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Chess engine: Stockfish 22020917 NNUE (Windows and Linux)



Stockfish - UCI chess engine, compiled by Michael Chaly
Rating CEDR=3577 (1 place)

Timestamp: 1644423420
Big search tuning

Most credits for this patch should go to @candirufish.
Based on his big search tuning (1M games at 20+0.1s)


with some hand polishing on top of it, which includes :
a) correcting trend sigmoid - for some reason original tuning resulted in it being negative. This heuristic was proven to be worth some elo for years so reversing it sign is probably some random artefact;
b) remove changes to continuation history based pruning - this heuristic historically was really good at providing green STCs and then failing at LTC miserably if we tried to make it more strict, original tuning was done at short time control and thus it became more strict - which doesn't scale to longer time controls;
c) remove changes to improvement - not really indended :).

passed STC
https://tests.stockfishchess.org/tests/view/6203526e88ae2c84271c2ee2
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 16840 W: 4604 L: 4363 D: 7873 Elo +4.97
Ptnml(0-2): 82, 1780, 4449, 2033, 76

passed LTC
https://tests.stockfishchess.org/tests/view/620376e888ae2c84271c35d4
LLR: 2.96 (-2.94,2.94) <0.50,3.00>
Total: 17232 W: 4771 L: 4542 D: 7919 Elo +4.62
Ptnml(0-2): 14, 1655, 5048, 1886, 13
bench 5030992

Stockfish 22020917 NNUE download

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