Rybka 1.0 vs. Strelka

[bob]

Hi Chris,

[snip]

Fabien says he has no problem.

Where did Fabien say it? This is of key importance in the whole issue.

Enrique

It's a bit convoluted, but the argument of the "Rybka 1.0 beta might be a clone camp" goes like this ...

Strelka is a reproduction of Rybka 1.0 beta.
Strelka resembles Fruit at a programming level
Therefore Rybka 1.0 resembles Fruit.

The "Rybka 1.0 beta protection society" argues:
Fabian has no worries with Strelka.
If other side wants to argue Strelka = Fruit
then Fabian by extension also has no problems with Rybka.


Bob wrote:
Didn't Vas clearly post "Strelka is a reproduction of Rybka 1.0 and I am claiming it as my own code now"??? I saw that specific comment (probably not those exact words, but semantically _identical_ posted by him when the Strelka / clone issue first broke.

Dan Corbit wrote:
This is what Fabian said about Strelka:
"No worries as far as I am concerned.
Ideas are not a legal property.
The code was rewritten so it's OK with me.
Tournament organisers might think differently.
I cannot say a definite yes or no ..."

Some programmers found code similarities between Strelka and Fruit; Vasik said that Strelka was R1 beta; Fabien told Corbit that he didn’t mind about Strelka. When was all that?

I’m asking because I would like to know why these accusations take place now and not in the old times of Rybka 1 beta. And whether they are related to other accusations here last week about Rybka giving R2 for free and not showing the true node count. I’m not saying it’s a campaign, but it might very well look like it, with these three simultaneous accusations against Rybka just before China 2008 and immediately after the huge lead of Rybka 3.

By the way, when Vasik said that Strelka was R1 beta, was he referring to the whole program or to parts of it? If to parts of it, the whole accusing syllogism (part of Str = Fr, part of Ry = Str, therefore Ry = Fr) is false, because Strelka could have copied parts of Rybka code different than Fruit. Possible? I'm asking you as programmer. I'm lay.

As for your "Tournament organizers might think differently", Rybka 3.x will play in China, not R1 beta, so I don’t see on which grounds the organizers could object.

Enrique

It is not much of a stretch to believe that R2 has much of the same source as R1. And that R3 has much of the same source as R2. So _if_ R1 is a partial or complete copy of fruit, R1 is automatically GPL code. And unless R2 was 100% rewritten, R2 would also be GPL. Ditto for R3.

So we end up with a direct connection from fruit -> strelka -> rybka 1, with the probable connection of Rybka 1 -> Rybka 2 -> Rybka 3.

I have not been involved in discovering this, I have followed the discussions, and have stated several times that based on the evidence that has been presented, things appear to be a bit off-color. Since the Rybka group are offering no arguments or evidence to the contrary, it would be hard to draw any other conclusion.

You say "_if_" above, and then go on to "probable connection".

Methinks you should be extremely cautious before alleging a connection between R1->R2->R3 and then asserting a problem with R1.

Do you have evidence that R3 has R1 beta code contained within? If not, the comments above are exceptionally dangerous.

Did you read what I wrote? I wrote (and rewrote) "blitz" 7 times. _major_ changes. But big chunks of code were reused. Who needs a new opening book format, new PGN parser, new move input/output code, etc? I then rewrote Cray Blitz three times. Major changes. 20,000 lines of assembly language added. over a Period of several years. Yet each had at least 60% of code re-used. I have rewritten Crafty 3-4 times as it was time to clean up and re-do. And again, 50+ % (if not more) of the code was kept. The most recent rewrite where I eliminated all duplicate code was a big change, but tons of reuse.

I wrote above "It is not much of a stretch to believe that most of R1 source was retained and used in R2, and that most of R2 would be reused in creating R3." I see _zero_ danger there and if someone would want to challenge me on it, suits me. The university has a team of lawyers to handle such nonsense. I did not say "absolutely, R3 contains part of R1". I said "it most likely does" and I'd stake my software engineering reputation on such a statement any day of the week... The probability is _HIGH_ that if R1 contains GPL code, R2 and R3 also do. But even if not, if R1 contains GPL code, that could be a significant legal issue for someone if the FSF folks get interested.

