1 /*
2 * lorenz_gmpxx.cpp
3 *
4 * This example demonstrates how odeint can be used with arbitrary precision types.
5 *
6 * Copyright 2011-2012 Karsten Ahnert
7 * Copyright 2011-2012 Mario Mulansky
8 *
9 * Distributed under the Boost Software License, Version 1.0.
10 * (See accompanying file LICENSE_1_0.txt or
11 * copy at http://www.boost.org/LICENSE_1_0.txt)
12 */
13
14
15
16 #include <iostream>
17 #include <boost/array.hpp>
18
19 #include <gmpxx.h>
20
21 #include <boost/numeric/odeint.hpp>
22
23 using namespace std;
24 using namespace boost::numeric::odeint;
25
26 //[ gmpxx_lorenz
27 typedef mpf_class value_type;
28 typedef boost::array< value_type , 3 > state_type;
29
30 struct lorenz
31 {
operator ()lorenz32 void operator()( const state_type &x , state_type &dxdt , value_type t ) const
33 {
34 const value_type sigma( 10.0 );
35 const value_type R( 28.0 );
36 const value_type b( value_type( 8.0 ) / value_type( 3.0 ) );
37
38 dxdt[0] = sigma * ( x[1] - x[0] );
39 dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
40 dxdt[2] = -b * x[2] + x[0] * x[1];
41 }
42 };
43 //]
44
45
46
47
48 struct streaming_observer
49 {
50 std::ostream& m_out;
51
streaming_observerstreaming_observer52 streaming_observer( std::ostream &out ) : m_out( out ) { }
53
54 template< class State , class Time >
operator ()streaming_observer55 void operator()( const State &x , Time t ) const
56 {
57 m_out << t;
58 for( size_t i=0 ; i<x.size() ; ++i ) m_out << "\t" << x[i] ;
59 m_out << "\n";
60 }
61 };
62
63
64
65
66
67
main(int argc,char ** argv)68 int main( int argc , char **argv )
69 {
70 //[ gmpxx_integration
71 const int precision = 1024;
72 mpf_set_default_prec( precision );
73
74 state_type x = {{ value_type( 10.0 ) , value_type( 10.0 ) , value_type( 10.0 ) }};
75
76 cout.precision( 1000 );
77 integrate_const( runge_kutta4< state_type , value_type >() ,
78 lorenz() , x , value_type( 0.0 ) , value_type( 10.0 ) , value_type( value_type( 1.0 ) / value_type( 10.0 ) ) ,
79 streaming_observer( cout ) );
80 //]
81
82 return 0;
83 }
84