Computer Chess Club Archives




Subject: Re: Fixed

Author: Frank Phillips

Date: 13:10:01 02/20/02

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On February 20, 2002 at 12:48:06, Steve Maughan wrote:

>Thanks for the help everyone!
>I've implemented the idea I outlined and this has fixed the problem.  However
>effectively I ignore possition where I cannot add a hash entry without
>overwriting another.  This means that there is currently the possibility of a
>draw not being detected.  I'll probably test a rehashing mechanism.

Just stick the entry in the next available slot (that has a hash signature of
zero).  The debug tests I did never showed more than a few re-hashes - once it
was working properly.

I changed to this method from a simple array list following Bruce's description,
because it seemed so elegant with the possibility of speeding up detection in
the endgame - when the list approach might have many entries to check.

After falling for the obvious trap of not always removing an entry when exiting
ABsearch() early, it seems to work fine.

I noticed no significant speed loss (or speed up) in the short middle game test
I use.


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