MadChess 2.0 Beta Build 023 (Delay Move Generation)

I added code to delay move generation if a cached position specifies a best move. The best move is played first. If it causes a beta cutoff, the expense of generating moves is avoided. If not, moves are generated and searched, skipping the best move, which has already been searched.

Also, I corrected a bug that caused all searches to use an infinite aspiration window.  The corrected code will search the first ply using an infinite aspiration window, then search subsequent plies with a narrow window around the first ply’s score.  If the score of subsequent searches lies on an aspiration boundary, the window gradually is widened from 50 to 200 to 500 to infinite centipawns.

This added 44 ELO to the playing strength of MadChess 2.0 Beta

MadChess 2.0                   1670 :    800 (+64,=100,-636),  14.3 %

vs.                                 :  games (  +,   =,   -),   (%) :   Diff,  SD, CFS (%)
BikJump v2.01                       :    100 (  1,   7,  92),   4.5 :   -413,  17,    0.0
Matheus-2.3                         :    100 (  6,  13,  81),  12.5 :   -389,  16,    0.0
Monarch 1.7                         :    100 (  3,  10,  87),   8.0 :   -368,  17,    0.0
BigLion 2.23w                       :    100 ( 11,  11,  78),  16.5 :   -335,  14,    0.0
Faile 1.4                           :    100 (  3,  15,  82),  10.5 :   -330,  14,    0.0
Sharper 0.17                        :    100 ( 12,   9,  79),  16.5 :   -318,  16,    0.0
Jabba13032012                       :    100 ( 15,  12,  73),  21.0 :   -259,  15,    0.0
Roce 0.0390                         :    100 ( 13,  23,  64),  24.5 :   -184,  14,    0.0
Feature Category Date Build Number WAC1 ELO Rating2 Improvement
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. Win At Chess position test, 3 seconds per position
  2. Bullet chess, 2 min / game + 1 sec / move
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