MadChess 2.0 Beta Build 021 (Tapered Evaluation)

I added tapered evaluation to MadChess 2.0 Beta. The evaluation assigns a material score, a middlegame piece location score, and an endgame piece location score. Then calculates the game phase and returns a weighted average of the middlegame and endgame scores.

By separating piece location scores into middlegame and endgame phases, I can encourage MadChess to hold its queen back during the middlegame, and bring its king to the center during the endgame, for example.

This added 107 ELO to the playing strength of MadChess 2.0 Beta.

MadChess 2.0                   1596 :    800 (+42,=72,-686),   9.8 %

vs.                                 :  games (  +,  =,   -),   (%) :   Diff,  SD, CFS (%)
BikJump v2.01                       :    100 (  0,  2,  98),   1.0 :   -490,  18,    0.0
Matheus-2.3                         :    100 (  3, 10,  87),   8.0 :   -467,  17,    0.0
Monarch 1.7                         :    100 (  2,  2,  96),   3.0 :   -446,  18,    0.0
BigLion 2.23w                       :    100 (  5, 11,  84),  10.5 :   -413,  17,    0.0
Faile 1.4                           :    100 (  7, 10,  83),  12.0 :   -404,  16,    0.0
Sharper 0.17                        :    100 (  4,  9,  87),   8.5 :   -396,  17,    0.0
Jabba13032012                       :    100 (  7, 12,  81),  13.0 :   -337,  17,    0.0
Roce 0.0390                         :    100 ( 14, 16,  70),  22.0 :   -258,  16,    0.0
Feature Category Date Build Number WAC1 ELO Rating2 Improvement
Tapered Evaluation
MG and EG Piece Location
Evaluation 2014 Nov 29 21 234 1596 +107
Alpha / Beta Negamax
Aspiration Windows
Quiescence, Hash
Material, Piece Squares
Baseline 2014 Nov 25 20 236 1489
  1. Win At Chess position test, 3 seconds per position
  2. Bullet chess, 2 min / game + 1 sec / move
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