Re: [Bug-gnubg] Errors in evaluation of races with backgammons

[Joseph Heled]

Sorry, that was a 1 point game, this is a 0/0 in a 7 point match, so
seems normal.

Position ID:    /wgAWBz/AAAAAA
Match ID:       cAngAAAAAAAA

Evaluator:      Race


        Win     W(g)    W(bg)   L(g)    L(bg)   MWC       Cubeful
static: 1.000   1.000   0.678   0.000   0.000    67.61%    67.61%
 1 ply: 1.000   1.000   0.678   0.000   0.000    67.61%    67.61%
 2 ply: 1.000   1.000   0.681   0.000   0.000    67.64%    67.64%



On 27 February 2012 20:46, Joseph Heled <address@hidden> wrote:
> Not sure how to set up gnubg to evaluate higher plies. This is after
> manually editing the position
>
> Position ID:    /wgAWBz/AAAAAA
> Match ID:       cAkgAAAAAAAE
>
> Evaluator:      Race
>
>
>        Win     W(g)    W(bg)   L(g)    L(bg)   MWC       Cubeful
> static: 1.000   1.000   0.678   0.000   0.000   100.00%   100.00%
>  1 ply: 1.000   1.000   0.678   0.000   0.000   100.00%   100.00%
>  2 ply: 1.000   1.000   0.799   0.000   0.000   100.00%   100.00%
>
> On 27 February 2012 19:33, Joseph Heled <address@hidden> wrote:
>> On 27 February 2012 19:09, Philippe Michel <address@hidden> wrote:
>>> On Mon, 27 Feb 2012, Joseph Heled wrote:
>>>
>>>> clearing checkers from the back is not the same as bearoff - you *can*
>>>> move any checker you want.
>>>
>>>
>>> Embarrassing. You're right of course and in my example 3s and 4s can
>>> certainly be played in a different way than in a bearoff.
>>
>> An easy mistake to make. Still ....
>>
>> Using some python trickery it is possible to get the true backgammon
>> figure. "true" here means that you always make the optimal move which
>> minimises the probability of backgammon.  The number is 40615026 /
>> (36^5) = 0.6716982730973429
>>
>> Now, nngnu gives those numbers for plies 0 to 5
>>
>>  0ply  0.6775242686271667
>>  1      0.6775177717208862
>>  2      0.6775177717208862
>>  3      0.6775176525115967
>>  4      0.6717002391815186
>>  5      0.6716980934143066
>>
>> which I am happy about, but it seems that *there is* some problem in
>> gnubg, which gives different numbers for different plies.
>>
>> I think someone should take a good look at this!
>>
>> -Joseph