Dev Builds » 20180304-1555

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NCM plays each Stockfish dev build 20,000 times against Stockfish 14. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.


Host Duration Avg Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo

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ID Host Base NPS Games WLD Standard Elo Ptnml(0-2) Gamepair Elo CLI PGN


Commit ID 450f04969c5699fb9a4b39b883c2f37d122de290
Author Stefano Cardanobile
Date 2018-03-04 15:55:58 UTC
Using a S-curve for the optimism measure Add a logarithmic term in the optimism computation, increase the maximal optimism and lower the contempt offset. This increases the dynamics of the optimism aspects, giving a boost for balanced positions without skewing too much on unbalanced positions (but this version will enter panic mode faster than previous master when behind, trying to draw faster when slightly behind). This helps, since optimism is in general a good thing, for instance at LTC, but too high optimism rapidly contaminates play. passed STC: LLR: 2.96 (-2.94,2.94) [0.00,5.00] Total: 159343 W: 34489 L: 33588 D: 91266 passed LTC: LLR: 2.97 (-2.94,2.94) [0.00,5.00] Total: 47491 W: 7825 L: 7517 D: 32149 It must be mentioned that a version of the PR with contempt 0 did not pass STC [0,5]. The version in the patch, which uses default contempt 12, was found to be as strong as current master on different matches against SF7 and SF8, both at STC and LTC. One drawback maybe is that it raises the draw rate in self-play from 56% to 59%, giving a little bit less sensitivity for SF developpers to find evaluation improvements by selfplay tests in fishtest. Possible further work: • tune the values accurately, while keeping in mind the drawrate issue • check whether it is possible to remove linear and offset term • try to simplify the S-shape curve Bench: 5934644
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