[Bug-gnubg] Analysis changing the game record and producing garbage

[Neil Robins]

I have analysed several matches at 4-ply using the 20091002 Windows build. I am finding the move made in the game record often being changed from that actually played in the match to what GNU thought best - which obviosly then renders the rest of the game meaningless garbage full of illegal moves.

 

Example:

 

 GNU Backgammon  Position ID: sHPkASjg6+ABJA
                 Match ID   : MAH6ACAACAAA
 +12-11-10--9--8--7-------6--5--4--3--2--1-+     O: Opp
 | X           O  O |   | O           X  X |     2 points
 | X           O    |   | O                |     Rolled 46
 | X           O    |   | O                |    
 | X                |   | O                |    
 |                  |   | O                |   
^|                  |BAR|                  |     7 point match (Cube: 1)
 |                  |   |                  |   
 | O                |   |                  |    
 | O           X    |   | X                |    
 | O           X    |   | X  X             |    
 | O  X        X    |   | X  X     O     O |     1 point
 +13-14-15-16-17-18------19-20-21-22-23-24-+     X: You

 

 1. Cubeful 4-ply    24/18 22/18                  Eq.:  -0.209
       0.467 0.094 0.002 - 0.533 0.127 0.004
        4-ply cubeful prune
    2. Cubeful 4-ply    8/2* 6/2                     Eq.:  -0.327 ( -0.118)
       0.433 0.146 0.007 - 0.567 0.165 0.008
        4-ply cubeful prune

My opponent moved 8/2* 6/2 which is correctly highlighted in red. The problem is that GNU puts its preferred 24/18 22/18 into the game record in place of 8/2* 6/2 - thus rendering all further analysis of that game meaningless.

This nonsense seems to have affected almost all the games I have analysed.