84 lines
1.8 KiB
C++
84 lines
1.8 KiB
C++
/*
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* lorenz_gmpxx.cpp
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*
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* This example demonstrates how odeint can be used with arbitrary precision types.
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*
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* Copyright 2011-2012 Karsten Ahnert
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* Copyright 2011-2012 Mario Mulansky
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*
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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/array.hpp>
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#include <gmpxx.h>
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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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//[ gmpxx_lorenz
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typedef mpf_class value_type;
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typedef boost::array< value_type , 3 > state_type;
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struct lorenz
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{
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void operator()( const state_type &x , state_type &dxdt , value_type t ) const
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{
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const value_type sigma( 10.0 );
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const value_type R( 28.0 );
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const value_type b( value_type( 8.0 ) / value_type( 3.0 ) );
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dxdt[0] = sigma * ( x[1] - x[0] );
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dxdt[1] = R * x[0] - x[1] - x[0] * x[2];
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dxdt[2] = -b * x[2] + x[0] * x[1];
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}
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};
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//]
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struct streaming_observer
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{
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std::ostream& m_out;
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streaming_observer( std::ostream &out ) : m_out( out ) { }
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template< class State , class Time >
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void operator()( const State &x , Time t ) const
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{
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m_out << t;
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for( size_t i=0 ; i<x.size() ; ++i ) m_out << "\t" << x[i] ;
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m_out << "\n";
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}
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};
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int main( int argc , char **argv )
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{
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//[ gmpxx_integration
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const int precision = 1024;
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mpf_set_default_prec( precision );
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state_type x = {{ value_type( 10.0 ) , value_type( 10.0 ) , value_type( 10.0 ) }};
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cout.precision( 1000 );
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integrate_const( runge_kutta4< state_type , value_type >() ,
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lorenz() , x , value_type( 0.0 ) , value_type( 10.0 ) , value_type( value_type( 1.0 ) / value_type( 10.0 ) ) ,
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streaming_observer( cout ) );
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//]
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return 0;
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}
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