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descriptionThe Rybka Case - Greatest Injustice in Computer Chess History EmptyThe Rybka Case - Greatest Injustice in Computer Chess History

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The ICGA document neglects to mention a group of chess programmers who did their own investigation with findings that were presented to the ICGA (pre-dating the document). The ICGA then systematically refused to comment on this contra investigation document or its contents.

Unlike the ICGA Rybka investigators (Zach Wegner & Mark Watkins) the contra investigation highlights many important points that Wegner and Watkins missed, such as errors in the reversed engineered material which were deliberately withheld from the documents and deliberately withheld by the ICGA Secretariat from the ICGA investigation Panel.

Whereas the ICGA Rybka investigators could only find 5-7 differences between the evaluation of Fruit and Rybka, the contra investigation shows a long list, in short:

Every major evaluation ingredient is coded differently, mobility, king safety, passed pawns, double pawns, backward pawns, Rybka is missing Fruit's late endgame knowledge, Rybka has a material table – different from Fruit. Rybka does not contain Fruit's quad function, Rybka’s trapped bishop evaluation is different, rook evaluation is different, bishop pair evaluation different and most importantly, Fruit evaluates in stages in a unique way whereas Rybka adds directly to its score (as every other program on the planet does).

Other key differences between Fruit and Rybka:

   Time control is different
   Fen parsing is different
   Rybka extracts the mainline from the transposition table (TT), Fruit via the classic triangle table
   Rybka 1.0 beta displays a mainline of maximum of 10 moves, Fruit produces much longer variations
   Rybka uses a bitboard board representation whereas Fruit is mailbox
   Rybka’s pawn value is 3200 (which is unique), Fruit uses the classic value of 100
   The order in the evaluations of Fruit and Rybka are not similar
   Rybka has lazy evaluation, which is absent in Fruit
   Futility pruning is different between the two programs
   Rybka uses Late Move Reductions (LMR) whereas Fruit uses history reductions
   Fruit uses a history table which is absent Rybka.
   Fruit only has one evaluation table (king safety) while Rybka has many
   The two programs have a different move format
   Rybka does not handle promotions to minor pieces
   The two programs have different hash table code
   They have different handling of repetitions and the 50-move rule in search
   Fruit maintains piece-lists which are not present in Rybka
   Fruit maintains a pseudo "bitboard" for pawns, Rybka has the real thing.
   Contrary to Fruit, Rybka needs to update 4 rotations of occupancy bitboard
   Contrary to Fruit, Rybka updates a rough estimate of material balance with weights of 1:3:3:5:10 (in the evaluation this value is then corrected by a delta obtained from the material table)
   Fruit has a 16*16 square mailbox, Rybka has an 8*8
   The programs have different Zobrist hash keys
   The programs have different user interface options

If you are interested is reading this whole article please find below:

Rybka case "greatest injustice perpetrated in computer chess history"

descriptionThe Rybka Case - Greatest Injustice in Computer Chess History EmptyRe: The Rybka Case - Greatest Injustice in Computer Chess History

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VocalTechnique wrote:
The ICGA document neglects to mention a group of chess programmers who did their own investigation with findings that were presented to the ICGA (pre-dating the document). The ICGA then systematically refused to comment on this contra investigation document or its contents.

Unlike the ICGA Rybka investigators (Zach Wegner & Mark Watkins) the contra investigation highlights many important points that Wegner and Watkins missed, such as errors in the reversed engineered material which were deliberately withheld from the documents and deliberately withheld by the ICGA Secretariat from the ICGA investigation Panel.

Whereas the ICGA Rybka investigators could only find 5-7 differences between the evaluation of Fruit and Rybka, the contra investigation shows a long list, in short:

Every major evaluation ingredient is coded differently, mobility, king safety, passed pawns, double pawns, backward pawns, Rybka is missing Fruit's late endgame knowledge, Rybka has a material table – different from Fruit. Rybka does not contain Fruit's quad function, Rybka’s trapped bishop evaluation is different, rook evaluation is different, bishop pair evaluation different and most importantly, Fruit evaluates in stages in a unique way whereas Rybka adds directly to its score (as every other program on the planet does).

Other key differences between Fruit and Rybka:

   Time control is different
   Fen parsing is different
   Rybka extracts the mainline from the transposition table (TT), Fruit via the classic triangle table
   Rybka 1.0 beta displays a mainline of maximum of 10 moves, Fruit produces much longer variations
   Rybka uses a bitboard board representation whereas Fruit is mailbox
   Rybka’s pawn value is 3200 (which is unique), Fruit uses the classic value of 100
   The order in the evaluations of Fruit and Rybka are not similar
   Rybka has lazy evaluation, which is absent in Fruit
   Futility pruning is different between the two programs
   Rybka uses Late Move Reductions (LMR) whereas Fruit uses history reductions
   Fruit uses a history table which is absent Rybka.
   Fruit only has one evaluation table (king safety) while Rybka has many
   The two programs have a different move format
   Rybka does not handle promotions to minor pieces
   The two programs have different hash table code
   They have different handling of repetitions and the 50-move rule in search
   Fruit maintains piece-lists which are not present in Rybka
   Fruit maintains a pseudo "bitboard" for pawns, Rybka has the real thing.
   Contrary to Fruit, Rybka needs to update 4 rotations of occupancy bitboard
   Contrary to Fruit, Rybka updates a rough estimate of material balance with weights of 1:3:3:5:10 (in the evaluation this value is then corrected by a delta obtained from the material table)
   Fruit has a 16*16 square mailbox, Rybka has an 8*8
   The programs have different Zobrist hash keys
   The programs have different user interface options

