Re: computer-go: abstract info and neural nets

[Heikki Levanto <heikki@xxxxxx>]

On Fri, Jan 11, 2002 at 05:59:40PM -0000, Julian Churchill wrote:
>  I am using neural networks as part of a Go playing program I am writing and
> so far have only fed the nets with basic information, i.e. the board
> contents. I have noticed that other neural net programs (NeuroGo and Nicol
> Schraudolph et al.) used much more complex approaches, inputting information
> calculated about strings and groups, such as number of liberties and
> connection possiblities.

I am sorry, but I do not see much future in just feeding the board position
to a neural network, and expecting it to learn anything from it. NNs are
good at recognising patterns. They can even generalize from the known
patterns and correctly classify patterns that are a bit off. Unfortunately,
there are two problems in trying to use this in evaluating go positions:

1) There are so many whole-board patterns to learn. The board is huge, and
without any "intelligent" grouping of stones all you can do is to recognize
the overall pattern. There are so very many of them - enough to argue that
no two players ever play the exactly same game. If you only see your
patterns once, it is hard to learn from them.

2) Even small differences in the position can totally change the value of
the position. If two large one-eyed groups can be connected, they are very
valuable. If the connection can not be made, they are a huge win to the
opponent. The feasibility of this connection can depend on a single stone
far removed from the position (a ladder breaker, for example).


Whole-board pattern learning may be useful in the very opening, but
unfortunately it doesn't help anything to play a good opening if you can not
continue with even a modest middle and end game.

You may have some luck on very small boards, but I wouldn't bet even on
that.


Of course, I may have misunderstood what you are trying to do, or I may have
misunderstood the neural nets - I don't have much experience with them. Or I
may be simply wrong. Keep us posted, if you make progress!

Good luck!

	Heikki



-- 
Heikki Levanto  LSD - Levanto Software Development   <heikki@xxxxxxxxxxxxxxxxx>