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https://github.com/opelly27/Stockfish.git
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Stéphane Nicolet
b25d68f6ee
This patch implements the pure materialistic evaluation called simple_eval() to gain a speed-up during Stockfish search. We use the so-called lazy evaluation trick: replace the accurate but slow NNUE network evaluation by the super-fast simple_eval() if the position seems to be already won (high material advantage). To guard against some of the most obvious blunders introduced by this idea, this patch uses the following features which will raise the lazy evaluation threshold in some situations: - avoid lazy evals on shuffling branches in the search tree - avoid lazy evals if the position at root already has a material imbalance - avoid lazy evals if the search value at root is already winning/losing. Moreover, we add a small random noise to the simple_eval() term. This idea (stochastic mobility in the minimax tree) was worth about 200 Elo in the pure simple_eval() player on Lichess. Overall, the current implementation in this patch evaluates about 2% of the leaves in the search tree lazily. -------------------------------------------- STC: LLR: 2.94 (-2.94,2.94) <0.00,2.00> Total: 60352 W: 15585 L: 15234 D: 29533 Ptnml(0-2): 216, 6906, 15578, 7263, 213 https://tests.stockfishchess.org/tests/view/64f1d9bcbd9967ffae366209 LTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 35106 W: 8990 L: 8678 D: 17438 Ptnml(0-2): 14, 3668, 9887, 3960, 24 https://tests.stockfishchess.org/tests/view/64f25204f5b0c54e3f04c0e7 verification run at VLTC: LLR: 2.94 (-2.94,2.94) <0.50,2.50> Total: 74362 W: 19088 L: 18716 D: 36558 Ptnml(0-2): 6, 7226, 22348, 7592, 9 https://tests.stockfishchess.org/tests/view/64f2ecdbf5b0c54e3f04d3ae All three tests above were run with adjudication off, we also verified that there was no regression on matetracker (thanks Disservin!). ---------------------------------------------- closes https://github.com/official-stockfish/Stockfish/pull/4771 Bench: 1393714
57 lines
1.5 KiB
C++
57 lines
1.5 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file)
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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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*/
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#ifndef EVALUATE_H_INCLUDED
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#define EVALUATE_H_INCLUDED
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#include <string>
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#include "types.h"
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namespace Stockfish {
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class Position;
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enum Value : int;
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namespace Eval {
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std::string trace(Position& pos);
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Value simple_eval(const Position& pos, Color c);
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Value evaluate(const Position& pos);
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extern std::string currentEvalFileName;
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// The default net name MUST follow the format nn-[SHA256 first 12 digits].nnue
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// for the build process (profile-build and fishtest) to work. Do not change the
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// name of the macro, as it is used in the Makefile.
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#define EvalFileDefaultName "nn-c38c3d8d3920.nnue"
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namespace NNUE {
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void init();
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void verify();
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} // namespace NNUE
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} // namespace Eval
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} // namespace Stockfish
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#endif // #ifndef EVALUATE_H_INCLUDED
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