Author: Christophe Theron
Date: 10:22:42 11/03/03
Go up one level in this thread
On November 03, 2003 at 10:04:32, Will Singleton wrote:
>On November 03, 2003 at 02:35:09, Gerd Isenberg wrote:
>
>>On November 03, 2003 at 02:33:02, Gerd Isenberg wrote:
>>
>>>On November 02, 2003 at 17:12:38, Will Singleton wrote:
>>>
>>>>On November 02, 2003 at 16:52:49, Gerd Isenberg wrote:
>>>>
>>>>><snip>
>>>>>>In the same vein, the following position has always been a nightmare for Tiger:
>>>>>>
>>>>>>[D]8/1KP5/3q2k1/8/6p1/8/8/8 b - -
>>>>>>
>>>>>>This position comes from a real game between the Modular Game System Sargon 2.5
>>>>>>and Mike III, played in September 1980 during the Personal Computer World Fair.
>>>>>>Mike III continued the game with a long series of checks leading to a draw.
>>>>>>
>>>>>>Chess Tiger is not smarter than Mike III here. It is something that I had fixed
>>>>>>in the 16 bits version, to the expense of some added complexity in the passed
>>>>>>pawns evaluation code. I have not transfered this code to the 32 bits version
>>>>>>because it was not general enough (add another black pawn and the code did not
>>>>>>work).
>>>>>>
>>>>>>I am interested in results of other (amateur and commercial) programs.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Christophe
>>>>>
>>>>>Hi Christophe,
>>>>>
>>>>>IsiChess on AMD XP2.6+ first shuffles around with Qb4+, Qxc7 and Qd7.
>>>>>After 5 seconds at depth 13 Qxc7 came up. Mate in 14 resp. 12 after one minute
>>>>>and 1:10. I guess a matter of won KPK eval.
>>>>>
>>>>>Cheers,
>>>>>Gerd
>>>>
>>>>Sure, but I'm not sure CT was referring to finding the mate as the problem. CT
>>>>seems to have some problem understanding that KQK is better than KQKP, that's
>>>>all I can figure.
>>>>
>>>>Will
>>>
>>you mean won KPK against KQPKP? I use interior node recognizers and assign
>>shlightly more than queen advantage in won KPK. Additionaly there is a
>>heuristic, that reduces score a bit (e.g. abs(delta material) / X) if a lot of
>>checks occur with "no progress".
>> ^^^^
>>Gerd
>
>I do that too, but it's constrained to several consecutive checks that don't
>reset the fifty-move counter. Seems to help in some positions, but I'm not sure
>how generally effective it is.
>
>Will
That's exactly what I have tried, with different values for X and the number of
consecutive checks needed to trigger it.
It has always weakened my program. Not by much, but I expected a minor gain, not
a minor loss!
I have seen Genius doing this for years, much to my despair... :(
It seems right, intuitively, but I can't get it to work effectively.
Christophe
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