MadChess 2.0 Beta Build 052 (Unstoppable Pawns, Draws, Material Trades)

I added code to detect unstoppable passed pawns and drawn endgames, and code to evaluate material trades. The code that evaluates material trades implements the age old advice, “When ahead trade pieces. When behind trade pawns.” A greater bonus is giving for trading pawns, since in many endgames the side with a material advantage cannot win without promoting a pawn.

This added 39 Elo to the playing strength of MadChess 2.0 Beta.

MadChess 2.0                   2193 :    800 (+399,=168,-233),  60.4 %

vs.                                 :  games (   +,   =,   -),   (%) :   Diff,  SD, CFS (%)
Glass 1.6                           :     50 (   4,   7,  39),  15.0 :   -223,  27,    0.0
Sungorus 1.4                        :     50 (  18,   7,  25),  43.0 :   -117,  12,    0.0
ZCT 0.3.2450                        :     50 (  13,  12,  25),  38.0 :    -15,  14,   14.3
FireFly v2.6.0                      :     50 (  18,  19,  13),  55.0 :    -13,  15,   19.0
Jazz v444                           :     50 (  19,  15,  16),  53.0 :     +9,  14,   73.6
Beowulf 2.4                         :     50 (  21,  13,  16),  55.0 :    +31,  20,   93.9
Wing 2.0                            :     50 (  22,  11,  17),  55.0 :    +71,  15,  100.0
Brainless 1.0                       :     50 (  26,  11,  13),  63.0 :    +82,  19,  100.0
BikJump v2.01                       :     50 (  22,  10,  18),  54.0 :    +93,  13,  100.0
Matheus-2.3                         :     50 (  21,  17,  12),  59.0 :   +115,  13,  100.0
Monarch 1.7                         :     50 (  28,  11,  11),  67.0 :   +142,  15,  100.0
BigLion 2.23w                       :     50 (  32,  12,   6),  76.0 :   +170,  13,  100.0
Sharper 0.17                        :     50 (  37,   5,   8),  79.0 :   +184,  13,  100.0
Faile 1.4                           :     50 (  36,  12,   2),  84.0 :   +213,  12,  100.0
Jabba13032012                       :     50 (  41,   1,   8),  83.0 :   +242,  13,  100.0
Roce 0.0390                         :     50 (  41,   5,   4),  87.0 :   +311,  13,  100.0
Feature Category Date Rev1 WAC2 Elo Rating3 Improvement
Unstoppable Pawns
Draws, Material Trades
Evaluation 2015 Jan 31 52 270 2193 +39
Late Move Pruning Search 2015 Jan 10 44 273 2154 +39
History Heuristic
Late Move Reductions
Search 2015 Jan 04 40 275 2115 +50
Killer Moves Search 2015 Jan 03 38 275 2065 +61
Futility Pruning Search 2014 Dec 29 37 256 2004 +54
Null Move
Quiescence Recaptures
Search 2014 Dec 28 34 242 1950 +46
King Safety Evaluation 2014 Dec 24 32 225 1904 +27
Piece Mobility Evaluation 2014 Dec 16 29 225 1877 +64
Draw By Repetition Bug Evaluation 2014 Dec 10 27 225 1813 +47
Passed Pawns Evaluation 2014 Dec 09 26 225 1766 +72
Time Management Search 2014 Dec 08 25 231 1694 +24
Delay Move Generation
Aspiration Window Bug
Search 2014 Dec 02 23 231 1670 +44
MVV / LVA Move Order
Draw By Insufficient Material
Move List Overflow Bug
Search 2014 Dec 01 22 235 1626 +30
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. Subversion source code revision
  2. Win At Chess position test, 3 seconds per position
  3. Bullet chess, 2 min / game + 1 sec / move
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