[EMAIL PROTECTED] wrote:
Hello all,
I am wondering about Go in 7x7. I know that the game in this size has no real
interest in itself. However, I think that the level of computer go programs
is much higher in 7x7 than in 9x9, and it could be interesting to see until
where we can go in 7x7.
There was a discussion on this list recently about the level of CrazyStone in
7x7, and also (perhaps not on this list, only on kgs I don't remember) of
Magnus saying that the level of Valkyria was very good on 7x7. I am wondering
if we can make a player that beats almost all humans in 7x7?
I think Crazy Stone does, already. Look at its history on KGS. It won
against strong dan players, and even a 5-dan professional. Crazy Stone
works with wine in Linux, if you wish to try it by yourself.
I have tried to put MoGo on kgs in 7x7, but it looses quite a lot of games.
Ok, I have put only 5 minutes time, so it plays quite fast, and perhaps could
be better with more time, but it is clearly far from a really good player.
A lot of the strength of Crazy Stone comes from its hand-made opening book.
I have implemented a meta-UCT (that means that instead of playing a random
game after the tree, you make MoGo playing against itself) to generate an
opening database. I have made this meta-UCT 100% parallel for a cluster (as
the evaluation is now so costly, parallelisation is trivial). I can dedicate
quite a lot of computers to this task as I have access to a cluster.
So I wonder if you think that this meta-UCT can be effective to generate a
good opening database, and this way manage to have a really good computer Go
player in 7x7 ?
Perhaps usual UCT exploits too much for this task, because my experiments show
that the beginning of the tree is quite narrow. Here are the first moves: D4
D5 E5 C4 D3 C5. I have no idea if it is very stupid or normal.
Remi was saying that the right komi for 7x7 is 9, but I have made my
experiments with komi 7.5, and the meta-UCT predicts that black is almost
always loosing. Is it because the blacks moves are very bad?
Yes. I am very confident that 7.5 is too small.
By the way, using an integer komi is interesting because the possible
outcomes are not binary any more. The game can be a win, a draw, or a
loss. I have the feeling that UCT works really very well when the
outcome is binary. Introducing the possibility of a draw significantly
changes the nature of the problem. My feeling is that UCT becomes too
selective in that case.
To conclude, I think this question of 7x7 is interesting because we can
perhaps have a very good player. What do you think? If you have good ideas to
make the meta-UCT generate a good database, I can dedicate a lot of CPU to
this task, and would interested to see what happen.
I don't believe it can beat hand-made book preparation, but I may be wrong.
Rémi
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