Re: [Bug-gnubg] Removal of absolute fibs ratings

[Christian Anthon]

I agree assigning skill levels to backgammon players is a very complex
matter and what is difficult varies from player to player. As to your
position you must remember that gnubg counts close doubles and not
non-obvious cube actions. In the position the cube actions may be
non-obvious, but they certainly aren't close.

Christian.

On 9/4/06, Albert Silver <address@hidden> wrote:
> I think it is rather complicated. Admittedly, some doubles with such
> an equity difference can seem absurd, but many will leave players very
> much in doubt, especially if they are dependent on the score. Here is
> an example:
>
>  GNU Backgammon  Position ID: 7LYBAGPN3QYgIA
>                  Match ID   : MAFgAAAAAAAA
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+     O: GNU
>  |                O |   | O  O  O  X  O  O |     0 points
>  |                O |   | O  O  O  X  O    |     On roll
>  |                  |   |    O  O          |
>  |                  |   |                  |
>  |                  |   |                  |
> ^|                  |BAR|                  |     3 point match (Cube: 1)
>  |                  |   |                  |
>  |                  |   |                  |
>  |                  |   |       X          |
>  |                X | X | X  X  X  X       |
>  |             O  X | X | X  X  X  X     O |     0 points
>  +13-14-15-16-17-18------19-20-21-22-23-24-+     X: Albert
>
>
>
> Cube analysis
> 2-ply cubeless equity  +0.3741 (Money:  +0.2537)
>    51.93%  29.02%   1.08% -  48.07%   8.47%   0.14%
> Cubeful equities:
> 1. No double            +0.3045
> 2. Double, pass         +1.0000  ( +0.6955)
> 3. Double, take         +0.0365  ( -0.2681)
> Proper cube action: No double, take (27.8%)
>
> This situation occured in a game of mine, and my opponent sent the
> cube. It is a blunder to send, over 0.250, and a larger one to pass. I
> had no idea what to do, and analyzed quite some time before taking.
> I've analyzed it and understand better, but even if it is in blunder
> territory, I don't think that it is so obvious to all, despite the
> potential size of the mistake.
>
> Albert
>
>
> On 9/4/06, Christian Anthon <address@hidden> wrote:
> > The threshold of 0.25 seemed too large for common sense, far too many
> > doubles very counted as being close, but also the function was plain
> > stupid and hard to understand. For example all too-good positions were
> > counted in for some reason. The threshold could be set back to 0.25
> > for counting of the doubles, but it would still be difficult to guess
> > the average relation between the old and current versions of the
> > function.
> >
> > Christian.