/*
Stockfish, a UCI chess playing engine derived from Glaurung 2.1
Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
+ Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad
Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#ifndef MISC_H_INCLUDED
#define MISC_H_INCLUDED
+#include <cassert>
#include <ostream>
#include <string>
#include <vector>
/// This class is based on original code written and dedicated
/// to the public domain by Sebastiano Vigna (2014).
/// It has the following characteristics:
+///
/// - Outputs 64-bit numbers
/// - Passes Dieharder and SmallCrush test batteries
/// - Does not require warm-up, no zeroland to escape
/// - Internal state is a single 64-bit integer
/// - Period is 2^64 - 1
/// - Speed: 1.60 ns/call (Core i7 @3.40GHz)
+///
/// For further analysis see
/// <http://vigna.di.unimi.it/ftp/papers/xorshift.pdf>
class PRNG {
- uint64_t x;
+ uint64_t s;
uint64_t rand64() {
- x^=x>>12; x^=x<<25; x^=x>>27;
- return x * 2685821657736338717LL;
+
+ s ^= s >> 12, s ^= s << 25, s ^= s >> 27;
+ return s * 2685821657736338717LL;
}
public:
- PRNG(uint64_t seed) : x(seed) { assert(seed); }
+ PRNG(uint64_t seed) : s(seed) { assert(seed); }
template<typename T> T rand() { return T(rand64()); }
/// Special generator used to fast init magic numbers.
/// Output values only have 1/8th of their bits set on average.
- template<typename T> T sparse_rand() { return T(rand64() & rand64() & rand64()); }
+ template<typename T> T sparse_rand()
+ { return T(rand64() & rand64() & rand64()); }
};
#endif // #ifndef MISC_H_INCLUDED