On Tue, Oct 30, 2007 at 08:07:49PM +0100, Heikki Levanto wrote:
> On Tue, Oct 30, 2007 at 02:45:56PM -0400, Jason House wrote:
> > Similarly, I've been in won games and gotten bitten by a tesuji by the
> > opponent. If I had been just a bit safer in my play, I could have had a
> > comfortable win. Similarly, reasonable MC bots solidify the core to win
> > rather than try to keep everything.
>
> I would like to think so too, but that is not what I am seeing. In my own
> small experiments, I saw this kind of things often enough (bottom edge of the
> board):
>
> 3 O O O O O O O + + + + + +
> 2 O X X X X X O O O O O O O
> 1 O X + X + X + X X + X X O
> A B C D E F G H J K L M N
>
> Any "sane" human player would connect at G1 first, and K1 later. But to a MC
> player, those two are very close to equal, as long as the game seems to be
> decided by five points or more, or there is another similar situation on the
> board, and the program can be sure of getting one of them.
>
This is expected for a monte-carlo evaluator. Let assume that any other
play on the board cannot change the result, and black is more that 5
points in advance, you can play either move theresult will be same : a
victory. The only thing that will change is the score of the game, but
in most MC engine the score is not used, only the result. So you can
make all simulation you want, the score for g1 and k1 will be same : 1.0
MC tend to choose the safer path in the tree. At a given node, if you
have only 2 possible moves :
- the first one is a clever tesuji which lead to a 50pt win but need
to folow a strict sequence of 10 moves or you loose,
- the second one assure you a small victory of 0.5pt even if you make
some mistakes later in the game.
Your program will choose the second move because more random simulation
lead to a win in the second case.
The first type of move is the ones that you can look in professional
games where pro are always on the line and any mistakes can make you
loose the game. Second one reflect the safest way of playing when you
have some advance in the game, and when you just want to win the game.
You just make your group fully alive and solid, and you prevent any
invasion from your oponent.
Tom
--
Thomas Lavergne "Le vrai rêveur est celui qui rêve
de l'impossible." (Elsa Triolet)
[EMAIL PROTECTED] http://reveurs.org
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