Dev Builds » 20191007-2030

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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 0150da5c2bd4661996b05dec4a1eca473515e9d7
Author Alayan
Date 2019-10-07 20:30:04 UTC
Adjust aspiration window with eval This patch changes the base aspiration window size depending on the absolute value of the previous iteration score, increasing it away from zero. This stems from the observation that the further away from zero, the more likely the evaluation is to change significantly with more depth. Conversely, a tighter aspiration window is more efficient when close to zero. A beneficial side-effect is that analysis of won positions without a quick mate is less prone to waste nodes in repeated fail-high that change the eval by tiny steps. STC: LLR: 2.96 (-2.94,2.94) [0.50,4.50] Total: 60102 W: 13327 L: 12868 D: 33907 LTC: LLR: 2.95 (-2.94,2.94) [0.00,3.50] Total: 155553 W: 25745 L: 25141 D: 104667 Future work : the values used in this patch were only a reasonable guess. Further testing should unveil more optimal values. However, the aspiration window is rather tight with a minimum of 21 internal units, so discrete integers put a practical limitation to such tweaking. More exotic experiments around the aspiration window parameters could also be tried, but efficient conditions to adjust the base aspiration window size or allow it to not be centered on the current evaluation are not obvious. The aspiration window increases after a fail-high or a fail-low is another avenue to explore for potential enhancements. Bench: 4043748
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