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89 lines (73 loc) · 2.75 KB
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/*
This file is part of Leela Zero.
Copyright (C) 2017-2019 Gian-Carlo Pascutto and contributors
Leela Zero is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Leela Zero is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Leela Zero. If not, see <http://www.gnu.org/licenses/>.
Additional permission under GNU GPL version 3 section 7
If you modify this Program, or any covered work, by linking or
combining it with NVIDIA Corporation's libraries from the
NVIDIA CUDA Toolkit and/or the NVIDIA CUDA Deep Neural
Network library and/or the NVIDIA TensorRT inference library
(or a modified version of those libraries), containing parts covered
by the terms of the respective license agreement, the licensors of
this Program grant you additional permission to convey the resulting
work.
*/
#ifndef RANDOM_H_INCLUDED
#define RANDOM_H_INCLUDED
#include "config.h"
#include <cstdint>
#include <limits>
/*
Random number generator xoroshiro128+
*/
class Random {
public:
Random() = delete;
Random(std::uint64_t seed = 0);
void seedrandom(std::uint64_t s);
// Random numbers from [0, max - 1]
template<int MAX>
std::uint32_t randfix() {
static_assert(0 < MAX &&
MAX < std::numeric_limits<std::uint32_t>::max(),
"randfix out of range");
// Last bit isn't random, so don't use it in isolation. We specialize
// this case.
static_assert(MAX != 2, "don't isolate the LSB with xoroshiro128+");
return gen() % MAX;
}
std::uint64_t randuint64();
// Random number from [0, max - 1]
std::uint64_t randuint64(const std::uint64_t max);
// return the thread local RNG
static Random& get_Rng();
// UniformRandomBitGenerator interface
using result_type = std::uint64_t;
constexpr static result_type min() {
return std::numeric_limits<result_type>::min();
}
constexpr static result_type max() {
return std::numeric_limits<result_type>::max();
}
result_type operator()() {
return gen();
}
private:
std::uint64_t gen();
std::uint64_t m_s[2];
};
// Specialization for last bit: use sign test
template<>
inline std::uint32_t Random::randfix<2>() {
return (gen() > (std::numeric_limits<std::uint64_t>::max() / 2));
}
#endif