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Sprout/sprout/random/inversive_congruential.hpp
2014-11-28 16:19:07 +09:00

185 lines
7.8 KiB
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/*=============================================================================
Copyright (c) 2011-2014 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_INVERSIVE_CONGRUENTIAL_HPP
#define SPROUT_RANDOM_INVERSIVE_CONGRUENTIAL_HPP
#include <cstdint>
#include <istream>
#include <ostream>
#include <type_traits>
#include <sprout/config.hpp>
#include <sprout/limits.hpp>
#include <sprout/random/detail/const_mod.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>
#include <sprout/math/greater_equal.hpp>
#include <sprout/assert.hpp>
namespace sprout {
namespace random {
//
// inversive_congruential_engine
//
template<typename IntType, IntType a, IntType b, IntType p>
class inversive_congruential_engine {
public:
typedef IntType result_type;
private:
struct private_construct_t {};
public:
SPROUT_STATIC_CONSTEXPR result_type multiplier = a;
SPROUT_STATIC_CONSTEXPR result_type increment = b;
SPROUT_STATIC_CONSTEXPR result_type modulus = p;
SPROUT_STATIC_CONSTEXPR result_type default_seed = 1;
public:
static SPROUT_CONSTEXPR result_type static_min() SPROUT_NOEXCEPT {
return increment == 0 ? 1 : 0;
}
static SPROUT_CONSTEXPR result_type static_max() SPROUT_NOEXCEPT {
return modulus - 1;
}
static SPROUT_CONSTEXPR result_type init_seed_3(result_type x0) {
return SPROUT_ASSERT(sprout::math::greater_equal(x0, static_min())), SPROUT_ASSERT(x0 <= static_max()), x0;
}
static SPROUT_CONSTEXPR result_type init_seed_2(result_type x0) {
return init_seed_3(increment == 0 && x0 == 0 ? 1 : x0);
}
static SPROUT_CONSTEXPR result_type init_seed_1(result_type x0) {
return init_seed_2(x0 <= 0 && x0 != 0 ? x0 + modulus : x0);
}
static SPROUT_CONSTEXPR result_type init_seed(result_type x0 = default_seed) {
return init_seed_1(modulus == 0 ? x0 : x0 % modulus);
}
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, modulus>(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, modulus>(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, modulus>(first, last));
}
private:
result_type x_;
private:
SPROUT_CONSTEXPR inversive_congruential_engine(result_type x, private_construct_t)
: x_(x)
{}
SPROUT_CONSTEXPR sprout::random::random_result<inversive_congruential_engine>
generate(result_type result) const {
return sprout::random::random_result<inversive_congruential_engine>(
result,
inversive_congruential_engine(result, private_construct_t())
);
}
public:
SPROUT_CONSTEXPR inversive_congruential_engine()
: x_(init_seed(default_seed))
{}
inversive_congruential_engine(inversive_congruential_engine const&) = default;
explicit SPROUT_CONSTEXPR inversive_congruential_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 inversive_congruential_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 inversive_congruential_engine(Sseq const& seq)
: x_(init_seed(seq))
{}
template<typename InputIterator>
SPROUT_CONSTEXPR inversive_congruential_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()() {
typedef sprout::random::detail::const_mod<result_type, p> do_mod;
x_ = do_mod::mult_add(a, do_mod::invert(x_), b);
return x_;
}
SPROUT_CONSTEXPR sprout::random::random_result<inversive_congruential_engine> const operator()() const {
typedef sprout::random::detail::const_mod<result_type, p> do_mod;
return generate(do_mod::mult_add(a, do_mod::invert(x_), b));
}
friend SPROUT_CONSTEXPR bool operator==(inversive_congruential_engine const& lhs, inversive_congruential_engine const& rhs) SPROUT_NOEXCEPT {
return lhs.x_ == rhs.x_;
}
friend SPROUT_CONSTEXPR bool operator!=(inversive_congruential_engine const& lhs, inversive_congruential_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,
inversive_congruential_engine& rhs
)
{
result_type x;
if (lhs >> x) {
if (sprout::math::greater_equal(x, static_min()) && x <= static_max()) {
rhs.x_ = x;
} else {
lhs.setstate(std::ios_base::failbit);
}
}
return lhs;
}
template<typename Elem, typename Traits>
friend SPROUT_NON_CONSTEXPR std::basic_ostream<Elem, Traits>& operator<<(
std::basic_ostream<Elem, Traits>& lhs,
inversive_congruential_engine const& rhs
)
{
return lhs << rhs.x_;
}
};
template<typename IntType, IntType a, IntType b, IntType p>
SPROUT_CONSTEXPR_OR_CONST IntType sprout::random::inversive_congruential_engine<IntType, a, b, p>::multiplier;
template<typename IntType, IntType a, IntType b, IntType p>
SPROUT_CONSTEXPR_OR_CONST IntType sprout::random::inversive_congruential_engine<IntType, a, b, p>::increment;
template<typename IntType, IntType a, IntType b, IntType p>
SPROUT_CONSTEXPR_OR_CONST IntType sprout::random::inversive_congruential_engine<IntType, a, b, p>::modulus;
template<typename IntType, IntType a, IntType b, IntType p>
SPROUT_CONSTEXPR_OR_CONST IntType sprout::random::inversive_congruential_engine<IntType, a, b, p>::default_seed;
//
// hellekalek1995
//
typedef sprout::random::inversive_congruential_engine<std::uint_fast32_t, 9102, 2147483647 - 36884165, 2147483647> hellekalek1995;
} // namespace random
using sprout::random::inversive_congruential_engine;
using sprout::random::hellekalek1995;
} // namespace sprout
#endif // #ifndef SPROUT_RANDOM_INVERSIVE_CONGRUENTIAL_HPP