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Subject: Re: The superior Rybka chess knowledge

Author: Ryan B.

Date: 01:24:58 01/21/06

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On January 18, 2006 at 20:16:43, Ryan B. wrote:

>On January 18, 2006 at 13:34:17, Chrilly Donninger wrote:
>
>>After playing several engine matches against Rybka (chess programming is a
>>rather boring job) I have come to the conclusion: There are a few special
>>evaluation features of Rybka which are really unique. It is interesting that
>>some seamingly relative unimportant feature appear regularily on the board. The
>>opponent has no idea of this feature and does not prevent it. And the search
>>always finds a way to reach the pattern. Rybka has e.g. some special passed pawn
>>evaluation terms. I do not want to tell the details, but the game Zappa-Rybka,
>>Paderborn 2005 is a prototype game for one of these special features.
>>But the main chess-knowledge which sets Rybka appart from other engines is
>>ignorance. The omission of features which other engines have incorporated.
>>I have written a longer article for the German "Schachkalender 2006". The
>>message of this article is: Most of the published chess knowledge is completly
>>useless. Give your favorite chess-enemy your chess-books as a present. They will
>>do some harm on his play.
>>Rybka seems to be to prove of this hypothesis. If a feature is - in a given
>>position - correct, it is of course an advantage if a programm has implemented
>>it. But if its wrong, the programm hangs on an advantage which does no really
>>not exist. Or even worse, it sacrificies another advantage to reach the pattern.
>>
>>I realized the principle: "It is sometimes more important to remove features
>>than to add ones" several times in the Hydra project. E.g. Piece-Square Tables
>>are generally considered as a "must have". Strong Chessplayers do not like them.
>>It is very unnatural for them to evaluate a piece without considering the
>>context of the other pieces. It took some time till GM Lutz convinced me to
>>remove them in Hydra. And indead, the programm played considerably stronger with
>>Piece-Square.
>>Insofar is the Rybka approach intelligent ignorance.
>>
>>Chrilly
>>
>>P.S.: The omission of Piece-Square-Tables is a feature of Hydra. I do not state,
>>that Rybka as skipped this feature too.
>
>How much do you think the end of PV search helps in Rybka?  I am surprised at
>the tactical shots it catches but I think Rybka would still be strong without
>it.  Interesting idea at least.
>
>Ryan


I guess I got it wrong?  More like this?
http://chessprogramming.org/cccsearch/ccc.php?art_id=319630

Ryan



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