/
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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auto first = make_const_step_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 );
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auto last = make_const_step_iterator_end( stepper , lorenz() , x );
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while( first != last )
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{
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assert( last != first );
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cout << (*first)[0] << tab << (*first)[1] << tab << (*first)[2] << "\n";
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++first;
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}
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}
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{
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runge_kutta4< state_type > stepper;
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state_type x = {{ 10.0 , 10.0 , 10.0 }};
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auto first = make_const_step_time_iterator_begin( stepper , lorenz() , x , 0.0 , 1.0 , 0.01 );
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auto last = make_const_step_time_iterator_end( stepper , lorenz() , x );
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while( first != last )
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{
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assert( last != first );
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cout << first->second << tab << first->first[0] << tab << first->first[1] << tab << first->first[2] << "\n";
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++first;
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}
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}
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return 0;
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}
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