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https://github.com/saitohirga/WSJT-X.git
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121 lines
3.3 KiB
C++
121 lines
3.3 KiB
C++
/*
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* phase_chain.cpp
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*
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* Example of MPI parallelization with odeint
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*
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* Copyright 2013 Karsten Ahnert
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* Copyright 2013 Mario Mulansky
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* Copyright 2013 Pascal Germroth
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* Distributed under the Boost Software License, Version 1.0. (See
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* accompanying file LICENSE_1_0.txt or copy at
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* http://www.boost.org/LICENSE_1_0.txt)
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*/
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#include <iostream>
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#include <vector>
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#include <boost/random.hpp>
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#include <boost/timer/timer.hpp>
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//[phase_chain_mpi_header
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#include <boost/numeric/odeint.hpp>
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#include <boost/numeric/odeint/external/mpi/mpi.hpp>
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//]
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using namespace std;
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using namespace boost::numeric::odeint;
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using boost::timer::cpu_timer;
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using boost::math::double_constants::pi;
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//[phase_chain_state
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typedef mpi_state< vector<double> > state_type;
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//]
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//[phase_chain_mpi_rhs
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struct phase_chain_mpi_state
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{
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phase_chain_mpi_state( double gamma = 0.5 )
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: m_gamma( gamma ) { }
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void operator()( const state_type &x , state_type &dxdt , double /* t */ ) const
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{
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const size_t M = x().size();
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const bool have_left = x.world.rank() > 0,
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have_right = x.world.rank() < x.world.size()-1;
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double x_left, x_right;
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boost::mpi::request r_left, r_right;
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if( have_left )
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{
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x.world.isend( x.world.rank()-1 , 0 , x().front() ); // send to x_right
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r_left = x.world.irecv( x.world.rank()-1 , 0 , x_left ); // receive from x().back()
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}
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if( have_right )
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{
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x.world.isend( x.world.rank()+1 , 0 , x().back() ); // send to x_left
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r_right = x.world.irecv( x.world.rank()+1 , 0 , x_right ); // receive from x().front()
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}
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for(size_t m = 1 ; m < M-1 ; ++m)
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{
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dxdt()[m] = coupling_func( x()[m+1] - x()[m] ) +
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coupling_func( x()[m-1] - x()[m] );
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}
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dxdt()[0] = coupling_func( x()[1] - x()[0] );
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if( have_left )
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{
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r_left.wait();
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dxdt()[0] += coupling_func( x_left - x().front() );
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}
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dxdt()[M-1] = coupling_func( x()[M-2] - x()[M-1] );
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if( have_right )
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{
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r_right.wait();
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dxdt()[M-1] += coupling_func( x_right - x().back() );
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}
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}
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double coupling_func( double x ) const
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{
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return sin( x ) - m_gamma * ( 1.0 - cos( x ) );
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}
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double m_gamma;
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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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//[phase_chain_mpi_init
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boost::mpi::environment env( argc , argv );
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boost::mpi::communicator world;
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const size_t N = 131101;
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vector<double> x;
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if( world.rank() == 0 )
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{
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x.resize( N );
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boost::random::uniform_real_distribution<double> distribution( 0.0 , 2.0*pi );
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boost::random::mt19937 engine( 0 );
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generate( x.begin() , x.end() , boost::bind( distribution , engine ) );
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}
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state_type x_split( world );
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split( x , x_split );
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//]
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cpu_timer timer;
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//[phase_chain_mpi_integrate
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integrate_n_steps( runge_kutta4<state_type>() , phase_chain_mpi_state( 1.2 ) ,
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x_split , 0.0 , 0.01 , 100 );
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unsplit( x_split , x );
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//]
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if( world.rank() == 0 )
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{
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double run_time = static_cast<double>(timer.elapsed().wall) * 1.0e-9;
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std::cerr << run_time << "s" << std::endl;
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// copy(x.begin(), x.end(), ostream_iterator<double>(cout, "\n"));
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}
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return 0;
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}
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