Dev Builds » 20181101-1500

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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 3f1eb85a1ceb1b408f8f51cb82064b69e095399d
Author Joost VandeVondele
Date 2018-11-01 15:00:56 UTC
Fix issues from using adjustedDepth too broadly The recently committed Fail-High patch (081af9080542a0d076a5482da37103a96ee15f64) had a number of changes beyond adjusting the depth of search on fail high, with some undesirable side effects. 1) Decreasing depth on PV output, confusing GUIs and players alike as described in issue #1787. The depth printed is anyway a convention, let's consider adjustedDepth an implementation detail, and continue to print rootDepth. Depth, nodes, time and move quality all increase as we compute more. (fixing this output has no effect on play). 2) Fixes go depth output (now based on rootDepth again, no effect on play), also reported in issue #1787 3) The depth lastBestDepth is used to compute how long a move is stable, a new move found during fail-high is incorrectly considered stable if based on adjustedDepth instead of rootDepth (this changes time management). Reverting this passed STC and LTC: STC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 82982 W: 17810 L: 17808 D: 47364 LTC LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 109083 W: 17602 L: 17619 D: 73862 4) In the thread voting scheme, the rank of the fail-high thread is now artificially low, incorrectly since the quality of the move is much better than what adjustedDepth suggests (e.g. if it takes 10 iterations to find VALUE_KNOWN_WIN, it has very low depth). Further evidence comes from a test that showed that the move of highest depth is not better than that of the last PV (which is potentially of much lower adjustedDepth). I.e. this test failed SPRT[0, 5]: LLR: -2.95 (-2.94,2.94) [0.00,5.00] Total: 10609 W: 2266 L: 2345 D: 5998 In a running 5+0.05 th 8 test (more than 10000 games) a positive Elo estimate is shown (strong enough for a [-3,1], possibly not [0,4]): LLR: -0.13 (-2.94,2.94) [0.00,4.00] Total: 13644 W: 2573 L: 2532 D: 8539 Elo 1.04 [-2.52,4.61] / LOS 71% Thus, restore old behavior as a bugfix, keeping the core of the fail-high patch idea as resolving scheme. This is non-functional for bench, but changes searches via time management and in the threaded case. Bench: 3556672
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