Re: [Bug-gnubg] some problems

[Jim Segrave]

On Tue 20 Jul 2004 (00:56 +0200), max-d wrote:
> Hi !
> just a little come back to backgammon to tell you how GNUBG's UI (and engine
> of course) is great !
> 
> some problems though..
> - i often have crashes when analysing 2plies
> (MS windows 98 356Mb )

Could you tell me what version you are running? There have been
versions with errors in analysis, but I think those are currently
pretty much fixed

> - UI and whole system crash when i try to use 3D board.

Again - how recent is your version? I'm no expert on Windows and video
cards, but some of the readers of this list may be able to help you
with this.

> - an incredible but probably well known mistake played by Parlorbot on FIBS
> this evening ...
> please see move 14 ,2 plies analysis agrees
> Thanks for your work !!

I must be missing something - if you are referring to the 24/18 9/4,
then not only does 2 ply agree, rollouts do as well. The alternative
play 24/13 loses about 9% less often, but those losses are more than
twice as likely to be gammons. A two ply rollout is very slow (about 5
hours on my machine, but after a small number of games 30 or so, the
numbers are already starting to look like the 0 ply ones. Leaving one
chequer back on the opponent's bar gives 21 shots (not good), but no
other blots are left lying about and there are only 3 chequers to
bring in to save the gammon. Moving the back chequer up to the 13
point reduces the immediate hits to 15, but with a 5 point board,
coming in isn't easy and there are lots of chances to pick up the
second blot. There are 4 chequers to bring home, all factors that run
the gammon chances way up. I think gnubg is right in its choice of
plays.


The score (after 1 game) is: ParlorBot 1, You 0 (match to 5 points)
Match Information:

Move number 26: O to play 65

    GNU Backgammon  Position ID: tttEAAO258gAIA
                    Match ID   : AQG3ABAAAAAA
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+  O: ParlorBot (Cube: 2)
    |    O  O  O  X  O |   |       O     O    |  1 point
    |    O  O  O  X  O |   |             O    |  Rolled 65
    |          O     O |   |                  |  
    |          O       |   |                  |  
    |                  |   |                  |  
    |                  |BAR|                  |^ 5 point match
    |                  |   |                  |  
    |                  |   |                  |  
    |          X       |   |                  |  
    |    X  X  X  X  X |   |                  |  
    | O  X  X  X  X  X |   |    X        X    |  0 points
    +24-23-22-21-20-19------18-17-16-15-14-13-+  X: You
Pip counts: O 99, X 103

* ParlorBot moves 24/18 9/4

Cube analysis
2-ply cubeless equity  -0.513 (Money:  -0.467)
  0.307 0.062 0.002 - 0.693 0.145 0.002
Cubeful equities:
1. No double            -0.410
2. Double, pass         +1.000  ( +1.410)
3. Double, take         -1.784  ( -1.374)
Proper cube action: No redouble, take (49.3%)

Rolled 65 (-0.027):
*    1. Rollout          24/18 9/4                    Eq.:  -0.286
       0.342 0.038 0.003 - 0.658 0.104 0.003 CL  -0.435 CF  -0.286
      [0.002 0.004 0.001 - 0.002 0.003 0.001 CL   0.006 CF   0.008]
        Full cubeful rollout with var.redn.
        648 games, Mersenne Twister dice gen. with seed 2032818251 and 
quasi-random dice
        Play: 0-ply cubeful [expert]
        Cube: 0-ply cubeful [expert]
     2. Rollout          24/13                        Eq.:  -0.346 ( -0.060)
       0.396 0.045 0.010 - 0.604 0.233 0.006 CL  -0.524 CF  -0.346
      [0.002 0.004 0.003 - 0.002 0.003 0.001 CL   0.006 CF   0.009]
        Full cubeful rollout with var.redn.
        648 games, Mersenne Twister dice gen. with seed 2032818251 and 
quasi-random dice
        Play: 0-ply cubeful [expert]
        Cube: 0-ply cubeful [expert]
     3. Cubeful 2-ply    9/3 6/1                      Eq.:  -0.535 ( -0.249)
       0.271 0.060 0.001 - 0.729 0.163 0.004
     4. Cubeful 0-ply    24/18 6/1                    Eq.:  -0.774 ( -0.488)
       0.283 0.049 0.001 - 0.717 0.342 0.007
     5. Cubeful 0-ply    11/6 9/3                     Eq.:  -1.000 ( -0.714)
       0.173 0.036 0.000 - 0.827 0.288 0.009


-- 
Jim Segrave           address@hidden