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https://github.com/bolero-MURAKAMI/Sprout.git
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108 lines
3.3 KiB
C++
108 lines
3.3 KiB
C++
#ifndef SPROUT_RANDOM_ADDITIVE_COMBINE_HPP
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#define SPROUT_RANDOM_ADDITIVE_COMBINE_HPP
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#include <cstdint>
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#include <ios>
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#include <istream>
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#include <sprout/config.hpp>
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#include <sprout/random/random_result.hpp>
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#include <sprout/random/linear_congruential.hpp>
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namespace sprout {
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namespace random {
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//
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// additive_combine_engine
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//
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template<typename MLCG1, typename MLCG2>
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class additive_combine_engine {
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public:
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typedef MLCG1 first_base;
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typedef MLCG2 second_base;
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typedef typename first_base::result_type result_type;
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private:
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struct private_constructor_tag {};
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private:
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first_base mlcg1_;
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second_base mlcg2_;
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private:
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SPROUT_CONSTEXPR additive_combine_engine(
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first_base const& mlcg1,
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second_base const& mlcg2,
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private_constructor_tag
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)
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: mlcg1_(mlcg1)
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, mlcg2_(mlcg2)
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{}
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template<typename Random1, typename Random2>
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SPROUT_CONSTEXPR sprout::random::random_result<additive_combine_engine> generate(Random1 const& rnd1, Random2 const& rnd2) const {
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return sprout::random::random_result<additive_combine_engine>(
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rnd2.result() < rnd1.result()
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? rnd1.result() - rnd2.result()
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: rnd1.result() - rnd2.result() + first_base::modulus - 1
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,
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additive_combine_engine(
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rnd1.engine(),
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rnd2.engine(),
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private_constructor_tag()
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)
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);
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}
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public:
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SPROUT_CONSTEXPR additive_combine_engine()
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: mlcg1_()
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, mlcg2_()
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{}
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SPROUT_CONSTEXPR explicit additive_combine_engine(result_type const& seed)
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: mlcg1_(seed)
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, mlcg2_(seed)
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{}
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SPROUT_CONSTEXPR additive_combine_engine(typename MLCG1::result_type seed1, typename MLCG2::result_type seed2)
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: mlcg1_(seed1)
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, mlcg2_(seed2)
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{}
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SPROUT_CONSTEXPR result_type min() const {
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return 1;
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}
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SPROUT_CONSTEXPR result_type max() const {
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return first_base::modulus - 1;
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}
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SPROUT_CONSTEXPR sprout::random::random_result<additive_combine_engine> operator()() const {
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return generate(mlcg1_(), mlcg2_());
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}
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friend SPROUT_CONSTEXPR bool operator==(additive_combine_engine const& lhs, additive_combine_engine const& rhs) {
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return lhs.mlcg1_ == rhs.mlcg1_ && lhs.mlcg2_ == rhs.mlcg2_;
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}
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friend SPROUT_CONSTEXPR bool operator!=(additive_combine_engine const& lhs, additive_combine_engine const& rhs) {
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return !(lhs == rhs);
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}
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template<typename Elem, typename Traits>
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friend std::basic_istream<Elem, Traits>& operator>>(
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std::basic_istream<Elem, Traits>& lhs,
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additive_combine_engine& rhs
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)
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{
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return lhs >> rhs.mlcg1_ >> std::ws >> rhs.mlcg2_;
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}
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template<typename Elem, typename Traits>
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friend std::basic_ostream<Elem, Traits>& operator<<(
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std::basic_ostream<Elem, Traits>& lhs,
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additive_combine_engine const& rhs
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)
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{
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return lhs << rhs.mlcg1_ << ' ' << rhs.mlcg2_;
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}
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};
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//
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// ecuyer1988
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//
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typedef additive_combine_engine<
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sprout::random::linear_congruential_engine<std::uint32_t, 40014, 0, 2147483563>,
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sprout::random::linear_congruential_engine<std::uint32_t, 40692, 0, 2147483399>
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> ecuyer1988;
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} // namespace random
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using sprout::random::ecuyer1988;
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} // namespace sprout
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#endif // #ifndef SPROUT_RANDOM_ADDITIVE_COMBINE_HPP
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