Fabien's open letter to the community

[Matthias Gemuh]

This means (to me), there is most probably an ethical issue or case "Fruit versus Strelka(1)", but not a legal one between these two. This distinction should be made for precision of discussion. Also, we don't have to assume necessarily that Strelka 2.0(!) is identical in that respect, to any Rybka. But as for the initial, first Strelka and Rybka 1.0 beta, I remember that a couple of identical bugs and/or output (considering depth+2) e.g. in strange positions were posted here. That didn't leave any room for doubt IMO.

Of course, having no direct copy & paste from Fruit into Strelka (considered to be based on re-engineering from a binary) doesn't prove that there is no copy & paste Fruit code in Rybka 1.0. But it also doesn't prove the opposite!

Anyway, if code was not "taken directly" like in copy & paste but rewritten, then I guess there are no legal issues in terms of licenses and/or copyright, but certainly a question of ethics...

"rewritten" ?

Implemented algorithms were "translated" to a bitboard infrastructure.
The translator ends up with a working implementation of an algorithm he may never have been able to code from scratch.
It is "copy and paste" with unavoidable adaptations/translations.

That is how DanChess once cloned Crafty's evaluation, and was condemned in this forum as a clone.

Matthias.

[Gino Figlio]

Well, it looks like I am going to have to delete Rybka 3 and Rybka 4 from my computer. I am not being facetious either.

On principle I have stayed away from the Ipps and Houdini and now to stay principled I am not going to be able to continue using Rybka.

Makes me sad, but that is the way it is.

(it actually makes me a little angry as well since I paid for Rybka...I wonder if I can get my money back?)

I am not sure why you would do something like that. The potential problem is between the real author and the one that stole code. Neither one of them get anything out of your suggested actions.

[tomgdrums]

Well, it looks like I am going to have to delete Rybka 3 and Rybka 4 from my computer. I am not being facetious either.

On principle I have stayed away from the Ipps and Houdini and now to stay principled I am not going to be able to continue using Rybka.

Makes me sad, but that is the way it is.

(it actually makes me a little angry as well since I paid for Rybka...I wonder if I can get my money back?)

I am not sure why you would do something like that. The potential problem is between the real author and the one that stole code. Neither one of them get anything out of your suggested actions.

It has nothing to do with what either author gets or doesn't get from my actions. It is about being consistent in my actions and thoughts. Period.

[Gino Figlio]

Well, it looks like I am going to have to delete Rybka 3 and Rybka 4 from my computer. I am not being facetious either.

On principle I have stayed away from the Ipps and Houdini and now to stay principled I am not going to be able to continue using Rybka.

Makes me sad, but that is the way it is.

(it actually makes me a little angry as well since I paid for Rybka...I wonder if I can get my money back?)

I am not sure why you would do something like that. The potential problem is between the real author and the one that stole code. Neither one of them get anything out of your suggested actions.

It has nothing to do with what either author gets or doesn't get from my actions. It is about being consistent in my actions and thoughts. Period.

It's hard to build consistent thoughts about complex issues in the absence of facts and in such a short amount of time. Congratulations, I could not do that so quickly.

[M ANSARI]

Somehow I feel I understand the post differently than others. It seems like Fabien is "asking" about several allegations and wants to be up to date on what the allegations are ... nothing I read says anything about confirming anything. Hard to believe that Fabien has been oblivious about this controversy, but I guess computer chess is not as important to some as we would like to believe. Also this is also about Strelka, where the author said he patched up some of his code he couldn't decompile by copying Fruit code. I think we should give Fabien some time to see what the allegations are and then either confirm or deny the set of allegations that he saw. Of course his opinion means more than anyone's. I think too much is being made about Rybka 1.0 beta and since that was free, I don't see it as a big deal (although very wrong if a violation did occur). What would be important is to see if the Rybka's that were sold for profit have any violations ... so maybe the first commercial Rybka should be looked at and scrutinized rather than the free beta. There is a huge difference between a free closed source program that might have violated a GPL license, and a program that goes commercial by simply copying existing code and modifying some parts. Maybe someone could get Fabien up to speed and show him Zack's report and maybe BB's report on Ippolit, and some other stuff that has been shown as proof of violations. I would be very interested in what he has to say about that.

[Dr.Wael Deeb]

First thing came to my thoughts after reading the article is a huge lie Vasik was spreading through all these years....that he,Vasik,contacted Fabien regarding the fruit-Rybka affair and Fabien is fine with it and even doesn't care which as I wrote turned out to be a huge lie....
Dr.D

[Graham Banks]

Somehow I feel I understand the post differently than others. It seems like Fabien is "asking" about several allegations and wants to be up to date on what the allegations are ... nothing I read says anything about confirming anything..........

This is also how I see it at this stage.
Fabien is asking for further information and will then need time to study what is required before he can make some definitive statements on the issue.
I think it's great that Fabien has chosen to get involved and I sincerely hope that Vas will have his say too (if required).

