backend_omp.hpp

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//============================================================================
// vSMC/include/vsmc/smp/backend_omp.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013-2016, Yan Zhou
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are met:
//
//   Redistributions of source code must retain the above copyright notice,
//   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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//
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// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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//============================================================================

#ifndef VSMC_SMP_BACKEND_OMP_HPP
#define VSMC_SMP_BACKEND_OMP_HPP

#include <vsmc/smp/backend_base.hpp>
#include <omp.h>

namespace vsmc
{

VSMC_DEFINE_SMP_BACKEND_FORWARD(OMP)

template <typename StateBase>
class StateOMP : public StateBase
{
    public:
    using size_type = SizeType<StateBase>;

    explicit StateOMP(size_type N) : StateBase(N) {}

    template <typename IntType>
    void copy(size_type N, const IntType *src_idx)
    {
#pragma omp parallel for default(shared)
        for (size_type i = 0; i < N; ++i)
            this->copy_particle(static_cast<size_type>(src_idx[i]), i);
    }
}; // class StateOMP

template <typename T, typename Derived>
class InitializeOMP : public InitializeBase<T, Derived>
{
    public:
    std::size_t operator()(Particle<T> &particle, void *param)
    {
        using size_type = typename Particle<T>::size_type;
        const size_type N = particle.size();
        this->eval_param(particle, param);
        this->eval_pre(particle);
        std::size_t accept = 0;
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (size_type i = 0; i < N; ++i)
            accept += this->eval_sp(particle.sp(i));
        this->eval_post(particle);

        return accept;
    }

    protected:
    VSMC_DEFINE_SMP_BACKEND_SPECIAL(OMP, Initialize)
}; // class InitializeOMP

template <typename T, typename Derived>
class MoveOMP : public MoveBase<T, Derived>
{
    public:
    std::size_t operator()(std::size_t iter, Particle<T> &particle)
    {
        using size_type = typename Particle<T>::size_type;
        const size_type N = particle.size();
        this->eval_pre(iter, particle);
        std::size_t accept = 0;
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (size_type i = 0; i < N; ++i)
            accept += this->eval_sp(iter, particle.sp(i));
        this->eval_post(iter, particle);

        return accept;
    }

    protected:
    VSMC_DEFINE_SMP_BACKEND_SPECIAL(OMP, Move)
}; // class MoveOMP

template <typename T, typename Derived>
class MonitorEvalOMP : public MonitorEvalBase<T, Derived>
{
    public:
    void operator()(
        std::size_t iter, std::size_t dim, Particle<T> &particle, double *r)
    {
        using size_type = typename Particle<T>::size_type;
        const size_type N = particle.size();
        this->eval_pre(iter, particle);
#pragma omp parallel for default(shared)
        for (size_type i = 0; i < N; ++i) {
            this->eval_sp(iter, dim, particle.sp(i),
                r + static_cast<std::size_t>(i) * dim);
        }
        this->eval_post(iter, particle);
    }

    protected:
    VSMC_DEFINE_SMP_BACKEND_SPECIAL(OMP, MonitorEval)
}; // class MonitorEvalOMP

} // namespace vsmc

#endif // VSMC_SMP_BACKEND_OMP_HPP