Fabien's open letter to the community

[Frank Quisinsky]

Hi Tord,

such an answer I search from yourself in the time we made the interview (one of my questions, in the end of the interview).

But now we have it and its wonderful that it's comes from yourself, a programmer with relishes a good call and develops in one work great steps for all of us.

You and Fabien can be a dream team, of course with Marco and Jooni which make a great work in development Stockfish.

For the others:

Interview with Tord Romstad:
http://www.schach-welt.de/interviews/ro ... talba-engl

And an interesting interview (I believe I made it around 2005) with Fabien can be found on Arena webpage. Read this one a bit between the lines.

Best and thanks
Frank

[hgm]

Well this is interesting. Thanks Tord.

It sounds like Fabien believes Rybka has Fruit parts. Possibly a GPL violation. Who is the current copyright owner of Fruit 2.1? At one point I heard it was the FSF, and I'm sure they would be more than happy to go after the non-Free Rybka....

Peter

I don't understand the fuss. What Fabien _believes_ is of zero and void relevance, isn't it? The Strelka code is pubic. The Fruit code is public. Everyone that can read can _see_ if one is derived from the other, and if that is a copyright violation or not. Or is everyoone here a complete dyslectic, all worshippers of Fabien as the only person in this Universe that knows how to read?

[Frank Quisinsky]

Hi Tom,

I am since the story around IPP family not longer a fan of Rybka and the programmer of Rybka too. It's all the time interesting what Bob wrote to this topics.

Today we ought to learn from experience and should not sentenced persons is this experience was painfull.

Vas himself developed great ideas. No other programmer reach the playing strength Rybka has so many years before the IPP family and Stockfish, Houdini come out.

I await a clear statement since more as one year from Vas. Nothing comes. Why? Today such a statement isn't longer interesting because the topic is over.

It's to hard to wrote:
Yes I used Fruit but look what I do ...
No other programmer develops so many years a stronger engine I do.

The leopard can't change his spots!

This wasn't an "sorry" but a clear statement!

I am sure that all programmers used ideas from open sources. Much of the chess engines today are commercial available.

So long we have open sources, normaly no engine can be for sell because if we search we will found a bit.

I don't think that we can say in times today ... GPL is right. Most of the problems in questions open sources / clones / commercial engines comes by GPL. GPL made it complicated!

Error in thinking from GPL programmers!
Error in thinking by commercials ... I can use all what I can find, later if the situation is a bit danger all will be sitting out.

Best
Frank

[Uri Blass]

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.

The information that I can provide is that
Strelka1.8 is designed to be as similiar as possible to rybka1 beta.
There are positions when they have the same fail high and fail low and when I analyze blocked positions I get almost the same data(evaluation may be different by 0.01 pawns or something like that but they have the same fail high and fail low when the only difference is that free source strelka needs to get depth that is bigger by 2 plies).

strelka1.8 and Rybka1 beta even share the same bug that no program that I know has(not a bug that fruit has).

see the change in the evaluation from -6 to -9 and watch the evaluation numbers that are the same.

Rybka
-6.73/3
-6.94/4
-9.00/5
-8.94/6
-9.00/7
-9.00/8

Strelka
-6.73/5
-6.94/6
-9.00/7
-8.94/8
-9.00/9
-9.00/10

Here is the full analysis

[D]rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNB1KBNR w KQkq - 0 1

Analysis by Strelka 1.8 UCI:

1.Ng1-f3
-+ (-6.41) Depth: 1 00:00:00
1.Nb1-c3 Nb8-c6
-+ (-6.97) Depth: 2 00:00:00
1.Nb1-c3 Nb8-c6 2.Ng1-f3
-+ (-6.41) Depth: 3 00:00:00
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6
-+ (-6.97) Depth: 4 00:00:00
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6 3.d2-d3
-+ (-6.73) Depth: 5 00:00:00
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6 3.d2-d3 d7-d5
-+ (-6.94) Depth: 6 00:00:00 3kN
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6 3.d2-d3 d7-d5 4.a2-a4
-+ (-9.00) Depth: 7 00:00:00 18kN
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6 3.d2-d3 d7-d5 4.a2-a4 Nc6-b4
-+ (-8.94) Depth: 8 00:00:00 569kN
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6 3.d2-d3 d7-d5 4.a2-a4 Nc6-b4 5.Ke1-d1
-+ (-9.00) Depth: 9 00:00:01 807kN
1.Nb1-c3 e7-e6 2.Ng1-f3 Ng8-e7 3.d2-d3 Ne7-d5 4.Nc3-b1 Bf8-b4+ 5.Ke1-d1 Nb8-c6 6.Nb1-a3
-+ (-9.00) Depth: 10 00:00:03 3534kN

(, 24.01.2011)

New game - Houdini 1.5 w32
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNB1KBNR w KQkq - 0 1

Analysis by Rybka 1.0 Beta 32-bit:

1.Nb1-c3
-+ (-6.73) Depth: 3 00:00:00
1.Nb1-c3
-+ (-6.94) Depth: 4 00:00:00
1.Nb1-c3 Nb8-c6
-+ (-9.00) Depth: 5 00:00:00
1.Nb1-c3 Nb8-c6 2.Ng1-f3
-+ (-8.94) Depth: 6 00:00:00 163kN
1.Nb1-c3 Nb8-c6 2.Ng1-f3 Ng8-f6
-+ (-9.00) Depth: 7 00:00:00 227kN
1.Nb1-c3 d7-d5 2.e2-e3 Nb8-c6 3.Ng1-f3
-+ (-9.00) Depth: 8 00:00:01 699kN

(, 24.01.2011)

Uri

[Frank Quisinsky]

Hi John,

perhaps you can explain me ...
Why is playchess important?

What is allowed and what not is a ruling by one person, perhaps a little group of persons. In my opinion not an official ruling and from there not important!

I dont give damn shit.

Best
Frank

[Sylwy]

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).

Hi Graham !

Because you are an experienced man;
after "The Declaration of Independence" of Mr.Fabien Letouzey what do you think:
1.Vas will run his cluster - affair from jail/monastery ?
2.The sysops from Playchess.com will become angels ?
3.ChessBase GmbH will be renamed in ChessFruitDerivatives GmbH ?

Thank you a lot in advance !

S

[Sylwy]

Things got ugly. And now, what will happen?

Jail ! Not clear ?
Making money from a GPL & without permission ................................


S

[hgm]

It is really remarkable how everyone tries to twist facts to confirm their own point of view. Are they unable to read, or do they suppose that others are not able to read, so they can get away with posting any nonsense they want?

As a service to the dyslectic, I repeat the qoute of Fabien with some bold-face highlighting of mine:

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.

[JuLieN]

@HGM
Allow me to be a bit parodic, and don't take it bad.

It is really remarkable how everyone tries to twist facts to confirm their own point of view. Are they unable to read, or do they suppose that others are not able to read, so they can get away with posting any nonsense they want?

As a service to the dyslectic, I repeat the qoute of Fabien with some bold-face highlighting of mine:

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.

[Sylwy]

@HGM
Allow me to be a bit parodic, and don't take it bad.

It is really remarkable how everyone tries to twist facts to confirm their own point of view. Are they unable to read, or do they suppose that others are not able to read, so they can get away with posting any nonsense they want?

As a service to the dyslectic, I repeat the qoute of Fabien with some bold-face highlighting of mine:

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.