Tag: Search Reduction

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MadChess 2.0 Beta Build 074 (Tune Reductions And Pruning)

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I tuned parameters related to search reductions and move pruning.  The {3, 7} in the code below means reduce the 3rd quiet move one ply, and reduce the 7th quiet move two plies. This added 20 Elo to the playing strength of MadChess 2.0 Beta. MadChess 2.0 2262 : 1600 (+738,=325,-537), 56.3 % vs. : games ( +, =, -), (%) : Diff, SD, CFS (%) Glass 1.6 : 100 ( 16, 24, 60), 28.0 : -186, 10, 0.0 RomiChess P3L : 100 ( 18, 18, 64), 27.0 : -171, 12, 0.0 OliThink 5.3.2 : 100 ( 16, 24, 60),… Continue Reading

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MadChess 2.0 Beta Build 040 (History Heuristic + Late Move Reductions)

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I added a history heuristic and late move reductions to MadChess 2.0 Beta. When a move causes a beta cutoff, the move’s history value is incremented by the distance to the horizon squared. (Distance to the horizon squared is used to prevent moves deep in the search tree from having too much influence over move order.) A history value is saved for each combination of piece type and move destination square. Moves are ordered by their history values descending (after cached best move, capture victim, capture attacker, promoted piece, and killer moves). The search horizon is reduced for moves that… Continue Reading