[Ovyron]

It's going to be a difficult case, Vas never saved his sources codes, he doesn't have the Rybka 3 one, so I'm sure he doesn't have the code of Rybka 1.1 or 2.0, all the investigations would need to be done as reverse engineered code.

It was unfortunate that Vas claimed Strelka's code as his own, since later it was found out that it had significant parts of Fruit.

As about the ply and node count obfuscations, they have been explained at Rybka forum, 3 plies are added to normalize the count relative to other engines, as earlier plies are "thinner" and don't fulfill their definition of ply, nodes are recalculated so they can be used to compare different hardware, i.e. higher nodes must mean higher strength at all times, unlike other engines that with hyperthreading show higher node count but play weaker.

[Frank Quisinsky]

Graham,



The result of your time for study will be not important Graham. Not more important as the study from all others in using chess engines. This one you have to learn, we all have to learn too.

So, you will be the biggest IvanHoe fan the World will see. I wrote this to you more as one times.

Yes Graham, the World is broken ...
For so many computer chess fans ... not for you alone.

But this one must not be the end.
More or less the computer chess chronicle will start now with the year 0. I think the first step to make so many things better ...

Yes, time to start with 0.
The evolution after the questions of compatibilities with engine protocols started now!

And I hope with Fabien and much others with gave us the important basic approachs and be able to develops new "open" ideas.

A lot of real persons which working for this hobby are more or less in background activ. Persons which try to stand in the foreground should be more questioned.

And persons which try to rule have other things in his brain. It's not only money! More acknowledgement / acceptance. Can't understand such things because the community isn't big enough "at the moment".

Best
Frank

[De Vos W]

Somehow I feel I understand the post differently than others. It seems like Fabien is "asking" about several allegations and wants to be up to date on what the allegations are ... nothing I read says anything about confirming anything..........

This is also how I see it at this stage.
Fabien is asking for further information and will then need time to study what is required before he can make some definitive statements on the issue.
I think it's great that Fabien has chosen to get involved and I sincerely hope that Vas will have his say too (if required).

If Strelka is Fruit says Fabien Letouzey and Strelka is Rybka says Vasik Rajlich, isn't this saying that Rybka is Fruit ?

http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=3006


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By Vasik Rajlich Date 2008-01-11 12:26

I've taken a look this morning at the Strelka 2.0 sources.
The picture is quite clear.
Vast sections of these sources started their life as a decompiled Rybka 1.0. The traces of this are everywhere. The board

representation is identical, and all sorts of absolutely unique Rybka code methods, bitboard tricks and even exact data tables are used

throughout. Significant portions of the search and evaluation logic are not fully disassembled - the author has left in hardcoded

constants and used generic names (such as "PawnStruScore0" & "PawnStruScore1", "PassedPawnValue0" through

"PassedPawnValue7", etc) which show that he hasn't yet fully understood what is happening.

In some cases, these traces do also extend beyond the inner search and evaluation kernel. For instance, Rybka and Strelka are the

only engines which I know about which don't report "seldepth" and "hashfull". Rybka's UCI strings are used throughout.

The author did at first make attempts to hide the Rybka origins, for example by masking the table values in earlier Strelka versions. He

also made significant attempts to improve the program. The attempts at improvement are not very original, but they are everywhere.

They include PV collection, null verification (and in fact changes to the null implementation itself), some endgame drawishness

heuristics, a handful of new evaluation term, a new approach to blending between opening and endgame eval terms, and so on. They

also do include various structural changes, such as knight underpromotions, on-the-fly calculations of many tables, the setting of

piece-square table values, etc. These changes are extensive and no doubt lead to differences in playing style and perhaps a useful

engine for users to have, but they do not change the illegality of the code base.

In light of the above, I am claiming Strelka 2.0 as my own and will release it in the next few days under my own name. The name of the

author with the pen name "Osipov" will be included if he comes forward with hiw own real name, otherwise an anonymous contribution

will be noted. The contributions of Igor Korshunov will also be confirmed and noted if appropriate. All usage permissions will be granted

with this release.

I do not see obvious signs of other code usage, but perhaps this deserves a closer look. Some of the transplanted ideas, such as the

null verification search, are rather naive implementations of the approach in Fruit/Toga, although my first impression is that that code

itself is original. The Winboard parser from Beowolf which was added to Strelka 1.0 seems to have been completely removed. If

someone else does find other signs of code theft, please get in touch with me and I will give proper credit in the upcoming release.

If someone has suggestions about an appropriate license, and in particular the pros and cons of the GPL for a chess engine and for this

unusual scenario, or if someone would be willing to help in preparing this code and license for release, please also get in touch with

me.

As this code is two years and several hundred Elo old, I am not going to launch any major action. However, 'Osipov' has already

threatened to repeat the procedure with Rybka 2.3.2a. (He did this after I declined to grant him rights to commercialize Strelka.) If this

situation does repeat with a newer Rybka version, I will not just stand and watch any more. In the meantime, if someone has information

about 'Osipov', please get in touch with me.