parallel_reduce.hpp

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//============================================================================
// vSMC/include/vsmc/thread/parallel_reduce.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013,2014, Yan Zhou
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
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//   this list of conditions and the following disclaimer.
//
//   Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
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//============================================================================

#ifndef VSMC_THREAD_PARALLEL_REDUCE_HPP
#define VSMC_THREAD_PARALLEL_REDUCE_HPP

#include <vsmc/internal/common.hpp>
#include <vsmc/thread/blocked_range.hpp>
#include <vsmc/thread/thread_guard.hpp>
#include <vsmc/thread/thread_num.hpp>
#include <thread>

namespace vsmc {

template <typename Range, typename WorkType>
inline void parallel_reduce (const Range &range, WorkType &work)
{
    std::vector<Range> range_vec(ThreadNum::instance().partition(range));
    std::vector<WorkType> work_vec(range_vec.size(), work);
    {
        std::vector<ThreadGuard<std::thread>> tg;
        tg.reserve(range_vec.size());
        for (std::size_t i = 0; i != range_vec.size(); ++i) {
            tg.push_back(ThreadGuard<std::thread>(std::thread(
                            std::ref(work_vec[i]), range_vec[i])));
        }
    }
    for (std::size_t i = 0; i != work_vec.size(); ++i) work.join(work_vec[i]);
}

} // namespace vsmc

#endif // VSMC_THREAD_PARALLEL_REDUCE_HPP