Re: [gnugo-devel] Re: [computer-go] SlugGo v.s. Many Faces

[David G Doshay <ddoshay@xxxxxxx>]

On Aug 26, 2004, at 2:47 AM, wagjan@xxxxxxxxxxxxxxxxx wrote:

> I am afraid, that there are many situation where the move which
> seems to be the second best at first sight is much better then the
> first. (Or the first leeds to a trouble, which is the same... :))
This is exactly why we consider many of GNU Go's highest ranked
moves as candidates and then do lookahead on each.

> And
> when this happend at 3rd ply, then searching the wrong line in 16
> deep is worthless.
This is the "common knowledge" we all learn from our first lessons
in tesuji and life/death problems. This is undoubtedly true when the
goal is optimal play for the correct reasons ... a great goal. But I
think that too many people fixate on this reasoning and neglect to
note that while the long term goal is optimal play for the correct
reasons, there is also the short term goal of simply playing better.
It is clear that this non-optimal once-branched and then linear
deep lookahead (that we implemented just because it is an easy
way to start) in fact plays better, even if not optimally, for the right
reasons, or even with complete or correct information.

I am fully confident that when we start branching in the lookahead
paths we will more accurately evaluate the paths and thus play
better. But once we found that this method worked as well as it
does, we decided to gather statistics before moving on to other
methods we assume are better.

> It is not supprising that it could be stronger by 3-
> 5 kyu against himselt,
Because we win about 70% with 5 stones in "self play" against
GNU Go, I'd say we picked up about 6 stones of strength, but as
previously noted this is because we correctly predict GNU Go's
responses. To lessen this effect we have played against GNU
Go set at level 15 while we use level 10.

> but it is interesting for me that it is
> significantly stronger against Many Faces.
Here we pick up perhaps 3 stones ... the data is still being collected.

> I guess that 16 ply 'very
> narrow' search can not help more then 1 kyu against human.
Time will tell.


Cheers,
David


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