backend_omp.hpp

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//============================================================================
// vSMC/include/vsmc/smp/backend_omp.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013-2015, Yan Zhou
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// 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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//============================================================================

#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)
    {
#if _OPENMP < 200805
        using stype = typename std::make_signed<size_type>::type;
        stype n = static_cast<stype>(N);
#pragma omp parallel for default(shared)
        for (stype i = 0; i < n; ++i) {
            this->copy_particle(
                static_cast<size_type>(src_idx[i]), static_cast<size_type>(i));
        }
#else // _OPENMP < 200805
#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);
#endif // _OPENMP < 200805
    }
}; // 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;
#if _OPENMP < 200805
        using stype = typename std::make_signed<size_type>::type;
        stype n = static_cast<stype>(N);
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (stype i = 0; i < n; ++i) {
            accept += this->eval_sp(
                SingleParticle<T>(static_cast<size_type>(i), &particle));
        }
#else // _OPENMP < 200805
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (size_type i = 0; i < N; ++i)
            accept += this->eval_sp(SingleParticle<T>(i, &particle));
#endif // _OPENMP < 200805
        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;
#if _OPENMP < 200805
        using stype = typename std::make_signed<size_type>::type;
        stype n = static_cast<stype>(N);
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (stype i = 0; i < n; ++i) {
            accept += this->eval_sp(
                iter, SingleParticle<T>(static_cast<size_type>(i), &particle));
        }
#else // _OPENMP < 200805
#pragma omp parallel for reduction(+ : accept) default(shared)
        for (size_type i = 0; i < N; ++i)
            accept += this->eval_sp(iter, SingleParticle<T>(i, &particle));
#endif // _OPENMP < 200805
        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);
#if _OPENMP < 200805
        using stype = typename std::make_signed<size_type>::type;
        stype n = static_cast<stype>(N);
#pragma omp parallel for default(shared)
        for (stype i = 0; i < n; ++i) {
            this->eval_sp(iter, dim,
                SingleParticle<T>(static_cast<size_type>(i), &particle),
                r + static_cast<std::size_t>(i) * dim);
        }
#else // _OPENMP < 200805
#pragma omp parallel for default(shared)
        for (size_type i = 0; i < N; ++i) {
            this->eval_sp(iter, dim, SingleParticle<T>(i, &particle),
                r + static_cast<std::size_t>(i) * dim);
        }
#endif // _OPENMP < 200805
        this->eval_post(iter, particle);
    }

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

template <typename T, typename Derived>
class PathEvalOMP : public PathEvalBase<T, Derived>
{
    public:
    double operator()(std::size_t iter, Particle<T> &particle, double *r)
    {
        using size_type = typename Particle<T>::size_type;
        const size_type N = particle.size();
        this->eval_pre(iter, particle);
#if _OPENMP < 200805
        using stype = typename std::make_signed<size_type>::type;
        stype n = static_cast<stype>(N);
#pragma omp parallel for default(shared)
        for (stype i = 0; i < n; ++i) {
            r[i] = this->eval_sp(
                iter, SingleParticle<T>(static_cast<size_type>(i), &particle));
        }
#else // _OPENMP < 200805
#pragma omp parallel for default(shared)
        for (size_type i = 0; i < N; ++i)
            r[i] = this->eval_sp(iter, SingleParticle<T>(i, &particle));
#endif // _OPENMP < 200805
        this->eval_post(iter, particle);

        return this->eval_grid(iter, particle);
    }

    protected:
    VSMC_DEFINE_SMP_BACKEND_SPECIAL(OMP, PathEval)
}; // class PathEvalOMP

} // namespace vsmc

#endif // VSMC_SMP_BACKEND_OMP_HPP