_If_ R1 beta contained GPL code then the probability that R3, a commercial release through a publisher, contains any of that code is extremely low, not high. The simplistic assumption via the naming does not apply.

If you believe that, fine. Personally, I don't rewrite code that is working, that is functional, and that does exactly what is needed. I rewrite the parts that are being improved. That is a basic tenet of every software engineering book on the planet, AKA "code reuse". It is _the_ reason languages like C++ were developed, to make reuse even easier.

[bob]

Hi Chris,

[snip]

Fabien says he has no problem.

Where did Fabien say it? This is of key importance in the whole issue.

Enrique

It's a bit convoluted, but the argument of the "Rybka 1.0 beta might be a clone camp" goes like this ...

Strelka is a reproduction of Rybka 1.0 beta.
Strelka resembles Fruit at a programming level
Therefore Rybka 1.0 resembles Fruit.

The "Rybka 1.0 beta protection society" argues:
Fabian has no worries with Strelka.
If other side wants to argue Strelka = Fruit
then Fabian by extension also has no problems with Rybka.


Bob wrote:
Didn't Vas clearly post "Strelka is a reproduction of Rybka 1.0 and I am claiming it as my own code now"??? I saw that specific comment (probably not those exact words, but semantically _identical_ posted by him when the Strelka / clone issue first broke.

Dan Corbit wrote:
This is what Fabian said about Strelka:
"No worries as far as I am concerned.
Ideas are not a legal property.
The code was rewritten so it's OK with me.
Tournament organisers might think differently.
I cannot say a definite yes or no ..."

Some programmers found code similarities between Strelka and Fruit; Vasik said that Strelka was R1 beta; Fabien told Corbit that he didn’t mind about Strelka. When was all that?

I’m asking because I would like to know why these accusations take place now and not in the old times of Rybka 1 beta. And whether they are related to other accusations here last week about Rybka giving R2 for free and not showing the true node count. I’m not saying it’s a campaign, but it might very well look like it, with these three simultaneous accusations against Rybka just before China 2008 and immediately after the huge lead of Rybka 3.

By the way, when Vasik said that Strelka was R1 beta, was he referring to the whole program or to parts of it? If to parts of it, the whole accusing syllogism (part of Str = Fr, part of Ry = Str, therefore Ry = Fr) is false, because Strelka could have copied parts of Rybka code different than Fruit. Possible? I'm asking you as programmer. I'm lay.

As for your "Tournament organizers might think differently", Rybka 3.x will play in China, not R1 beta, so I don’t see on which grounds the organizers could object.

Enrique

OK, last point first. If you find the first crafty version available, which would now be over 10 years old since it was released in 1995 somewhere, and if you take today's source and diff them. You would find far more than 50% of the code is duplicated. yes the eval has changes. Yes _parts_ of the search has changed. And yes, parts of the move generator have changed. But, if I had "borrowed" that original version of Crafty from someone else, and it had been GPL'ed when I borrowed it, today's version of Crafty would be an illegal copy. The GPL is specific, once you start with GPL code, your code is GPL until _every last line_ has been rewritten so that not one single line of GPL code remains. It is not much of a stretch to believe that R2 has much of the same source as R1. And that R3 has much of the same source as R2. So _if_ R1 is a partial or complete copy of fruit, R1 is automatically GPL code. And unless R2 was 100% rewritten, R2 would also be GPL. Ditto for R3.

Guesswork. Many "would", "if", "unless", "believe" in your writing above. Tournament organizers cannot base any decisions on guesswork, educated or not. Reverse engineer R3 and prove that GPL code from the non commercial R1 beta still exists in Rybka 3. The rest is mere assumption, and one doesn't accuse based on assumptions.

Enrique

The case against R1 looks pretty convincing based on duplicate code that has actually been published with no ifs, ands or buts or "thinks" associated. That looks to be bad, IMHO. I suppose someone will, sooner or later, apply the same reverse-engineering to R2 and R3, to see what they find out.

However, the assumptions being discussed here are very solidly founded in software engineering practices. As far as tournaments go, my policy would be quite simple there. If someone clones a program and enters it as their own work, and then it is proven that the code was a copy/clone of another program, then they are banned from competition for life. If the case against R1 is proven, R2 and R3 become moot as far as I am concerned...

