ceph/src/boost/libs/numeric/odeint/examples/lorenz.cpp

   1 #include <iostream>
   2 #include <boost/array.hpp>
   3
   4 #include <boost/numeric/odeint.hpp>
   5
   6 using namespace std;
   7 using namespace boost::numeric::odeint;
   8
   9 const double sigma = 10.0;
  10 const double R = 28.0;
  11 const double b = 8.0 / 3.0;
  12
  13 typedef boost::array< double , 3 > state_type;
  14
  15 void lorenz( const state_type &x , state_type &dxdt , double t )
  16 {
  17     dxdt[0] = sigma * ( x[1] - x[0] );
  18     dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
  19     dxdt[2] = -b * x[2] + x[0] * x[1];
  20 }
  21
  22 void write_lorenz( const state_type &x , const double t )
  23 {
  24     cout << t << '\t' << x[0] << '\t' << x[1] << '\t' << x[2] << endl;
  25 }
  26
  27 int main(int argc, char **argv)
  28 {
  29     state_type x = {{ 10.0 , 1.0 , 1.0 }}; // initial conditions
  30     integrate( lorenz , x , 0.0 , 25.0 , 0.1 , write_lorenz );
  31 }