Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Why Dr Robert Hyatt was a draw ? Thx Pablo Restrepo

Author: Uri Blass

Date: 23:58:57 06/14/05

Go up one level in this thread


On June 14, 2005 at 23:24:35, Robert Hyatt wrote:

>On June 14, 2005 at 23:20:36, Robert Hyatt wrote:
>
>>On June 14, 2005 at 21:53:11, Pablo Ignacio Restrepo wrote:
>>
>>>Doctor
>>>Robert Hyatt
>>>
>>>I wonder.
>>>Why Crafty made a draw ?
>>>Best Regard,
>>>Pablo Restrepo
>>
>>
>>Hard to say...
>>
>>if this was really a guest vs crafty game, Crafty plays a bit differently since
>>guests have no "rating" and Crafty has no idea how good or bad they are as a
>>chess player.  If you want to play from a real account, I can certainly set it
>>up so that this will be nearly impossible to do...
>>
>>
>>
>
>Looked further.  Classic case of a 3-fold repetition hidden by a hash table hit,
>that wrecked the search.  I'll look to see if there is a way to recognize this
>and prevent this particular case from haunting me.  It's a known problem for any
>program that uses a hash table however...  not just for Crafty.

Not exactly.

Using hash tables cannot hide repetition if it is used for better order of moves
or to save evaluations and not for pruning.

I also think that 3-fold repetition is not a problem if the program use hash for
pruning only when no 2-fold repetition happened in the game after the last
conversion.

Uri



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.