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/*
* stuart_landau.cpp
*
* This example demonstrates how one can use odeint can be used with state types consisting of complex variables.
*
* Copyright 2011-2012 Karsten Ahnert
* Copyright 2011-2013 Mario Mulansky
* 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 <complex>
#include <boost/array.hpp>
#include <boost/numeric/odeint.hpp>
using namespace std;
using namespace boost::numeric::odeint;
//[ stuart_landau_system_function
typedef complex< double > state_type;
struct stuart_landau
{
double m_eta;
double m_alpha;
stuart_landau( double eta = 1.0 , double alpha = 1.0 )
: m_eta( eta ) , m_alpha( alpha ) { }
void operator()( const state_type &x , state_type &dxdt , double t ) const
{
const complex< double > I( 0.0 , 1.0 );
dxdt = ( 1.0 + m_eta * I ) * x - ( 1.0 + m_alpha * I ) * norm( x ) * x;
}
};
//]
/*
//[ stuart_landau_system_function_alternative
double eta = 1.0;
double alpha = 1.0;
void stuart_landau( const state_type &x , state_type &dxdt , double t )
{
const complex< double > I( 0.0 , 1.0 );
dxdt = ( 1.0 + m_eta * I ) * x - ( 1.0 + m_alpha * I ) * norm( x ) * x;
}
//]
*/
struct streaming_observer
{
std::ostream& m_out;
streaming_observer( std::ostream &out ) : m_out( out ) { }
template< class State >
void operator()( const State &x , double t ) const
{
m_out << t;
m_out << "\t" << x.real() << "\t" << x.imag() ;
m_out << "\n";
}
};
int main( int argc , char **argv )
{
//[ stuart_landau_integration
state_type x = complex< double >( 1.0 , 0.0 );
const double dt = 0.1;
typedef runge_kutta4< state_type > stepper_type;
integrate_const( stepper_type() , stuart_landau( 2.0 , 1.0 ) , x , 0.0 , 10.0 , dt , streaming_observer( cout ) );
//]
return 0;
}
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