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- /*
- * van_der_pol_stiff.cpp
- *
- * Created on: Dec 12, 2011
- *
- * Copyright 2012 Karsten Ahnert
- * Copyright 2012-2013 Rajeev Singh
- * Copyright 2012-2013 Mario Mulansky
- *
- * 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 <utility>
- #include <boost/numeric/odeint.hpp>
- #include <boost/phoenix/core.hpp>
- #include <boost/phoenix/operator.hpp>
- using namespace std;
- using namespace boost::numeric::odeint;
- namespace phoenix = boost::phoenix;
- const double mu = 1000.0;
- typedef boost::numeric::ublas::vector< double > vector_type;
- typedef boost::numeric::ublas::matrix< double > matrix_type;
- struct vdp_stiff
- {
- void operator()( const vector_type &x , vector_type &dxdt , double t )
- {
- dxdt[0] = x[1];
- dxdt[1] = -x[0] - mu * x[1] * (x[0]*x[0]-1.0);
- }
- };
- struct vdp_stiff_jacobi
- {
- void operator()( const vector_type &x , matrix_type &J , const double &t , vector_type &dfdt )
- {
- J(0, 0) = 0.0;
- J(0, 1) = 1.0;
- J(1, 0) = -1.0 - 2.0*mu * x[0] * x[1];
- J(1, 1) = -mu * ( x[0] * x[0] - 1.0);
- dfdt[0] = 0.0;
- dfdt[1] = 0.0;
- }
- };
- int main( int argc , char **argv )
- {
- //[ integrate_stiff_system
- vector_type x( 2 );
- /* initialize random seed: */
- srand ( time(NULL) );
- // initial conditions
- for (int i=0; i<2; i++)
- x[i] = 1.0; //(1.0 * rand()) / RAND_MAX;
- size_t num_of_steps = integrate_const( make_dense_output< rosenbrock4< double > >( 1.0e-6 , 1.0e-6 ) ,
- make_pair( vdp_stiff() , vdp_stiff_jacobi() ) ,
- x , 0.0 , 1000.0 , 1.0
- , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n"
- );
- //]
- clog << num_of_steps << endl;
- //[ integrate_stiff_system_alternative
- vector_type x2( 2 );
- // initial conditions
- for (int i=0; i<2; i++)
- x2[i] = 1.0; //(1.0 * rand()) / RAND_MAX;
- //size_t num_of_steps2 = integrate_const( make_dense_output< runge_kutta_dopri5< vector_type > >( 1.0e-6 , 1.0e-6 ) ,
- // vdp_stiff() , x2 , 0.0 , 1000.0 , 1.0
- // , cout << phoenix::arg_names::arg2 << " " << phoenix::arg_names::arg1[0] << " " << phoenix::arg_names::arg1[1] << "\n"
- // );
- //]
- //clog << num_of_steps2 << endl;
- return 0;
- }
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