bug-gnubg
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Bug-gnubg] Possible evaluation bug


From: Øystein Schønning-Johansen
Subject: Re: [Bug-gnubg] Possible evaluation bug
Date: Sat, 17 Feb 2018 11:44:29 +0100

Really strange. However it is a heisenbug (of course). I cannot recreate the bug on my system. (GNU Backgammon 1.06.000  Dec 13 2017, Arch Linux)

Here is how the same thing looks at my system:

 GNU Backgammon  Position ID: PgAAALYLBDMMAA                                   
                 Match ID   : cImmADAAAAAE
 +13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
 | X              X |   |    X        O  X | OO  3 points
 |                X |   |    X        O  X | OO  
 |                  |   |             O    | OO  
 |                  |   |             O    | OO  
 |                  |   |             O    | OO 
v|                  |BAR|                  |     5 point match (Cube: 1)
 |                  |   |                  |    
 |                  |   |                  |     
 |                  |   | X                |     
 |                  |   | X  X  X          |     Rolled 51
 |                X |   | X  X  X          |     0 points
 +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: oystein


Cube analysis
2-ply cubeless equity -2.2349 (Money: -2.0391)
  0.0860 0.0000 0.0000 - 0.9140 0.7715 0.4396
Cubeful equities:
1. No double           -2.0550
2. Double, pass        +1.0000  (+3.0550)
3. Double, take        -2.4258  (-0.3708)
Proper cube action: No double, take (10.8%)

Rolled 51 (-0.066):
*    1. Cubeful 2-ply    24/19 18/17                  Eq.: -2.0615
       0.0892 0.0000 0.0000 - 0.9108 0.7435 0.6447
        2-ply cubeful prune [world class]
     2. Cubeful 2-ply    13/7                         Eq.: -2.1614 (-0.0999)
       0.0707 0.0000 0.0000 - 0.9293 0.7800 0.6404
        2-ply cubeful prune [world class]
     3. Cubeful 2-ply    13/8 6/5                     Eq.: -2.1766 (-0.1151)
       0.0701 0.0000 0.0000 - 0.9299 0.7866 0.6634
        2-ply cubeful prune [world class]
     4. Cubeful 2-ply    18/13 6/5                    Eq.: -2.1963 (-0.1348)
       0.0603 0.0000 0.0000 - 0.9397 0.7831 0.6918
        2-ply cubeful prune [world class]
     5. Cubeful 2-ply    18/17 18/13                  Eq.: -2.2086 (-0.1470)
       0.0567 0.0000 0.0000 - 0.9433 0.7815 0.7003
        2-ply cubeful prune [world class]
     6. Cubeful 2-ply    18/12                        Eq.: -2.2291 (-0.1676)
       0.0544 0.0000 0.0000 - 0.9456 0.7887 0.6961
        2-ply cubeful prune [world class]
     7. Cubeful 2-ply    18/17 13/8                   Eq.: -2.2481 (-0.1866)
       0.0524 0.0000 0.0000 - 0.9476 0.7953 0.6954
        2-ply cubeful prune [world class]
     8. Cubeful 2-ply    18/17 7/2                    Eq.: -2.2952 (-0.2337)
       0.0476 0.0000 0.0000 - 0.9524 0.8135 0.7098
        2-ply cubeful prune [world class]
     9. Cubeful 0-ply    24/19 6/5                    Eq.: -2.1277 (-0.0661)
       0.0653 0.0000 0.0000 - 0.9347 0.7599 0.4187
        0-ply cubeful prune [expert]
    10. Cubeful 0-ply    18/13 7/6                    Eq.: -2.1289 (-0.0674)
       0.0648 0.0000 0.0000 - 0.9352 0.7593 0.5707
        0-ply cubeful prune [expert]

I'm on this system:
address@hidden ~]$ gnubg -t < terjebug.txt
GNU Backgammon 1.06.000  Dec 13 2017

Can you supply which OS, version/build of GNU Backgammon (well that looks like you got "GNU Backgammon 1.05.000  Nov 27 2016"). Can you also state which match equity table you are using?

I have a theory that it get's the wrong answer because it calculates the gammonvalue (or actually the backgammon value in this case) incorrectly. 

can you append

show matchequitytable
show marketwindow
show gammonvalues

to your command file, and submit the output?

-Øystein


On Fri, Feb 16, 2018 at 5:43 PM, Terje Pedersen <address@hidden> wrote:
Hi!

