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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.


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Commit ID ad8b78ad5281138cfe188dedcf76ec8ef622531f
Author Sergei Ivanov
Date 2019-05-09 13:39:57 UTC
Fix cycle detection in presence of repetitions In master search() may incorrectly return a draw score in the following corner case: there was a 2-fold repetition during the game, and the current position can be reached by a move from a repeated one. This case is treated as an upcoming 3-fold repetition, which it is not. Here is a testcase demonstrating the issue (note that the moves after FEN are required). The input: position fen 8/8/8/8/8/8/p7/2k4K b - - 0 1 moves c1b1 h1g1 b1c1 g1h1 c1b1 h1g1 b1a1 g1h1 go movetime 1000 produces the output: [...] info depth 127 seldepth 2 multipv 1 score cp 0 [...] bestmove a1b1 saying that the game will be drawn by repetion. However the other possible move for black, Kb2, avoids repetitions and wins. The patch fixes this behavior. In particular it finds mate in 10 in the above position. STC: LLR: 2.95 (-2.94,2.94) [-3.00,1.00] Total: 10604 W: 2390 L: 2247 D: 5967 LTC: LLR: 2.96 (-2.94,2.94) [-3.00,1.00] Total: 19620 W: 3308 L: 3185 D: 13127 Bench is not changed since it does not test positions with history of moves. Bench: 3184182
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