mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-11-04 05:50:31 -05:00
45 lines
1.1 KiB
C++
45 lines
1.1 KiB
C++
|
/* 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 );
|
||
|
|
}
|