Author: enrico carrisco
Date: 15:28:17 01/20/06
Go up one level in this thread
On January 20, 2006 at 16:14:31, Vincent Diepeveen wrote: >On January 19, 2006 at 08:10:34, Vasik Rajlich 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. >> >>Yes, what you omit is just as important of course. >> >>A game like Zappa-Rybka would be much more likely to be played as black by >>someone like Fischer than someone like Tal. It's not because Tal doesn't know >>the basics about a queenside pawn majority. > >Fischer played very classical openings, Rybka on other hand is good in modern >positions. > >Fischer took big risks on kingside sometimes, Rybka never takes risks there. > >In that sense, Rybka is a very ugly player from human viewpoint are. > >Of course Rybka is not unique there. Most engines qualify there :) > >I remember Fernando comparing it with Karpov. However Karpov is a very >positional player, and Rybka isn't. There is a dozen engines more positional as >they have more knowledge (which of course means you could have potentially more >bugs, i agree in that respect with Chrilly, but it also means they have more >potential to play strong in future if those bugs ever get fixed). Shredder is >100x closer to Karpov than Rybka is. > >Rybka compares well with the Richard Lang style programs from a decade ago, in >term of style. > >What we do know already for many years is that tournaments in computerchess are >won easier by passive bugfree play, than by agressive attacking play. > >Shredder and Genius are good examples there. Fritz3 in its glory days was very >passive too. > >It is a race against bugs in computerchess always, in that sense you're doing a >superb job currently with Rybka. Very bugfree play. > >>I suspect Hydra will have a harder time than Rybka playing a position like this, >>but then again Rybka will have a harder time in some other types of positions. >>Fortunately in chess we have a way to settle these things. >>Vas > >Odds are of course zero that we'll ever meet Nimzo1998-on-stereoids or Fritz in >an official tournament ever again. Well that is, unless someone manufacturers >some real fast 'pocket pc' in which case Pocket-Fritz version 10.0 might win. >But hey, we might also know that under a different name... ...as Shredder 10. > >However i do appreciate the fact that one author is saying the truth about the >other author. > >Any claim of having a lot of knowledge in rybka, which for the average person >suggests it has more than others, must be proven of course and the obvious proof >which everyone can see in your assembly code is that it has real little. So it >was a clear lie. The "advocate of the devil" type of explaining things is not >relevant. > >A claim can be very valid from juridical viewpoint but very wrong from social >viewpoint. > >Chrilly clearly pointed that out for which we have to thank him. > >Please in future remember the big difference between lying, juridical non-lying >and marketing claims. There is a big difference between the two. A good >dissassembly specialist like Chrilly, his findings there are very valid. > >Perhaps take over some marketing slogan from Chessbase a few years ago: > "Rybka learns through search". > >Nothing wrong with that. > >By the way, it wouldn't hurt to show what you do in search, all the top 20 >programmers gonna debug it anyway in your program, the top 2000 however which is >in this forum who can't read assembly as well as Chrilly nor Frans, they like to >know :) > >Thanks, >Vincent It's interesting to see what the non-manipulated KN/s of Rybka was 1.75 years ago. Perhaps that project was scrapped shortly thereafter... http://chessprogramming.org/cccsearch/ccc.php?art_id=356880 http://chessprogramming.org/cccsearch/ccc.php?art_id=356884 -elc.
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