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- /*
- * elliptic_functions.cpp
- *
- * Copyright 2011-2013 Mario Mulansky
- * Copyright 2011-2012 Karsten Ahnert
- *
- * Distributed under the Boost Software License, Version 1.0.
- * (See accompanying file LICENSE_1_0.txt or
- * copy at http://www.boost.org/LICENSE_1_0.txt)
- */
- #include <iostream>
- #include <fstream>
- #include <cmath>
- #include <boost/array.hpp>
- #include <boost/numeric/odeint/config.hpp>
- #include <boost/numeric/odeint.hpp>
- #include <boost/numeric/odeint/stepper/bulirsch_stoer.hpp>
- #include <boost/numeric/odeint/stepper/bulirsch_stoer_dense_out.hpp>
- using namespace std;
- using namespace boost::numeric::odeint;
- typedef boost::array< double , 3 > state_type;
- /*
- * x1' = x2*x3
- * x2' = -x1*x3
- * x3' = -m*x1*x2
- */
- void rhs( const state_type &x , state_type &dxdt , const double t )
- {
- static const double m = 0.51;
- dxdt[0] = x[1]*x[2];
- dxdt[1] = -x[0]*x[2];
- dxdt[2] = -m*x[0]*x[1];
- }
- ofstream out;
- void write_out( const state_type &x , const double t )
- {
- out << t << '\t' << x[0] << '\t' << x[1] << '\t' << x[2] << endl;
- }
- int main()
- {
- bulirsch_stoer_dense_out< state_type > stepper( 1E-9 , 1E-9 , 1.0 , 0.0 );
- state_type x1 = {{ 0.0 , 1.0 , 1.0 }};
- double t = 0.0;
- double dt = 0.01;
- out.open( "elliptic1.dat" );
- out.precision(16);
- integrate_const( stepper , rhs , x1 , t , 100.0 , dt , write_out );
- out.close();
- state_type x2 = {{ 0.0 , 1.0 , 1.0 }};
- out.open( "elliptic2.dat" );
- out.precision(16);
- integrate_adaptive( stepper , rhs , x2 , t , 100.0 , dt , write_out );
- out.close();
- typedef runge_kutta_dopri5< state_type > dopri5_type;
- typedef controlled_runge_kutta< dopri5_type > controlled_dopri5_type;
- typedef dense_output_runge_kutta< controlled_dopri5_type > dense_output_dopri5_type;
- dense_output_dopri5_type dopri5 = make_dense_output( 1E-9 , 1E-9 , dopri5_type() );
- //dense_output_dopri5_type dopri5( controlled_dopri5_type( default_error_checker< double >( 1E-9 , 0.0 , 0.0 , 0.0 ) ) );
- state_type x3 = {{ 0.0 , 1.0 , 1.0 }};
- out.open( "elliptic3.dat" );
- out.precision(16);
- integrate_adaptive( dopri5 , rhs , x3 , t , 100.0 , dt , write_out );
- out.close();
- }
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