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https://github.com/sockspls/badfish
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4cd53b68d0
Search at fixed depth with one thread must be reproducible so remove randomess from time(). Also better license description. Signed-off-by: Marco Costalba <mcostalba@gmail.com>
84 lines
2.3 KiB
C++
84 lines
2.3 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
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Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
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Stockfish is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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Stockfish is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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This file is based on original code by Heinz van Saanen and is
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available under the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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** A small "keep it simple and stupid" RNG with some fancy merits:
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**
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** Quite platform independent
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** Passes ALL dieharder tests! Here *nix sys-rand() e.g. fails miserably:-)
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** ~12 times faster than my *nix sys-rand()
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** ~4 times faster than SSE2-version of Mersenne twister
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** Average cycle length: ~2^126
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** 64 bit seed
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** Return doubles with a full 53 bit mantissa
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** Thread safe
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**
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** (c) Heinz van Saanen
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*/
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#if !defined(RKISS_H_INCLUDED)
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#define RKISS_H_INCLUDED
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////
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//// Includes
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////
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#include "types.h"
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////
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//// Types
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////
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class RKISS {
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// Keep variables always together
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struct S { uint64_t a, b, c, d; } s;
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// Return 64 bit unsigned integer in between [0,2^64-1]
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uint64_t rand64() {
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const uint64_t
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e = s.a - ((s.b << 7) | (s.b >> 57));
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s.a = s.b ^ ((s.c << 13) | (s.c >> 51));
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s.b = s.c + ((s.d << 37) | (s.d >> 27));
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s.c = s.d + e;
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return s.d = e + s.a;
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}
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// Init seed and scramble a few rounds
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void raninit() {
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s.a = 0xf1ea5eed;
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s.b = s.c = s.d = 0xd4e12c77;
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for (uint64_t i = 0; i < 73; i++)
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rand64();
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}
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public:
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RKISS() { raninit(); }
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template<typename T> T rand() { return T(rand64()); }
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};
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#endif // !defined(RKISS_H_INCLUDED)
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