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- /* Boost libs/numeric/odeint/examples/simple1d.cpp
- Copyright 2012-2013 Mario Mulansky
- Copyright 2012 Karsten Ahnert
- example for a simple one-dimensional 1st order ODE
- 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 <boost/numeric/odeint.hpp>
- using namespace std;
- using namespace boost::numeric::odeint;
- /* we solve the simple ODE x' = 3/(2t^2) + x/(2t)
- * with initial condition x(1) = 0.
- * Analytic solution is x(t) = sqrt(t) - 1/t
- */
- void rhs( const double x , double &dxdt , const double t )
- {
- dxdt = 3.0/(2.0*t*t) + x/(2.0*t);
- }
- void write_cout( const double &x , const double t )
- {
- cout << t << '\t' << x << endl;
- }
- // state_type = double
- typedef runge_kutta_dopri5< double > stepper_type;
- int main()
- {
- double x = 0.0; //initial value x(1) = 0
- // use dopri5 with stepsize control and allowed errors 10^-12, integrate t=1...10
- integrate_adaptive( make_controlled( 1E-12 , 1E-12 , stepper_type() ) , rhs , x , 1.0 , 10.0 , 0.1 , write_cout );
- }
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