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Subject: Re: Chesstiger have a problem with FINE 70 position !?

Author: Uri Blass

Date: 08:03:13 06/20/03

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On June 20, 2003 at 10:17:10, Ulrich Tuerke wrote:

>On June 20, 2003 at 09:37:14, Uri Blass wrote:
>
>>On June 20, 2003 at 09:12:57, Ulrich Tuerke wrote:
>>
>>>On June 20, 2003 at 07:34:03, Uri Blass wrote:
>>>
>>>>On June 20, 2003 at 07:29:35, Mike Byrne wrote:
>>>>
>>>>>On June 20, 2003 at 06:15:09, Joachim Rang wrote:
>>>>>
>>>>>>On June 20, 2003 at 05:05:24, Vincent Lejeune wrote:
>>>>>>
>>>>>>>
>>>>>>>I'm running a test with Chesstiger 15 and the Valentin Albillo test set (see
>>>>>>>http://www.talkchess.com/forums/1/message.html?301806) and what a surprise
>>>>>>>Chesstiger have a problem with the first position the well known FINE 70 (Kb1!);
>>>>>>>Crafty, Fritz, Hiarcs have no problem with this position; so why CT ? hashtable
>>>>>>>weakness, pruning weakness or somehting else ? Christophe, an idea ?
>>>>>>>
>>>>>>>>>
>>>>>>>I will publish the result for all positions later Celeron@875, 96 MB hash, 15
>>>>>>>min/pos
>>>>>>
>>>>>>
>>>>>>DeepSjeng has also Problems. At least in beta stage when I tested the program.
>>>>>>Gian-Carlo replied to my message with the argument, that tuning an engine for
>>>>>>this position makes it weaker in general pawn endgames. I'm sure the views
>>>>>>differ on that position but maybe Theron agrees with Gian-Carlo that this
>>>>>>specific position is an artificial one.
>>>>>>
>>>>>>regards Joachim
>>>>>
>>>>>this position is a question of search not tuning...
>>>>
>>>>I think that GCP talked about tuning the
>>>>extension and pruning rules.
>>>>
>>>>I can imagine that a change in the pruning rules that is productive for other
>>>>positions is not productive for this position.
>>>>
>>>>I do not believe that it is impossible to fix the problem in a productive way
>>>>and I guess that the real reason is that in the same time of fixing the program
>>>>it is possible to do bigger improvements.
>>>
>>>I don't think that solving this position is a matter of pruning or extensions,
>>>since Comet could solve it on a 16 MHz 80386 in a few seconds.
>>
>>
>>It only proves that it is a matter of pruning because Comet had not the same
>>pruning that tiger or sjeng had.
>
>No, it doesn't. As I said, solving this position is not a question of pruning or
>extending. The question is how to calculate a secondary index to the hash table
>when the default index points to storage which is already in use.
>
>I suspect very much that Chris and GCP can very easily improve their engines in
>positions of this kind by having a closer look to their replacement schemes.
>
>Uli

I did not claim that it is not easy to solve the position without pruning and
extensions.

I claim that it is possible not to solve the position because of adding a new
pruning rule.

Movei cannot solve it because of different reason(not using hash tables for
pruning) but I believe that Chris and GCP do not do it.

I have reasons not to improve this at this point because I feel that doing it
may limit my possibilities to try different ideas than other programs.

I have a lot to improve but even at this point movei is strong enough to have
practical chances against everything(the best result that I got from testers was
beating yace padderborn 4-2 at 40/40 time control but I know that movei is
clearly weaker than yace at this point)

Uri




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