Re: [Bug-gnubg] Even, odd and half plies (WAS: New Contact Net Error Rates)

[Nis]

--On Thursday, February 27, 2003 08:08 +1300 Joseph Heled 
<address@hidden> wrote:

> It seems your idea has lot's of merit. Sorry for being skeptical at first.

Are you saying that I have thought up something which might improve the 
actual playing strength of gnubg? Woohoo!

> 107485 contact benchmark positions
>   0Ply error - 0.01079  (w = 0)
>   1Ply error - 0.00956  (w = 1)
>
>   w * ply1 + (1-w) * ply0
>
>    w = 0.5   error - 0.009176
>    w = 0.75  error - 0.009155
>    w = 0.625 error - 0.009066
>    w = 0.57  error - 0.009070
>    w = 0.67  error - 0.009071
>
> Conclusions:
>
>    - 1ply does play contact positions better after all.
>    - 1.5 ply is better yet. The best w is around 0.6

Just to make sure: The above is what I called 0.5-ply (since it is the 
average of 0- and 1-ply).

> Works for crashed as well, with w somewhere in the 0.4 - 0.5 range.

Could you post the numbers? I am especially interested in the crashed 
positions - since this is where the largest problems have been reported
...

I would also be VERY interested in seeing the results from including 2-ply 
evaluations, using these two formulas:

w * ply2 + (1-w) * ply1

and

w1 * (1 + w2) * ply2 + (1-w1) * ply1  - w2 * w1 * ply0

(w1 and w2 both around 0.5)

> So, if we implement such a thing, we will need it to be per class. w may
> be per class, but that is not very important, as w=0.5 will do quite well.

Please note: The numbers above shows that the _idea_ actually works. I 
think the best implementation will be using reduced evaluation - probably 
50% reduction.

--
Nis Jorgensen
Greenpeace
Amsterdam