Computer Chess Club Archives


Search

Terms

Messages

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

Author: Ulrich Tuerke

Date: 07:17:10 06/20/03

Go up one level in this thread


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 guess that GCP can easily change Sjeng not to have the pruning rules that it
>has in order to solve it but the problem is that sjeng is going to be weaker
>only in other pawn endgames.
>
>I do not know but I guess that the pruning is about pruning lines that lose a
>lot of tempos.
>
>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.