Dev Builds » 20180209-1807

Use this dev build

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

Test Detail

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


Commit ID cb1324312d051269700b74cb59759a12530d0b7a
Author Stefano Cardanobile
Date 2018-02-09 18:07:19 UTC
Introduce dynamic contempt Make contempt dependent on the current score of the root position. The idea is that we now use a linear formula like the following to decide on the contempt to use during a search : contempt = x + y * eval where x is the base contempt set by the user in the "Contempt" UCI option, and y * eval is the dynamic part which adapts itself to the estimation of the evaluation of the root position returned by the search. In this patch, we use x = 18 centipawns by default, and the y * eval correction can go from -20 centipawns if the root eval is less than -2.0 pawns, up to +20 centipawns when the root eval is more than 2.0 pawns. To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if Stockfish is losing or winning, with an average value of 0.18 pawns by default. STC: LLR: 2.95 (-2.94,2.94) [0.00,5.00] Total: 110052 W: 24614 L: 23938 D: 61500 LTC: LLR: 2.97 (-2.94,2.94) [0.00,5.00] Total: 16470 W: 2896 L: 2705 D: 10869 A second match at LTC was organised against the current master: ELO: 1.45 +-2.9 (95%) LOS: 84.0% Total: 19369 W: 3350 L: 3269 D: 12750 Finally, we checked that there is no apparent problem with multithreading, despite the fact that some threads might have a slightly different contempt level that the main thread. Match of this version against master, both using 5 threads, time control 30+0.3: ELO: 2.18 +-3.2 (95%) LOS: 90.8% Total: 14840 W: 2502 L: 2409 D: 9929 Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc. Bench: 5207156
Copyright 2011–2024 Next Chess Move LLC