I added king safety evaluation to MadChess 2.0 Beta. Defects in king protection (missing pawn shield, semi-open files adjacent to king, squares near king attacked by enemy pieces) are counted, then used as an index into a non-linear piece coordination table.
It took me several attempts to calibrate the weights and the non-linear penalty, but eventually I found an improvement. This added 27 Elo to the playing strength of MadChess 2.0 Beta.
MadChess 2.0 1904 : 800 (+233,=127,-440), 37.1 % vs. : games ( +, =, -), (%) : Diff, SD, CFS (%) BikJump v2.01 : 100 ( 6, 18, 76), 15.0 : -190, 12, 0.0 Matheus-2.3 : 100 ( 17, 18, 65), 26.0 : -165, 12, 0.0 Monarch 1.7 : 100 ( 18, 15, 67), 25.5 : -142, 13, 0.0 BigLion 2.23w : 100 ( 29, 16, 55), 37.0 : -107, 12, 0.0 Faile 1.4 : 100 ( 33, 19, 48), 42.5 : -96, 10, 0.0 Sharper 0.17 : 100 ( 32, 18, 50), 41.0 : -87, 12, 0.0 Jabba13032012 : 100 ( 46, 8, 46), 50.0 : -28, 11, 0.5 Roce 0.0390 : 100 ( 52, 15, 33), 59.5 : +49, 11, 100.0
Feature | Category | Date | Rev1 | WAC2 | Elo Rating3 | Improvement |
---|---|---|---|---|---|---|
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 | – |
- Subversion source code revision
- Win At Chess position test, 3 seconds per position
- Bullet chess, 2 min / game + 1 sec / move