"fool me once, shame on you, fool me twice, shame on me..." comes to mind.

Next, (and by the way, I didn't point out the claim by Vas, CT quoted it and suddenly a "warning light" started blinking as I had just not given this much thought) we do not have the source of R1. But we have a direct statement by Vas that Strelka was a copy of R1, that the source for Strelka was written by reverse-engineering the assembly language in the Rybka 1 executable. And he then claimed that "strelka is my code, and I will now distribute it as such." So we have a direct tie from strelka to Rybka.

Finally, a few have started to compare strelka to fruit, and have found marked similarities, and lots of identical code that is shared between both. So this establishes a link from strelka to fruit.

So we end up with a direct connection from fruit -> strelka -> rybka 1, with the probable connection of Rybka 1 -> Rybka 2 -> Rybka 3.

And all of that is, to me, troubling. Programs are supposed to be original works Not modified copies. Otherwise things I (and others) have complained about in the past suddenly become moot. I can think of Gunda 1 Jakarta, then Le Petite, Voyager, bionic impact and others that I have forgotten about, but all of which were direct copies of Crafty, and all of which created a lot of discussion and all of which were ultimately declared clones, not allowed into tournaments, etc. With that past history, plus others trying to clone programs dating as far back as Chess Genius, it looks to be problematic. And now we have yet another potential derivative work rather than original work.

I have not been involved in discovering this, I have followed the discussions, and have stated several times that based on the evidence that has been presented, things appear to be a bit off-color. Since the Rybka group are offering no arguments or evidence to the contrary, it would be hard to draw any other conclusion.

That is where things stand, and how they have reached the current point. For the people that have been absolutely caught red-handed, I consider them to be the lowest form of morally-challenged con artists. The current case has not yet reached that point. But it is moving in that direction until something convincing shows up to counter the current mountain of evidence. It would be nice to have a "counter-point" here and there that is factual. 90% of the comments are nonsensical and useless for helping to resolve this.

[chrisw]

Hi Chris,

[snip]

Fabien says he has no problem.

Where did Fabien say it? This is of key importance in the whole issue.

Enrique

It's a bit convoluted, but the argument of the "Rybka 1.0 beta might be a clone camp" goes like this ...

Strelka is a reproduction of Rybka 1.0 beta.
Strelka resembles Fruit at a programming level
Therefore Rybka 1.0 resembles Fruit.

The "Rybka 1.0 beta protection society" argues:
Fabian has no worries with Strelka.
If other side wants to argue Strelka = Fruit
then Fabian by extension also has no problems with Rybka.


Bob wrote:
Didn't Vas clearly post "Strelka is a reproduction of Rybka 1.0 and I am claiming it as my own code now"??? I saw that specific comment (probably not those exact words, but semantically _identical_ posted by him when the Strelka / clone issue first broke.

Dan Corbit wrote:
This is what Fabian said about Strelka:
"No worries as far as I am concerned.
Ideas are not a legal property.
The code was rewritten so it's OK with me.
Tournament organisers might think differently.
I cannot say a definite yes or no ..."

Some programmers found code similarities between Strelka and Fruit; Vasik said that Strelka was R1 beta; Fabien told Corbit that he didn’t mind about Strelka. When was all that?

I’m asking because I would like to know why these accusations take place now and not in the old times of Rybka 1 beta. And whether they are related to other accusations here last week about Rybka giving R2 for free and not showing the true node count. I’m not saying it’s a campaign, but it might very well look like it, with these three simultaneous accusations against Rybka just before China 2008 and immediately after the huge lead of Rybka 3.

By the way, when Vasik said that Strelka was R1 beta, was he referring to the whole program or to parts of it? If to parts of it, the whole accusing syllogism (part of Str = Fr, part of Ry = Str, therefore Ry = Fr) is false, because Strelka could have copied parts of Rybka code different than Fruit. Possible? I'm asking you as programmer. I'm lay.

As for your "Tournament organizers might think differently", Rybka 3.x will play in China, not R1 beta, so I don’t see on which grounds the organizers could object.

