[computer-go] How to design the stronger playout policy?

[Don Dailey]

I think Dave Hillis coined this term "heavy playouts."      

In the first programs the play-outs were uniformly random.   Any move
would get played with equal likelihood with the exception of eye-filling
moves which don't get played at all of course.

But it was found that the program improves if the play-outs are somewhat
"managed".   So Dave starting calling the original formula "light
play-outs" and the slower but better method "heavy play-outs."  

And yes, it slows down the play-outs.   Still, the play-outs seem to
require a good bit of randomness - certainly they cannot be
deterministic and it seems difficult to find the general principles that
are important to the play-out policy.  

- Don



Mark Boon wrote:
>
> On 5-jan-08, at 11:48, Gian-Carlo Pascutto wrote:
>> >
>>> Would you explain the details of the playout policy?
>>
>> (1) Captures of groups that could not save themselves last move.
>> (2) Save groups in atari due to last move by capturing or extending.
>> (3) Patterns next to last move.
>> (4) Global moves.
>>
>
> Is this what is meant by 'heavy playout'?
>
> I suppose it slows down the playout considerably. Just keeping track
> of actual liberties instead of pseudo-liberties should probably be
> three times slower by itself. But in itself I think the idea is
> interesting. I've always felt programming Go would go towards several
> layers of playing engines. Each one a bit more sophisiticated built on
> top of a more primitive one.
>
> Mark
>
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