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fc27d158c0
This fixes #3108 and removes some NNUE code that is currently not used. At the moment, do_null_move() copies the accumulator from the previous state into the new state, which is correct. It then clears the "computed_score" flag because the side to move has changed, and with the other side to move NNUE will return a completely different evaluation (normally with changed sign but also with different NNUE-internal tempo bonus). The problem is that do_null_move() clears the wrong flag. It clears the computed_score flag of the old state, not of the new state. It turns out that this almost never affects the search. For example, fixing it does not change the current bench (but it does change the previous bench). This is because the search code usually avoids calling evaluate() after a null move. This PR corrects do_null_move() by removing the computed_score flag altogether. The flag is not needed because nnue_evaluate() is never called twice on a position. This PR also removes some unnecessary {}s and inserts a few blank lines in the modified NNUE files in line with SF coding style. Resulf ot STC non-regression test: LLR: 2.95 (-2.94,2.94) {-1.25,0.25} Total: 26328 W: 3118 L: 3012 D: 20198 Ptnml(0-2): 126, 2208, 8397, 2300, 133 https://tests.stockfishchess.org/tests/view/5f553ccc2d02727c56b36db1 closes https://github.com/official-stockfish/Stockfish/pull/3109 bench: 4109324
38 lines
1.3 KiB
C++
38 lines
1.3 KiB
C++
/*
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Stockfish, a UCI chess playing engine derived from Glaurung 2.1
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Copyright (C) 2004-2020 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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// Class for difference calculation of NNUE evaluation function
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#ifndef NNUE_ACCUMULATOR_H_INCLUDED
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#define NNUE_ACCUMULATOR_H_INCLUDED
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#include "nnue_architecture.h"
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namespace Eval::NNUE {
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// Class that holds the result of affine transformation of input features
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struct alignas(kCacheLineSize) Accumulator {
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std::int16_t
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accumulation[2][kRefreshTriggers.size()][kTransformedFeatureDimensions];
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bool computed_accumulation;
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};
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} // namespace Eval::NNUE
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#endif // NNUE_ACCUMULATOR_H_INCLUDED
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