Re: [Bug-gnubg] never too good?

[Joseph Heled]

For example,

Joseph Heled wrote:
> 
> Øystein O Johansen wrote:
> >
> > > Your opponent has borne out at least one
> > > one. It is possible the positions is no-double,
> > > double/take and double/drop.
> > > But can it ever be too-good-to-double/drop?
> >
> > Yes, I think you're right. These are the only
> > three cube decisions that makes sense. Valid for
> > money game and match play. I can't think of any
> > known paradoxes that invalidates the statment
> > either.
> >
> > -Øystein
> 
> This is the position that prompted my temporary self doubt. (number 55 in
> doubles.dat 0000)
> 
>  GNU Backgammon  Position ID: BgAC2HZ7AAAEAA
>                  Match ID   : MAGgAAAAAAAA
>  +12-11-10--9--8--7-------6--5--4--3--2--1-+     O: gnubg
>  |          X       |   |    O  O  O  O  O | O   0 points
>  |                  |   |    O  O  O  O  O |     On roll
>  |                  |   |    O     O       |
>  |                  |   |    O             |
>  |                  |   |                  |
> ^|                  |BAR|                  |     5 point match (Cube: 1)
>  |                  |   |                  | XX
>  |                  |   |                  | XX
>  |                  |   |                  | XX
>  |                  | X |             X    | XX
>  |                  | X |             X  O | XX  0 points
>  +13-14-15-16-17-18------19-20-21-22-23-24-+     X: joseph
> 
> My cubefull rollout gave
>   ND  59.428%
>   D/T 59.754%
> 
> With D/D 57.5%, this is strange. Without gammons/bg's, ND should be <= D/D.
> I think this means X is making a great number of bad takes, or in other words,
> this position (and others like it) are a good source for finding positions 
> where
> GNUbg makes cube errors.
> 
> -Joseph
> 
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Game number 1

x (white, 0 pts) v o (red, 0 pts) (Match to 5)

---

Move number 0: Red doubles

Pipcounts: Red = 43, White = 70

• x accepts

Cube action equity

576-Games  

Equities: Money  0.933     

0.0%   0.0%  96.7%     3.3%   0.0%   0.0%  

  Match win probabilities:

No Double	Double/Take	Double/Drop
57.57%	63.48%	57.50%

Cube action: Double, pass

---

fibs2html 0.4, Fri Aug  2 19:14:29 2002

---

Game number 1

x (white, 0 pts) v o (red, 0 pts) (Match to 5)

---

Move number 0: Red doubles

Pipcounts: Red = 43, White = 70

• x accepts

Cube action equity

0-Ply  

Equities: Money  0.573     

0.0%   0.0%  78.6%    21.4%   0.0%   0.0%  

  Match win probabilities:

No Double	Double/Take	Double/Drop
56.27%	56.97%	57.50%

Cube action: Double, take

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fibs2html 0.4, Fri Aug  2 19:14:38 2002