mirror of
https://github.com/bolero-MURAKAMI/Sprout.git
synced 2024-11-29 01:03:45 +00:00
170 lines
7.4 KiB
C++
170 lines
7.4 KiB
C++
/*=============================================================================
|
|
Copyright (c) 2011-2017 Bolero MURAKAMI
|
|
https://github.com/bolero-MURAKAMI/Sprout
|
|
|
|
Distributed under the Boost Software License, Version 1.0. (See accompanying
|
|
file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
|
=============================================================================*/
|
|
#ifndef SPROUT_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP
|
|
#define SPROUT_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP
|
|
|
|
#include <istream>
|
|
#include <ostream>
|
|
#include <sprout/config.hpp>
|
|
#include <sprout/detail/integer/integer_mask.hpp>
|
|
#include <sprout/random/detail/seed_impl.hpp>
|
|
#include <sprout/random/random_result.hpp>
|
|
#include <sprout/random/type_traits.hpp>
|
|
#include <sprout/type_traits/enabler_if.hpp>
|
|
|
|
namespace sprout {
|
|
namespace random {
|
|
//
|
|
// linear_feedback_shift_engine
|
|
//
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
class linear_feedback_shift_engine {
|
|
public:
|
|
typedef UIntType result_type;
|
|
private:
|
|
struct private_construct_t {};
|
|
public:
|
|
SPROUT_STATIC_CONSTEXPR int word_size = w;
|
|
SPROUT_STATIC_CONSTEXPR int exponent1 = k;
|
|
SPROUT_STATIC_CONSTEXPR int exponent2 = q;
|
|
SPROUT_STATIC_CONSTEXPR int step_size = s;
|
|
SPROUT_STATIC_CONSTEXPR result_type default_seed = 341;
|
|
public:
|
|
static_assert(w > 0, "w > 0");
|
|
static_assert(q > 0, "q > 0");
|
|
static_assert(k < w, "k < w");
|
|
static_assert(0 < 2 * q && 2 * q < k, "0 < 2 * q && 2 * q < k");
|
|
static_assert(0 < s && s <= k - q, "0 < s && s <= k - q");
|
|
public:
|
|
static SPROUT_CONSTEXPR result_type static_min() SPROUT_NOEXCEPT {
|
|
return 0;
|
|
}
|
|
static SPROUT_CONSTEXPR result_type static_max() SPROUT_NOEXCEPT {
|
|
return wordmask();
|
|
}
|
|
private:
|
|
static SPROUT_CONSTEXPR result_type wordmask() {
|
|
return sprout::detail::low_bits_mask_t<w>::sig_bits;
|
|
}
|
|
static SPROUT_CONSTEXPR result_type init_seed_1(result_type x0) {
|
|
return x0 < (1 << (w - k)) ? x0 + (1 << (w - k)) : x0;
|
|
}
|
|
static SPROUT_CONSTEXPR result_type init_seed(result_type x0 = default_seed) {
|
|
return init_seed_1(x0 & wordmask());
|
|
}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
static SPROUT_CXX14_CONSTEXPR result_type init_seed(Sseq& seq) {
|
|
return init_seed(sprout::random::detail::seed_one_int<result_type, (result_type(2) << (w - 1))>(seq));
|
|
}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
static SPROUT_CONSTEXPR result_type init_seed(Sseq const& seq) {
|
|
return init_seed(sprout::random::detail::seed_one_int<result_type, (result_type(2) << (w - 1))>(seq));
|
|
}
|
|
template<typename InputIterator>
|
|
static SPROUT_CONSTEXPR result_type init_seed(InputIterator first, InputIterator last) {
|
|
return init_seed(sprout::random::detail::get_one_int<result_type, (result_type(2) << (w - 1))>(first, last));
|
|
}
|
|
private:
|
|
result_type x_;
|
|
private:
|
|
SPROUT_CONSTEXPR linear_feedback_shift_engine(result_type x, private_construct_t)
|
|
: x_(x)
|
|
{}
|
|
SPROUT_CONSTEXPR sprout::random::random_result<linear_feedback_shift_engine> generate(result_type result) const {
|
|
return sprout::random::random_result<linear_feedback_shift_engine>(
|
|
result,
|
|
linear_feedback_shift_engine(result, private_construct_t())
|
|
);
|
|
}
|
|
public:
|
|
SPROUT_CONSTEXPR linear_feedback_shift_engine()
|
|
: x_(init_seed(default_seed))
|
|
{}
|
|
linear_feedback_shift_engine(linear_feedback_shift_engine const&) = default;
