mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2025-11-04 05:50:31 -05:00
96 lines
2.5 KiB
C++
96 lines
2.5 KiB
C++
/*
|
|
* phase_chain.cpp
|
|
*
|
|
* Example of OMP parallelization with odeint
|
|
*
|
|
* Copyright 2013 Karsten Ahnert
|
|
* Copyright 2013 Mario Mulansky
|
|
* Copyright 2013 Pascal Germroth
|
|
* 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 <vector>
|
|
#include <boost/random.hpp>
|
|
#include <boost/timer/timer.hpp>
|
|
//[phase_chain_openmp_header
|
|
#include <omp.h>
|
|
#include <boost/numeric/odeint.hpp>
|
|
#include <boost/numeric/odeint/external/openmp/openmp.hpp>
|
|
//]
|
|
|
|
using namespace std;
|
|
using namespace boost::numeric::odeint;
|
|
using boost::timer::cpu_timer;
|
|
using boost::math::double_constants::pi;
|
|
|
|
//[phase_chain_vector_state
|
|
typedef std::vector< double > state_type;
|
|
//]
|
|
|
|
//[phase_chain_rhs
|
|
struct phase_chain
|
|
{
|
|
phase_chain( double gamma = 0.5 )
|
|
: m_gamma( gamma ) { }
|
|
|
|
void operator()( const state_type &x , state_type &dxdt , double /* t */ ) const
|
|
{
|
|
const size_t N = x.size();
|
|
#pragma omp parallel for schedule(runtime)
|
|
for(size_t i = 1 ; i < N - 1 ; ++i)
|
|
{
|
|
dxdt[i] = coupling_func( x[i+1] - x[i] ) +
|
|
coupling_func( x[i-1] - x[i] );
|
|
}
|
|
dxdt[0 ] = coupling_func( x[1 ] - x[0 ] );
|
|
dxdt[N-1] = coupling_func( x[N-2] - x[N-1] );
|
|
}
|
|
|
|
double coupling_func( double x ) const
|
|
{
|
|
return sin( x ) - m_gamma * ( 1.0 - cos( x ) );
|
|
}
|
|
|
|
double m_gamma;
|
|
};
|
|
//]
|
|
|
|
|
|
int main( int argc , char **argv )
|
|
{
|
|
//[phase_chain_init
|
|
size_t N = 131101;
|
|
state_type x( N );
|
|
boost::random::uniform_real_distribution<double> distribution( 0.0 , 2.0*pi );
|
|
boost::random::mt19937 engine( 0 );
|
|
generate( x.begin() , x.end() , boost::bind( distribution , engine ) );
|
|
//]
|
|
|
|
//[phase_chain_stepper
|
|
typedef runge_kutta4<
|
|
state_type , double ,
|
|
state_type , double ,
|
|
openmp_range_algebra
|
|
> stepper_type;
|
|
//]
|
|
|
|
//[phase_chain_scheduling
|
|
int chunk_size = N/omp_get_max_threads();
|
|
omp_set_schedule( omp_sched_static , chunk_size );
|
|
//]
|
|
|
|
cpu_timer timer;
|
|
//[phase_chain_integrate
|
|
integrate_n_steps( stepper_type() , phase_chain( 1.2 ) ,
|
|
x , 0.0 , 0.01 , 100 );
|
|
//]
|
|
double run_time = static_cast<double>(timer.elapsed().wall) * 1.0e-9;
|
|
std::cerr << run_time << "s" << std::endl;
|
|
// copy(x.begin(), x.end(), ostream_iterator<double>(cout, "\n"));
|
|
|
|
return 0;
|
|
}
|