Enrique

It is not much of a stretch to believe that R2 has much of the same source as R1. And that R3 has much of the same source as R2. So _if_ R1 is a partial or complete copy of fruit, R1 is automatically GPL code. And unless R2 was 100% rewritten, R2 would also be GPL. Ditto for R3.

So we end up with a direct connection from fruit -> strelka -> rybka 1, with the probable connection of Rybka 1 -> Rybka 2 -> Rybka 3.

I have not been involved in discovering this, I have followed the discussions, and have stated several times that based on the evidence that has been presented, things appear to be a bit off-color. Since the Rybka group are offering no arguments or evidence to the contrary, it would be hard to draw any other conclusion.

You say "_if_" above, and then go on to "probable connection".

Methinks you should be extremely cautious before alleging a connection between R1->R2->R3 and then asserting a problem with R1.

Do you have evidence that R3 has R1 beta code contained within? If not, the comments above are exceptionally dangerous.

Did you read what I wrote? I wrote (and rewrote) "blitz" 7 times. _major_ changes. But big chunks of code were reused. Who needs a new opening book format, new PGN parser, new move input/output code, etc? I then rewrote Cray Blitz three times. Major changes. 20,000 lines of assembly language added. over a Period of several years. Yet each had at least 60% of code re-used. I have rewritten Crafty 3-4 times as it was time to clean up and re-do. And again, 50+ % (if not more) of the code was kept. The most recent rewrite where I eliminated all duplicate code was a big change, but tons of reuse.

I wrote above "It is not much of a stretch to believe that most of R1 source was retained and used in R2, and that most of R2 would be reused in creating R3." I see _zero_ danger there and if someone would want to challenge me on it, suits me. The university has a team of lawyers to handle such nonsense. I did not say "absolutely, R3 contains part of R1". I said "it most likely does" and I'd stake my software engineering reputation on such a statement any day of the week... The probability is _HIGH_ that if R1 contains GPL code, R2 and R3 also do. But even if not, if R1 contains GPL code, that could be a significant legal issue for someone if the FSF folks get interested.

_If_ R1 beta contained GPL code then the probability that R3, a commercial release through a publisher, contains any of that code is extremely low, not high. The simplistic assumption via the naming does not apply.

If you believe that, fine. Personally, I don't rewrite code that is working, that is functional, and that does exactly what is needed. I rewrite the parts that are being improved. That is a basic tenet of every software engineering book on the planet, AKA "code reuse". It is _the_ reason languages like C++ were developed, to make reuse even easier.

What you would do is not relevent. You are not commercial. Commercial software has to be clean without danger of challenge. A company with shareholders will be hit by a double whammy if it asserts it owns or licences assets which it knows are of dubious legality. Whammy one - get sued by the real owner. Whammy two - get sued by the shareholders for
not informing them, not putting aside money in the accounts for the risk, and positing untrue asset value statements.

No commercial company with half a brain will publish software claiming total rights over it if not true. That's the overpowering evidence one that R3 is clean. Chessbase won't licence it unless absolutely certain it's clean. That's overpowering evidence two. Say anything else and you play with fire. imo.

[Enir]

You are assuming too much. For example, would you file suit against someone that was making a claim that hurt you, if you_knew_ that the claim was true? Because to file the suit, you have to make a sworn statement that the claim is false in order to seek damages. And if the claim is later proven true, you just committed perjury and are now looking at prison time rather than seeking financial redress from someone else. The sword of justice cuts both ways so caution is required.

I could cut out the other stuff because this here already shows your bias. You simply argue always from the position that Vas has done something wrong. I already wrote a message to write my astonishment how experts could be biased. If you at least would find arguments in favor of Vas, just out of principle. Or also in case you knew how something might have no legal relevance.

Has Vas responded in any way about this? How can one find points in his favor if there is nothing but a deafening silence from his side of the table???

I think he can rely on a purely psychological standpoint for the moment. When did you talk to a commercial programmer collegue during the last 50 years? Now that's going too far. You are looking upon everything like the guy with a hammer. Everything looks to him like a nail while hidden nails frighten him. A commercial programmer cannot discuss what he does, Bob, he lets his program speak. He's in chess what you are on ICC in Bullet. Simply the best!

