55 lines
1.4 KiB
C++
55 lines
1.4 KiB
C++
/* Boost libs/numeric/odeint/examples/integrate_times.cpp
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Copyright 2009-2014 Karsten Ahnert
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Copyright 2009-2014 Mario Mulansky
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example for the use of integrate_times
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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 <boost/numeric/odeint.hpp>
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using namespace std;
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using namespace boost::numeric::odeint;
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/*
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* simple 1D ODE
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*/
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void rhs( const double x , double &dxdt , const double t )
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{
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dxdt = 3.0/(2.0*t*t) + x/(2.0*t);
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}
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void write_cout( const double &x , const double t )
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{
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cout << t << '\t' << x << endl;
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}
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// state_type = double
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typedef runge_kutta_dopri5< double > stepper_type;
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const double dt = 0.1;
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int main()
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{
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// create a vector with observation time points
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std::vector<double> times( 91 );
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for( size_t i=0 ; i<times.size() ; ++i )
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times[i] = 1.0 + dt*i;
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double x = 0.0; //initial value x(1) = 0
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// we can provide the observation time as a boost range (i.e. the vector)
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integrate_times( make_controlled( 1E-12 , 1E-12 , stepper_type() ) , rhs ,
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x , times , dt , write_cout );
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// or as two iterators
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//integrate_times( make_controlled( 1E-12 , 1E-12 , stepper_type() ) , rhs ,
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// x , times.begin() , times.end() , dt , write_cout );
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}
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