I just ran into what looks like a gnu evaluation bug where gnu seems
to suggest that I should try to avoid backgammon when a gammon will
lose the match anyway. command file:

set player 0 human
new match 0
set output rawboard off
set xgid XGID=----BBCA-----A----B-B--eB-:0:0:1:51:0:3:0:5:10
move 24/19 18/17
next
previous
analyze move
show board

$ ./gnubg.exe -t -c commands.txt
GNU Backgammon 1.05.000  Nov 27 2016
Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004 by Gary Wong.
Copyright (C) 2015 by Gary Wong and the AUTHORS; for details type
`show version'.
This program comes with ABSOLUTELY NO WARRANTY; for details type `show
warranty'.
This is free software, and you are welcome to redistribute it under
certain conditions; type `show copying' for details.
Moves for gnubg must now be entered manually.
A new session has been started.
TTY boards will be given in ASCII.
The dice have been set to 5 and 1.
 GNU Backgammon  Position ID: PgAAALYLBDMMAA
                 Match ID   : cImmADAAAAAE
 +13-14-15-16-17-18------19-20-21-22-23-24-+     O: gnubg
 | X              X |   |    X        O  X | OO  3 points
 |                X |   |    X        O  X | OO
 |                  |   |             O    | OO
 |                  |   |             O    | OO
 |                  |   |             O    | OO
v|                  |BAR|                  |     5 point match (Cube: 1)
 |                  |   |                  |
 |                  |   |                  |
 |                  |   | X                |
 |                  |   | X  X  X          |     Rolled 51
 |                X |   | X  X  X          |     0 points
 +12-11-10--9--8--7-------6--5--4--3--2--1-+     X: terje


Cube analysis
2-ply cubeless equity  -2.238 (Money:  -2.039)
  0.086 0.000 0.000 - 0.914 0.771 0.440
Cubeful equities:
1. No double            -2.058
2. Double, pass         +1.000  ( +3.058)
3. Double, take         -2.430  ( -0.372)
Proper cube action: No double, take (10.9%)

Rolled 51 (-0.066):
     1. Cubeful 2-ply    24/18                        Eq.:  -1.850
       0.144 0.000 0.000 - 0.856 0.716 0.430
        2-ply cubeful prune [world class]
     2. Cubeful 2-ply    24/19 6/5                    Eq.:  -1.994 ( -0.143)
       0.106 0.000 0.000 - 0.894 0.735 0.627
        2-ply cubeful prune [world class]
     3. Cubeful 2-ply    24/19 7/6                    Eq.:  -2.015 ( -0.164)
       0.102 0.000 0.000 - 0.898 0.739 0.626
        2-ply cubeful prune [world class]
*    4. Cubeful 2-ply    24/19 18/17                  Eq.:  -2.065 ( -0.214)
       0.089 0.000 0.000 - 0.911 0.743 0.647
        2-ply cubeful prune [world class]
     5. Cubeful 2-ply    13/7                         Eq.:  -2.165 ( -0.314)
       0.071 0.000 0.000 - 0.929 0.780 0.641
        2-ply cubeful prune [world class]
     6. Cubeful 2-ply    13/8 6/5                     Eq.:  -2.180 ( -0.329)
       0.070 0.000 0.000 - 0.930 0.787 0.663
        2-ply cubeful prune [world class]
     7. Cubeful 2-ply    18/13 6/5                    Eq.:  -2.200 ( -0.349)
       0.060 0.000 0.000 - 0.940 0.783 0.692
        2-ply cubeful prune [world class]
     8. Cubeful 2-ply    7/2 6/5                      Eq.:  -2.206 ( -0.355)
       0.068 0.000 0.000 - 0.932 0.799 0.669
        2-ply cubeful prune [world class]
     9. Cubeful 2-ply    18/17 18/13                  Eq.:  -2.212 ( -0.361)
       0.057 0.000 0.000 - 0.943 0.781 0.700
        2-ply cubeful prune [world class]
    10. Cubeful 2-ply    18/13 7/6                    Eq.:  -2.229 ( -0.378)
       0.056 0.000 0.000 - 0.944 0.789 0.702
        2-ply cubeful prune [world class]

Any idea what is going on here? I am using gnu bg for evaluating moves
on Backgammon Studio when playing online matches and was hit in the
face with this double blunder which I was confident couldn't possibly
be correct. XG doesn't think it is much of an error:

    2. XG Roller++ 24/19 18/17                  eq:-2.2250 (-0.0057)
      Player:   7.58% (G:0.00% B:0.00%)
      Opponent: 92.42% (G:76.45% B:64.53%)


Best regards,
TP

_______________________________________________
Bug-gnubg mailing list
address@hidden
https://lists.gnu.org/mailman/listinfo/bug-gnubg


reply via email to

[Prev in Thread] Current Thread [Next in Thread]