Sorry, but that boat won't float. When I was accused of cheating several years ago, about something that happened back in 1986. I chose to not sit idly by and let the accusations reverberate around r.g.c.c... I replied factually, quoted a specific letter from David Levy which described the investigation he did and the conclusion that absolutely nothing wrong was done, and so forth. It would be easy enough to simply post "Rybka is my own unique work, I didn't borrow any code form any GPL or open-source programs, so I don't know why this kind of discussion has come up." I can think of only one reason why _I_ would not write that were the discussion about me, I'll leave discovering that reason as an exercise for the reader. I think it is obvious enough that anyone will "get it."

Maybe so. Maybe not. CCC is not ICGA and no one has the obligation, moral or not, to defend from accusations on a forum. It is also possible to look down to them and tell oneself "they bark, so I ride". 2001: been there, done that.

Several people in the last days implicitly accused Vas of copyright breaching. Implicitly. I still have to see an open, unambiguous accusation like "Vas copied Fruit, is a plagiarist and breached Fabien's copyright." Maybe Vas is waiting for this?

Enrique

Hi Enrique

Such a statement would be deleted by the moderators.

Olivier

Hi Olivier,

I don't think it would be deleted, provided it were backed up by evidence. But better ask the moderators about it.

Instead, please notice all those "if", "imo", "would", "seem", etc. You don't pass judgemnent based on that.

This is not CTF, but it may be interesting to notice that plagiarism was perfectly common and accepted until not so long ago, when every single piece of private production became sacred. For instance, many Bach harpsichord concerti are just a transcription of Vivaldi works for the violin, note by note. Had Vivaldi put his scores under GPL, oh my god...! I don't mean by this that we should condone Bach’s mischief, of course.

Enrique

[Olivier Deville]

Enrique, please check this :

http://www.open-aurec.com/wbforum/viewtopic.php?t=49365

Olivier

[Enir]

Enrique, please check this :

http://www.open-aurec.com/wbforum/viewtopic.php?t=49365

Olivier

That's why the tiptoeing? I can't believe it. All sort of things are being insinuated, claimed, and that thread is becoming huge. But, as I said before, moderators could enlighten us about whether or not that sentence would have been deleted by them.

Enrique

[chrisw]

Enrique, please check this :

http://www.open-aurec.com/wbforum/viewtopic.php?t=49365

Olivier

That's why the tiptoeing? I can't believe it. All sort of things are being insinuated, claimed, and that thread is becoming huge. But, as I said before, moderators could enlighten us about whether or not that sentence would have been deleted by them.

Enrique

Enrique,

Olivier is stretching facts. There was a thread posted by Olivier deleted some time ago. The thread title was "program XYZ by programmer ABC is a clone". No doubt in that title. That thread grew in short time to seven posts long with no supporting data presented at all. There were some assertions by Conkie but no data. The thread was deleted and Olivier sent a polite PM saying he was welcome to repost in the form of a discussion but without making direct accusations (like the thread title for example). Olivier didn't repost.

Re a direct accusation of the type you quote ....

I spoke to Vas at the start of these threads. His attitude is that discussion is surely ok. He thinks it should be ok as long as the forum has some sort of ground rules and the debate is balanced. This is my position also.

Direct accusations at this stage would be without sufficient support evidence built up so far, in my view. They would therefore be against forum ground rules, which are "discussion is fine, libel is not".

Chris

[Olivier Deville]

Well, Rolf has been using this style of language now since 1995. He's an old papal edifice of computer chess forums and he does, certainly in this case, provide an important balance of argument. Rolf uses a kind-of psycho-intuition on topics, sometimes he gets it right and sometimes wrong - the language is a kind-of provocative probe into the viewpoints of the other side which sometimes bears fruit, sometimes not. There is a fine line of course between provocative probing and mud-slinging and moderators have the unenviable task of trying to distinguish between the two, not helped by differences in general opinion of the moderators themselves. Or you could see it all as part of life's rich tapestry, maybe?

What are you suggesting actually? His posts are edited? Deleted? Or? I mean gimme some advice here

How about warnings, followed by strikes, followed by sanctions for continued abuse? In his case, all he does is spew OT gibberish. There's no need to edit his posts, or delete them. That makes it impossible to illustrate to him and everyone else what the problem is.

