Re: [Bug-gnubg] never too good?

[Joern Thyssen]

On Fri, Aug 02, 2002 at 07:07:00PM +1200, 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.

Assuming that both players play perfect....

> 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.

I agree. 

When I get home, I'll try doing a rollout with gnubg and see if I can
reproduce the result, so eliminate possible bugs.

What were your rollout settings?

Jørn

-- 
Joern Thyssen, PhD
Vendsysselgade 3, 3., DK-9000 Aalborg, Denmark
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