|
|
explicit SPROUT_CONSTEXPR linear_feedback_shift_engine(result_type x0)
|
|
: x_(init_seed(x0))
|
|
{}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
explicit SPROUT_CXX14_CONSTEXPR linear_feedback_shift_engine(Sseq& seq)
|
|
: x_(init_seed(seq))
|
|
{}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
explicit SPROUT_CONSTEXPR linear_feedback_shift_engine(Sseq const& seq)
|
|
: x_(init_seed(seq))
|
|
{}
|
|
template<typename InputIterator>
|
|
SPROUT_CONSTEXPR linear_feedback_shift_engine(InputIterator first, InputIterator last)
|
|
: x_(init_seed(first, last))
|
|
{}
|
|
SPROUT_CXX14_CONSTEXPR void seed(result_type x0 = default_seed) {
|
|
x_ = init_seed(x0);
|
|
}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
SPROUT_CXX14_CONSTEXPR void seed(Sseq& seq) {
|
|
x_ = init_seed(seq);
|
|
}
|
|
template<typename Sseq, typename sprout::enabler_if<sprout::random::is_seed_seq<Sseq>::value>::type = sprout::enabler>
|
|
SPROUT_CXX14_CONSTEXPR void seed(Sseq const& seq) {
|
|
x_ = init_seed(seq);
|
|
}
|
|
template<typename InputIterator>
|
|
SPROUT_CXX14_CONSTEXPR void seed(InputIterator first, InputIterator last) {
|
|
x_ = init_seed(first, last);
|
|
}
|
|
SPROUT_CONSTEXPR result_type min() const SPROUT_NOEXCEPT {
|
|
return static_min();
|
|
}
|
|
SPROUT_CONSTEXPR result_type max() const SPROUT_NOEXCEPT {
|
|
return static_max();
|
|
}
|
|
SPROUT_CXX14_CONSTEXPR result_type operator()() {
|
|
x_ = ((x_ & ((wordmask() << (w - k)) & wordmask())) << s) ^ ((((x_ << q) ^ x_) & wordmask()) >> (k - s));
|
|
return x_;
|
|
}
|
|
SPROUT_CONSTEXPR sprout::random::random_result<linear_feedback_shift_engine> const operator()() const {
|
|
return generate(((x_ & ((wordmask() << (w - k)) & wordmask())) << s) ^ ((((x_ << q) ^ x_) & wordmask()) >> (k - s)));
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator==(linear_feedback_shift_engine const& lhs, linear_feedback_shift_engine const& rhs) SPROUT_NOEXCEPT {
|
|
return lhs.x_ == rhs.x_;
|
|
}
|
|
friend SPROUT_CONSTEXPR bool operator!=(linear_feedback_shift_engine const& lhs, linear_feedback_shift_engine const& rhs) SPROUT_NOEXCEPT {
|
|
return !(lhs == rhs);
|
|
}
|
|
template<typename Elem, typename Traits>
|
|
friend SPROUT_NON_CONSTEXPR std::basic_istream<Elem, Traits>& operator>>(
|
|
std::basic_istream<Elem, Traits>& lhs,
|
|
linear_feedback_shift_engine& rhs
|
|
)
|
|
{
|
|
return lhs >> rhs.x_;
|
|
}
|
|
template<typename Elem, typename Traits>
|
|
friend SPROUT_NON_CONSTEXPR std::basic_ostream<Elem, Traits>& operator<<(
|
|
std::basic_ostream<Elem, Traits>& lhs,
|
|
linear_feedback_shift_engine const& rhs
|
|
)
|
|
{
|
|
return lhs << rhs.x_;
|
|
}
|
|
};
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
SPROUT_CONSTEXPR_OR_CONST int sprout::random::linear_feedback_shift_engine<UIntType, w, k, q, s>::word_size;
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
SPROUT_CONSTEXPR_OR_CONST int sprout::random::linear_feedback_shift_engine<UIntType, w, k, q, s>::exponent1;
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
SPROUT_CONSTEXPR_OR_CONST int sprout::random::linear_feedback_shift_engine<UIntType, w, k, q, s>::exponent2;
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
SPROUT_CONSTEXPR_OR_CONST int sprout::random::linear_feedback_shift_engine<UIntType, w, k, q, s>::step_size;
|
|
template<typename UIntType, int w, int k, int q, int s>
|
|
SPROUT_CONSTEXPR_OR_CONST UIntType sprout::random::linear_feedback_shift_engine<UIntType, w, k, q, s>::default_seed;
|
|
} // namespace random
|
|
|
|
using sprout::random::linear_feedback_shift_engine;
|
|
} // namespace sprout
|
|
|
|
#endif // #ifndef SPROUT_RANDOM_LINEAR_FEEDBACK_SHIFT_HPP
|