Threads that go haywire can be locked. Again, why censor? Just lock the thread after replying to it with information about why it was locked. It will die quickly. If someone reopens the mess, you can issue sanctions.

I'd say censor by editing a post, and only in specific circumstances:
1) bad words. replace them with [*edited for content -mod]
2) gratuitous advertising. again, replace with [*removed advertising -mod]

Not much else should be censored. If something is against the charter, just point it out, and give warnings. But leave it intact, otherwise nobody ever has a clue what the problem is, and it will happen over and over. Again, you can always lock a thread that goes out of control.

Very wise policy Bob.

Be a candidate for next mod elections and I'll vote for you.

Olivier

[bob]

I think the thing that worries me the most here is that this dicussion would give _anyone_ serious doubts about the functionality of a trial-by-jury system. You'd think that everyone would look at the evidence _first_ and then form an opinion. Not so here. The evidence is not even considered. Hopefully none that operate like that get called for jury duty, otherwise the criminal justice system will be about anything _but_ justice.

The current discussion is hinging on the thread from Rybka 1 beta obviously being similar to Strelka (Vas' words) and Strelka being nearly identical with Fruit. That evidence is overwhelming. So now several with significant experience in chess program development (as well as operating system development, compiler development, etc) suggest that Rybka-1 beta to Rybka 1almost certainly included borrowing most of the beta code for the final release, and then that Rybka 2 almost certainly contains much code from Rybka 1, and ditto for version 3 with respect to version 2. And we are hung up in never-never land where a beta version gets _completely_ rewritten before release. That's hardly the definition of "beta release" in any usage I have seen. I think we are more likely talking about "rapid prototyping" where one might use the framework of an existing program so that just key parts could be written to use in a "proof of concept test". But this is often done in a language like Visual Basic or other "drag and drop" developmental environment, where production code uses something that performs significantly better.

I find the current similarity between Strelka/Rybka and Fruit to be quite surprising. And the conclusions put forth by others are pretty compelling in light of the published evidence. I'd be more than willing to listen to any offered explanation from the primary group responsible. But this nonsense about complete rewrites and such is just that, nonsense. Yes, an author generally is required to execute a "claim of ownership" statement, but no company will go to the ends of the earth to verify the claim, they just make it clear in the agreement that any legal troubles that arise will be the responsibility of the author, not the company.

Perhaps, at some point, the Rybka team will address some of this. With factual statements. But the statements have to stand up to a factual verification, since I am sure someone is waiting in the wings with disassembled Rybka 2 code, so claiming the beta was completely rewritten before version 1 was released can be verified with some work.

But so far we are getting little from one side, and a mound of data from the other. I'm not interested in Rybka in the least, I have my own program to worry about. But I can certainly look at what has been presented and think "Hmmm..." If it doesn't make you think for a bit, then you obviously are not impartial.

[bob]

Hi Chris,

[snip]

Fabien says he has no problem.

Where did Fabien say it? This is of key importance in the whole issue.

Enrique

It's a bit convoluted, but the argument of the "Rybka 1.0 beta might be a clone camp" goes like this ...

Strelka is a reproduction of Rybka 1.0 beta.
Strelka resembles Fruit at a programming level
Therefore Rybka 1.0 resembles Fruit.

The "Rybka 1.0 beta protection society" argues:
Fabian has no worries with Strelka.
If other side wants to argue Strelka = Fruit
then Fabian by extension also has no problems with Rybka.


Bob wrote:
Didn't Vas clearly post "Strelka is a reproduction of Rybka 1.0 and I am claiming it as my own code now"??? I saw that specific comment (probably not those exact words, but semantically _identical_ posted by him when the Strelka / clone issue first broke.

Dan Corbit wrote:
This is what Fabian said about Strelka:
"No worries as far as I am concerned.
Ideas are not a legal property.
The code was rewritten so it's OK with me.
Tournament organisers might think differently.
I cannot say a definite yes or no ..."

Some programmers found code similarities between Strelka and Fruit; Vasik said that Strelka was R1 beta; Fabien told Corbit that he didn’t mind about Strelka. When was all that?

I’m asking because I would like to know why these accusations take place now and not in the old times of Rybka 1 beta. And whether they are related to other accusations here last week about Rybka giving R2 for free and not showing the true node count. I’m not saying it’s a campaign, but it might very well look like it, with these three simultaneous accusations against Rybka just before China 2008 and immediately after the huge lead of Rybka 3.

