Dev Builds » 20191005-2257

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NCM plays each Stockfish dev build 20,000 times against Stockfish 15. This yields an approximate Elo difference and establishes confidence in the strength of the dev builds.

Summary

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

Test Detail

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

Commit

Commit ID ca7d4e9ac7b5ca74be8aa807fbdf139b2a0860ab
Author Brian Sheppard
Date 2019-10-05 22:57:00 UTC
Eliminate ONE_PLY Simplification that eliminates ONE_PLY, based on a suggestion in the forum that support for fractional plies has never been used, and @mcostalba's openness to the idea of eliminating it. We lose a little bit of type safety by making Depth an integer, but in return we simplify the code in search.cpp quite significantly. No functional change ------------------------------------------ The argument favoring eliminating ONE_PLY: * The term “ONE_PLY” comes up in a lot of forum posts (474 to date) https://groups.google.com/forum/?fromgroups=#!searchin/fishcooking/ONE_PLY%7Csort:relevance * There is occasionally a commit that breaks invariance of the code with respect to ONE_PLY https://groups.google.com/forum/?fromgroups=#!searchin/fishcooking/ONE_PLY%7Csort:date/fishcooking/ZIPdYj6k0fk/KdNGcPWeBgAJ * To prevent such commits, there is a Travis CI hack that doubles ONE_PLY and rechecks bench * Sustaining ONE_PLY has, alas, not resulted in any improvements to the engine, despite many individuals testing many experiments over 5 years. The strongest argument in favor of preserving ONE_PLY comes from @locutus: “If we use par example ONE_PLY=256 the parameter space is increases by the factor 256. So it seems very unlikely that the optimal setting is in the subspace of ONE_PLY=1.” There is a strong theoretical impediment to fractional depth systems: the transposition table uses depth to determine when a stored result is good enough to supply an answer for a current search. If you have fractional depths, then different pathways to the position can be at fractionally different depths. In the end, there are three separate times when a proposal to remove ONE_PLY was defeated by the suggestion to “give it a few more months.” So… it seems like time to remove this distraction from the community. See the pull request here: https://github.com/official-stockfish/Stockfish/pull/2289
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