If you are interested is reading this whole article please find below:

Rybka case "greatest injustice perpetrated in computer chess history"



Very interesting post Vocal

I´ve always had a deep respect for Rybka and I never agreed with all the controversials regarding this pivotal chess engine. Even now after more than 5 years of other engines development, for me,  Rybka is still one of the 3 best engines. Very strong positionally and also when analyzing problem positions. I really hope Vasik Rajlich and his team would launch R5 very soon.

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I will not refer to the shown details, however as I written previously, important is improvment code! Even after  decomilation and theft of code and concepts, important are significant improvements and not just prescribed code with changes to divert attention.
Obviously theft is bad thing but it is sad reality - common progress by thefting ??!! Should be common progress by Open Chess Sotware (Source) like Stockfish ?!

http://rybkaforum.net/cgi-bin/rybkaforum/board_show.pl?bid=23
http://rybkaforum.net/cgi-bin/rybkaforum/board_show.pl?bid=2

Last edited by Kajordzak on Sat Dec 14, 2013 10:00 pm; edited 2 times in total

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@MadMax777 wrote:


[...]Rybka is still one of the 3 best engines. Very strong positionally and also when analyzing problem positions. I really hope Vasik Rajlich and his team would launch R5 very soon.


I agree. In my opinion, Rybka's unequaled strength at that time permanently changed how programmers and enthusiasts view the limits and/or lack of in computer chess as it is today.

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@Kajordzak wrote:

Obviously theft is bad thing but it is sad reality - common progress by thefting ??!! Should be common progress by Open Chess Sotware (Source) like Stockfish ?!


Well, Stockfish chess engine is completely unique compared to it's counterparts, because the code is original to  Stockfish with the exception of the forked code from the Glaurung Project. Houdini author, Robert Houdart, admitted that the Houdini engine incorporates ideas from Stockfish as well as parts of the Ippolit code. My question is, "how much?"

As far as I know, he will not disclose this information to the public. I would like to know if he used all of the  Stockfish and/or Ippolit code and highly modified it or if he developed his own platform from which he added ideas from one or both of the available open sources.

I think I would be more satisfied if he was a little more transparent with the chess community. because what he has created... is extraordinary.

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Yeah, I and others want also to know the secrets of the "kitchen" authors chess programs like Houdini, especially engines! Here, however, is money - it is dreaming of perfection, always partially achieved! To check yourself to make decompilation Houdini source and others ... bigsmile

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Rybka in addition to the penalty may deserve a reward? The allegations concerned to use of Fruit and Crafty, Fruit not developed a long time and both programs have never been at the top of the ranking lists! As I wrote, for the use of the code was a penalty but V.R. developed the ideas and made significant progress in the power play chessengines - and should not reward from ICGA? Maybe rightly too writes about the injustice judgment ICGA ?! I would like to see strong Deep Rybka 5 too !!!

There are no obstacles to each engine gave its source code, of course after securing copyrights of those parts they do not want to share, then you could find the answers to your questions - but it also idealism!

Fruit: http://chessprogramming.wikispaces.com/Fruit

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@Kajordzak wrote:
[...]Fruit not developed a long time and both programs have never been at the top of the ranking lists! As I wrote, for the use of the code was a penalty but V.R. developed the ideas and made significant progress in the power play chessengines - and should not reward from ICGA? Maybe rightly too writes about the injustice judgment ICGA ?! I would like to see strong Deep Rybka 5 too !!!

There are no obstacles to each engine gave its source code, of course after securing copyrights of those parts they do not want to share, then you could find the answers to your questions - but it also idealism!


You make a good point Kajordzak.

In one circle, you could take the stance that the ICGA did as they were intended by bringing to light "cheating by utilizing code from another source into their own program".

For instance, please take a look at the following ICGA rule #2:

> Tournament Rules of the 15th World Computer-Chess Championship

2. Each program must be the original work of the entering developers. Programming teams whose code is derived from or including game-playing code written by others must name all other authors, or the source of such code, in their submission details. Programs which are discovered to be close derivatives of others (e.g., by playing nearly all moves the same), may be declared invalid by the Tournament Director after seeking expert advice. For this purpose a listing of all game-related code running on the system must be available on demand to the Tournament Director.

In another circle, you could take the stance that the any Open-Source code that is not "private" is free for use to utilize and improve upon to create your own entity, even if that entity is for profit. Some could argue that any open source code translates to free code that can be distributed without following the GPL license rules.

Take for instance this -

A "derivative work" is defined in the Copyright Act, 17 USC 101, as a:

"work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a ‘derivative work’."

Simply combining a copyrighted work with another work does not create a derivative work. The original copyrighted work must be modified in some way. The resulting derivative work must itself "represent an original work of authorship." So if the licensee does not modify the original GPL-licensed program, but merely runs it, he is not creating a derivative work."

The question now is finding a way to measure between these two and act accordingly now that we know how they are defined. Finding that fine line can difficult.

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