By the way, when Vasik said that Strelka was R1 beta, was he referring to the whole program or to parts of it? If to parts of it, the whole accusing syllogism (part of Str = Fr, part of Ry = Str, therefore Ry = Fr) is false, because Strelka could have copied parts of Rybka code different than Fruit. Possible? I'm asking you as programmer. I'm lay.

As for your "Tournament organizers might think differently", Rybka 3.x will play in China, not R1 beta, so I don’t see on which grounds the organizers could object.

Enrique

It is not much of a stretch to believe that R2 has much of the same source as R1. And that R3 has much of the same source as R2. So _if_ R1 is a partial or complete copy of fruit, R1 is automatically GPL code. And unless R2 was 100% rewritten, R2 would also be GPL. Ditto for R3.

So we end up with a direct connection from fruit -> strelka -> rybka 1, with the probable connection of Rybka 1 -> Rybka 2 -> Rybka 3.

I have not been involved in discovering this, I have followed the discussions, and have stated several times that based on the evidence that has been presented, things appear to be a bit off-color. Since the Rybka group are offering no arguments or evidence to the contrary, it would be hard to draw any other conclusion.

You say "_if_" above, and then go on to "probable connection".

Methinks you should be extremely cautious before alleging a connection between R1->R2->R3 and then asserting a problem with R1.

Do you have evidence that R3 has R1 beta code contained within? If not, the comments above are exceptionally dangerous.

Did you read what I wrote? I wrote (and rewrote) "blitz" 7 times. _major_ changes. But big chunks of code were reused. Who needs a new opening book format, new PGN parser, new move input/output code, etc? I then rewrote Cray Blitz three times. Major changes. 20,000 lines of assembly language added. over a Period of several years. Yet each had at least 60% of code re-used. I have rewritten Crafty 3-4 times as it was time to clean up and re-do. And again, 50+ % (if not more) of the code was kept. The most recent rewrite where I eliminated all duplicate code was a big change, but tons of reuse.

I wrote above "It is not much of a stretch to believe that most of R1 source was retained and used in R2, and that most of R2 would be reused in creating R3." I see _zero_ danger there and if someone would want to challenge me on it, suits me. The university has a team of lawyers to handle such nonsense. I did not say "absolutely, R3 contains part of R1". I said "it most likely does" and I'd stake my software engineering reputation on such a statement any day of the week... The probability is _HIGH_ that if R1 contains GPL code, R2 and R3 also do. But even if not, if R1 contains GPL code, that could be a significant legal issue for someone if the FSF folks get interested.

_If_ R1 beta contained GPL code then the probability that R3, a commercial release through a publisher, contains any of that code is extremely low, not high. The simplistic assumption via the naming does not apply.

If you believe that, fine. Personally, I don't rewrite code that is working, that is functional, and that does exactly what is needed. I rewrite the parts that are being improved. That is a basic tenet of every software engineering book on the planet, AKA "code reuse". It is _the_ reason languages like C++ were developed, to make reuse even easier.

What you would do is not relevent. You are not commercial. Commercial software has to be clean without danger of challenge. A company with shareholders will be hit by a double whammy if it asserts it owns or licences assets which it knows are of dubious legality. Whammy one - get sued by the real owner. Whammy two - get sued by the shareholders for
not informing them, not putting aside money in the accounts for the risk, and positing untrue asset value statements.

No commercial company with half a brain will publish software claiming total rights over it if not true. That's the overpowering evidence one that R3 is clean. Chessbase won't licence it unless absolutely certain it's clean. That's overpowering evidence two. Say anything else and you play with fire. imo.

Sorry but that is naive. I have sold commercial rights to other programs. They included the standard disclaimer in the contracts that made it clear that any copyright issues would be mine and mine alone. I just did one of these 6 months ago with a company in the UK in fact. They don't have the time to do this kind of analysis, taking an executable from a competing program, disassembling it and comparing it to the source they are buying. It just doesn't happen.

I will also point out that some disassembled Rybka 1 (not beta) code has been posted, so this beta to release rewrite for version 1 is not based on reality.