MadChess 2.0 Beta Build 127 (Limit Strength)

I have added parameters to limit the playing strength of MadChess 2.0 Beta. The simplest way to limit the playing strength of MadChess 2.0 Beta is to set the LimitStrength and Elo parameters. The engine will automatically configure material scores and positional knowledge. In addition, the engine will configure search speed (Nodes Per Second), move error, blunder error, and blunder percent based on the Elo value. Continue Reading

MadChess 2.0 Beta Build 123 (Rook And Queen On 7th Rank)

I added rook and queen on 7th rank evaluation to MadChess 2.0 Beta. The code awards a bonus for a rook or queen on the 7th rank if the enemy king is on the 8th rank (its 1st rank). Also, I removed late move pruning. (When I implemented late move pruning in build 44 it added 39 ELO to the playing strength of MadChess 2.0 Beta.) I replaced it with more aggressive null and late move reductions, and more aggressive futility pruning, but found it decreased the playing strength. Next, I restored late move pruning and left in the aggressive… Continue Reading

MadChess 2.0 Beta Build 083 (Knight Outposts)

I added knight outpost evaluation to MadChess 2.0 Beta. Knights on the 5th rank or beyond are awarded a bonus if they cannot be attacked by enemy pawns and are supported by their own pawn. This added 25 ELO to the playing strength of MadChess 2.0 Beta. MadChess 2.0 2287 : 1600 (+785,=327,-488), 59.3 % vs. : games ( +, =, -), (%) : Diff, SD, CFS (%) Glass 1.6 : 100 ( 14, 15, 71), 21.5 : -187, 10, 0.0 RomiChess P3L : 100 ( 18, 28, 54), 32.0 : -145, 14, 0.0 OliThink 5.3.2 : 100 ( 21,… Continue Reading

MadChess 2.0 Beta Build 074 (Tune Reductions And Pruning)

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

MadChess 2.0 Beta Build 069 (Bishop Pair)

I added bishop pair evaluation to MadChess 2.0 Beta. The code awards a bonus for possessing two or more bishops, calibrated by game phase. This added 18 ELO to the playing strength of MadChess 2.0 Beta. MadChess 2.0 2242 : 1280 (+561,=259,-460), 53.9 % vs. : games ( +, =, -), (%) : Diff, SD, CFS (%) Glass 1.6 : 80 ( 12, 12, 56), 22.5 : -219, 16, 0.0 RomiChess P3L : 80 ( 8, 12, 60), 17.5 : -215, 18, 0.0 OliThink 5.3.2 : 80 ( 7, 10, 63), 15.0 : -202, 18, 0.0 Myrddin 0.87 : 80 (… Continue Reading