Fabien's open letter to the community

[slobo]

When a new version of a program is being developed, a programer never works with the previous version original: he uses a previous version copy. Of course, I mean a programer with normal inteligence.

[Jeremy Bernstein]

When a new version of a program is being developed, a programer never works with the previous version original: he uses a previous version copy. Of course, I mean a programer with normal inteligence.

http://stackoverflow.com/questions/1325 ... on-control

jb

[Matthias Gemuh]

Fabien is now posting personally in CCC .

[Prima]

Fabien is now posting personally in CCC .

You beat me to the punch, Mathias . Fabien could not post due to account activation-period. Indeed, Fabien Letouzy is now able to post directly in CCC forum http://talkchess.com/forum/viewtopic.ph ... 99&t=37762

To all experts, here's that chance to get the truth openly, since Vas would not say anything or admit to anything despite the facts proving the obvious: all Rybkas are derived from & related to Fruit. Personally, I've always believed the words of computer/programming experts and "code analyser etc" as facts and the truth in the case of Fruit-Strelka-Rybka and Rybka's general origins.

Hearing these facts (whatever these facts may be) openly confirmed by Mr. Fabien Letouzy will settle the case once and for all. The so-call "moral/ethical troops" who 'happen' to be Rybka-fan boys/Chessbase Sysops/Certain forum moderatos seem to be awfully silent now - a big 180 degree-turn from their usual "sureness" and censorship/banning or people with regards to the origins and legitimacy of Rybka. To the point they even ban IvanHoe/RobboLito/FireBird, and now Houdini, from playchess and tournaments, without facts.

[Prima]

Just what Dr. Rober (Bob) Hyatt and other reputable computer/programmers have been saying for years and now confirmed by Mr. Fabien Letouzy
http://talkchess.com/forum/viewtopic.ph ... 31&t=37762
http://talkchess.com/forum/viewtopic.ph ... 56&t=37762

[Harvey Williamson]

The so-call "moral/ethical troops" who 'happen' to be Rybka-fan boys/Chessbase Sysops/Certain forum moderatos seem to be awfully silent now - a big 180 degree-turn from their usual "sureness" and censorship/banning or people with regards to the origins and legitimacy of Rybka.

Please point to any post where I have ever appeared to be a Rybka fanboy?
(bold lettering in quote by me)

[Terry McCracken]

The whole Strelka/Rybka thread is: http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=3006

Here is the principal message from VR (emphasis added):

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.

In the end, he realised that this release plan was infeasible (see the rest of that thread).

I've been censored at the Rybka Forum due to the information that has come to light.

I expect I'll be banned from there.

I've passed this information to ChessBase as well.

[Kevin Frayer]

The so-call "moral/ethical troops" who 'happen' to be Rybka-fan boys/Chessbase Sysops/Certain forum moderatos seem to be awfully silent now - a big 180 degree-turn from their usual "sureness" and censorship/banning or people with regards to the origins and legitimacy of Rybka.

Please point to any post where I have ever appeared to be a Rybka fanboy?
(bold lettering in quote by me)

Of course you have been a Rybka fanboy. You and your cohorts jealously defended this engines validity and its authors allegations that other people were stealing his code. You have used Banning and censorship to effectively silence opposition to what turned out to be unfounded claims.

You Sir, have forfeited your one line in the book of computer chess history.

[Terry McCracken]

My good friend Fabien Letouzey, author of Fruit, asked me to post the following message for him:

Hello,

Long time no see.

First, I am not back to computer chess, sorry about that. I just want to clarify a few things. Sorry if that's old but there is some misunderstanding I need to fix, and I found out only yesterday. Bear in mind that I am mostly unaware of what has happened for five years though.

First there was the Strelka case. Dann approached me with some "Strelka" source code for me to check. I had never heard of it. I assumed it was some closed-source free engine and that people wanted to know whether it was based on the Fruit source code.

The short answer was "no", it was not a verbatim copy of the source code. All the code had been typed (can't say "designed" though, see below) by an individual. So legally there was no issue that I knew of. It was however a whole re-write (copy with different words if you like, similar to a translation) of the algorithms. Not just an extraction of a couple of ideas as is common, and normal.

That being said, some original changes and ideas were also included in the program. So it was, as has since been stated many times in fora I suppose, a bitboard re-write of Fruit with some personal (or otherwise) ideas. Also note that the source code Dann sent me might not be the from the 2.0 version.

Edit: I've just had a look at the 2.0 sources. On top of what I said above, there are many constant and function names that are identical to Fruit's. I remember noticing it back then as well.

Hope it helps, because my email answer to Dann was unusually short and cryptic even by my standards. And Dann, please next time make it clear when you want a public statement instead of a private opinion, thanks.

I want to point out something immediately: there was no mention of Rybka whatsoever. Indeed I was unaware of any relation between Strelka and Rybka, this is precisely what I learned only yesterday. I insist because it seems I have often been quoted about "not caring" about the (possible) Fruit/Rybka relationship, but this is not so. Strelka did not look like a problem because I assumed it was free.

Next, I was approached by Ryan (I think) and Christophe Theron about whether I could help with some "possible Fruit code inside Rybka" issues. I answered "yes, but how?", but did not get a reply. This did not make me really aware of a clone possibility however because I thought they were talking about some insignificant UCI-handling code or whatnot. Also this was several years after the initial Rybka release, and I guess quite a few people had a close look at it. Apparently Chrilly did?

Now if someone could tell me a bit more about the major events last five years and the current state of affairs, I'd be much obliged.

A few things I noticed yesterday, can you confirm?
- Rybka search info was obfuscated in some way (like displaying depth-3 or something), any pointers on details please?
- Vasik claimed that Strelka 2.0 is a clone of Rybka 1.0 (and you know what that would imply!)
- Zach Wegner found many Fruit ideas (and nearly identical code) in Rybka 1.0; I think someone else did, too
- Some even stronger open-source program appeared as a decompilation of Rybka (with own ideas, sounds familiar), what came up of looking at those?

Any questions, now is the one time to ask.

Thanks for your attention,

Fabien Letouzey.

I've been censored at the Rybka Forum due to the information that has come to light.

I expect I'll be banned from there.

I've passed this information to ChessBase as well.

Terry McCracken


Sorry, I meant to reply to Tord's initial post.

[Harvey Williamson]

The so-call "moral/ethical troops" who 'happen' to be Rybka-fan boys/Chessbase Sysops/Certain forum moderatos seem to be awfully silent now - a big 180 degree-turn from their usual "sureness" and censorship/banning or people with regards to the origins and legitimacy of Rybka.

Please point to any post where I have ever appeared to be a Rybka fanboy?
(bold lettering in quote by me)

Of course you have been a Rybka fanboy. You and your cohorts jealously defended this engines validity and its authors allegations that other people were stealing his code. You have used Banning and censorship to effectively silence opposition to what turned out to be unfounded claims.

You Sir, have forfeited your one line in the book of computer chess history.

You are wrong. There are several posts out there where I have been critical. Wait till the Mexico story is published when I write my book. To be honest I do not care what you think this is enough for me http://www.hiarcs.com/media/anand.wav Who needs the Rybka Cluster