rng_set.hpp

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//============================================================================
// vSMC/include/vsmc/rng/rng_set.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013,2014, 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
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS AS IS
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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//============================================================================

#ifndef VSMC_RNG_RNG_SET_HPP
#define VSMC_RNG_RNG_SET_HPP

#include <vsmc/rng/internal/common.hpp>
#include <vsmc/rng/seed.hpp>
#if VSMC_HAS_AES_NI
#include <vsmc/rng/aes.hpp>
#include <vsmc/rng/ars.hpp>
#endif
#include <vsmc/rng/philox.hpp>
#include <vsmc/rng/threefry.hpp>

#ifndef VSMC_RNG_SET_TYPE
#define VSMC_RNG_SET_TYPE ::vsmc::RngSet< ::vsmc::Threefry4x64, ::vsmc::Vector>
#endif

namespace vsmc {

template <typename = Threefry4x64, typename = Vector> class RngSet;

template <typename RngType>
class RngSet<RngType, Scalar>
{
    public :

    typedef RngType rng_type;
    typedef std::size_t size_type;

    explicit RngSet (size_type N = 0) : size_(N) {seed();}

    size_type size () const {return size_;}

    void resize (std::size_t) {}

    void seed () {rng_.seed(Seed::instance().get());}

    rng_type &operator[] (size_type) {return rng_;}

    private :

    std::size_t size_;
    rng_type rng_;
}; // class RngSet

template <typename RngType>
class RngSet<RngType, Vector>
{
    public :

    typedef RngType rng_type;
    typedef typename std::vector<rng_type, AlignedAllocator<rng_type> >::
        size_type size_type;

    explicit RngSet (size_type N = 0) : rng_(N, rng_type()) {seed();}

    size_type size () const {return rng_.size();}

    void resize (std::size_t n)
    {
        if (n == rng_.size())
            return;

        if (n < rng_.size())
            rng_.resize(n);

        rng_.reserve(n);
        rng_type rng;
        for (std::size_t i = rng_.size(); i != n; ++i) {
            rng.seed(Seed::instance().get());
            rng_.push_back(rng);
        }
    }

    void seed ()
    {
        for (size_type i = 0; i != rng_.size(); ++i)
            rng_[i].seed(Seed::instance().get());
    }

    rng_type &operator[] (size_type id) {return rng_[id];}

    private :

    std::vector<rng_type, AlignedAllocator<rng_type> > rng_;
}; // class RngSet

namespace traits {

VSMC_DEFINE_TYPE_DISPATCH_TRAIT(RngSetType, rng_set_type, VSMC_RNG_SET_TYPE)

} // namespace vsmc::traits

} // namespace vsmc

#endif // VSMC_RNG_RNG_SET_HPP