[Bug-gnubg] misevaluation on 0-ply

[Sven-Olav Norén]

Hi,
 
Hope you can read the position below. As you can see GNU makes a big misstep on 0-ply evaluation. GNU:s choice loses about 80% gammons instead of a normal gammon saving move that would lose about 40% gammon. GNU corrects itself on 1-ply and higher levels, so it might have no or small practical importance. However it bothers me as I often use 0-ply when doing rollouts. So I'm curious if anyone with inight in the neural nets might have some explanation or comment.
 
 
Kind regards
Sven-Olav Norén, Stockholm Sweden
 
2wIAAKuzqgIAAA:MIGpAAAAAAAA
 
The score (after 0 games) is: gnubg 0, snoren 0 (match to 5 points)
Match Information:
Date: 2008-11-10
Move number 3:  gnubg to play 32
 GNU Backgammon  Position ID: 2wIAAKuzqgIAAA
                 Match ID   : MIGpAAAAAAAA
 +12-11-10--9--8--7-------6--5--4--3--2--1-+     O: gnubg
 | O  O  O  O  O  O |   | O     O  O  O  O |     0 points
 |                  |   | O     O        O |     Rolled 32
 |                  |   |       O          |    
 |                  |   |                  |    
 |                  |   |                  |   
^|                  |BAR|                  |     5 point match (Cube: 1)
 |                  |   |                  | X 
 |                  |   |                  | X  
 |                  |   |                  | XX 
 |                  |   |          X  X  X | XX 
 |                  |   |       X  X  X  X | XX  0 points
 +13-14-15-16-17-18------19-20-21-22-23-24-+     X: snoren
Pip counts: O 88, X 16
 
Rolled 32:     1. Cubeful 0-ply    4/2 4/1                      Eq.:  -1,407
       0,000 0,000 0,000 - 1,000 0,433 0,000
     2. Cubeful 0-ply    9/6 8/6                      Eq.:  -1,432 ( -0,025)
       0,000 0,000 0,000 - 1,000 0,459 0,000
     3. Cubeful 0-ply    9/6 7/5                      Eq.:  -1,443 ( -0,036)
       0,000 0,000 0,000 - 1,000 0,471 0,000
     4. Cubeful 0-ply    12/10 9/6                    Eq.:  -1,446 ( -0,040)
       0,000 0,000 0,000 - 1,000 0,475 0,000
     5. Cubeful 0-ply    12/9 8/6                     Eq.:  -1,471 ( -0,065)
       0,000 0,000 0,000 - 1,000 0,501 0,000

Output generated Mon Nov 10 13:29:07 2008
by GNU Backgammon 0.90-mingw (Text Export version 1.91)
 

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