Author: Christophe Theron
Date: 11:28:36 06/15/02
Go up one level in this thread
On June 15, 2002 at 13:44:06, Russell Reagan wrote:
>On June 15, 2002 at 11:36:29, Christophe Theron wrote:
>
>>About the "fork" example: I would not treat it by evaluation. I have tried and
>>it does not work. The solution of this problem must be found in search or
>>QSearch improvements.
>
>Why doesn't it work? It seems to me that as long as you are able to hammer out
>the details of detecting forks and special cases you should be able to implement
>this (or any other tactical recognition) statically in the evaluation function.
>
>Of course, I have never tried it myself, so you surely know better than I do,
>but I'm curious if you could provide us with some information as to WHY it won't
>work. Is it because there are too many special cases to handle to make it
>accurate?
>
>Thanks,
>Russell
It is because there are a lot of special cases to handle. If you want to
substract the value of a whole piece from your evaluation, you'd better be sure
about what you do, or else you will screw up many times.
So it's hard to write and consumes a lot of processing time.
You end up with something really expensive in term of processor time, that you
have to do at every leaf node or almost, and that is useful (if it works) only
in a tiny fraction of the positions you examine.
It's a clear loser.
There are more generic search algorithms, which take care not only of forks but
also of many other tactics, which are less expensive computationally, and which
are a much better solution for this problem.
In general, trying to take tactics into account in the evaluation function is a
bad idea.
Christophe
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