Fabien's open letter to the community

[Roger Brown]

Thank goodness it is all just a hobby!

Suppose it was serious, like football (not soccer!!)?

Later.

Would commercial interest qualify as serious?

Fabien.

Hello Fabien,

Perhaps my position on the issue of Fruit, cloning, borrowing and commercial interest are unclear.

Let me clarify in some small part.

For the record it does not matter to me if there are commercial interests or not. Wrong is wrong in my book, free or not.

Later.

[SuneF]

I took a brief at look at Fruit v2.1.2 and compared it to Strelka 2.0, there are many differences though.

* Strelka is all bitboard Fruit is not.
* Strelka has multiple specialized search routines for check and null windows, Fruit does not.
* Evaluation and move selection looks quite different.

Looks are not so important.

Several experts that possibly don't want to be mentioned plus myself concluded that Strelka contains a large amount of Fruit algorithms.
Ryan, however, did not see Fruit in Strelka.
Anthony concluded that it was perhaps a modified version of Fritz 5.
Anthony is most certainly an expert.

How are these differences possible?
It's because I, and I assume some others as well, look "through" the code all the way to what it computes (the mathematical function that the code implements).
And we compare what Strelka computes with what Fruit computes.
"What", not "how".
And we find a match.

Bob, does this makes sense to you?

Fabien.

I see you point but it's a difficult distinction to make.

A static exchange evaluator could be implemented in many ways but might result in the same functional behavior.

To us who don't see it perhaps you can point to some specific pieces of code that demonstrates the functional equivalence between Strelka and the original ideas in Fruit?

[SuneF]

I have always said that changing the infrastucture of move generation (e.g. from mailbox to bitboards) and then adapting (or "translating") the remaining source code is just another form of "copy and paste".
The result of the adaption is not a new engine.
As a chess programmer, I know what I'm talking about.

Matthias.

Well YMMV, I can see you and Fabian's point if it is 100% functionally equivalent. I very much doubt it will be 100% equivalent though. Changing the stuctures will mess everything up and in that process you will probably also try and improve on some of the ideas.
But if you think this is "just another form of copy and paste" I'd like to see you "copy" Crafty to a mailbox version.

Regardless of whatever copy right violation issues may be involved here, I still would not call the converted engine a clone or derivative. It would be too different for that.
And yes Matthias I know what I am talking about too, I have tried to convert Frenzee to mailbox - I call it Bandit and it is playing like crap in spite of my best efforts

[K I Hyams]

Somebody has posted a back up copy of that thread if you want to go take another look:
http://rybka.atspace.us/clon.htm
http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=6772

Thanks!

Back up copy?
Are you suggesting that the 2008 thread cannot be found by search anymore?

Somebody called "duncan" posted the following in this thread (this is an extract):
---
Stelka is not a clone, it's a Fraud. It is a direct Reverse Engineer of Rybka, and I can show you the exact constants, the exact math taken from Rybka, every function call in exactly the same location being passed exactly the same arguments, the same values and the same constants. A *direct* reverse engineering effort. There is no original content in Strelka, it is all a direct rip-off with some chunks of stuff left out.
---

Anyone remembers this or knows who "duncan" is?
The content of his post looks interesting too.

Now why would this precise thread move around a lot in 2011, I have no idea.

Fabien.

My main reason for posting here is to try to draw further attention to the pdf document to which Milos has linked.

You asked about the identity of duncan. I will send you a PM, rather than a suggestion in open forum, in case I am wrong.

[De Vos W]

I find your prejudice and intellectual dishonesty extremely irritating, please join the Rybka forum.

Hello De Vos,

Other persons may find other things extremely irritating about your presentations but I say that you should stay right here.



Later.

Actually I consider any dislike / rejection / attack I get from him as the best compliment a person can get, as for me he is the personification of evil, maliciousness and moral corruption on this forum. So anything that upsets or irritates him must be good and noble.

Hey Spartacus! Keep it cool it is time now! Go peddling some pieces with your infantile "Spartan Chess" I know you must have a hard time finding players for your crap game!
But just throw a little party with yourself...

[noctiferus]

my fault. Thx, Vytron.

e.

[Matthias Gemuh]

I have always said that changing the infrastucture of move generation (e.g. from mailbox to bitboards) and then adapting (or "translating") the remaining source code is just another form of "copy and paste".
The result of the adaption is not a new engine.
As a chess programmer, I know what I'm talking about.

Matthias.

Well YMMV, I can see you and Fabian's point if it is 100% functionally equivalent. I very much doubt it will be 100% equivalent though. Changing the stuctures will mess everything up and in that process you will probably also try and improve on some of the ideas.
But if you think this is "just another form of copy and paste" I'd like to see you "copy" Crafty to a mailbox version.

Regardless of whatever copy right violation issues may be involved here, I still would not call the converted engine a clone or derivative. It would be too different for that.
And yes Matthias I know what I am talking about too, I have tried to convert Frenzee to mailbox - I call it Bandit and it is playing like crap in spite of my best efforts

1) Crafty is not what I personally would pick for convertion (size of code).
2) Convertion is so much work that many people would do it only if they want to go commercial.

Convertion has the advantage that you know how strong "your" engine will be, if you don't mess up something.
You mention 100%. Why 100% ? Does 90% not qualify for cloning ?

BTW, when DanChess used substantial amounts of adapted Crafty eval, it was condemned as a clone

Regards,
Matthias.

[Matthias Gemuh]

... until there is consensus among the experts there can't be consensus among the croud.

... I am looking forward to the expert decision about these matters originating from Fruit. I don't think I am going to live for this to happen, however.

Some experts may have special agendas, so don't expect a consensus among the experts.

Matthias.

[SuneF]

1) Crafty is not what I personally would pick for convertion (size of code).

Fair enough. But Fruit was no small program to convert either.

2) Convertion is so much work that many people would do it only if they want to go commercial.

Convertion has the advantage that you know how strong "your" engine will be, if you don't mess up something.
You mention 100%. Why 100% ? Does 90% not qualify for cloning ?

To be functional equivalent it must be 100% identical in its output. That's was the argument as I understood it from Fabian. Because if it's not copied code and it is not performing the same, then by what metric are you going to identify them as being the same?
Basicly all programs are 90% the same anyway, all using hashing, nullmove, iterated deepening, mobility eval etc...
I worry with you strict definition of things that there are no original engines left, we are all cloning eachother basicly, even Fruit is just a few percent original code by this strict definition.

So I think that makes not much sense. The problem for us, are the ones that take Fruit or Ippolit, change a few eval weights, add another extension and call it their own engine. These are the ones we should look out for.

BTW, when DanChess used substantial amounts of adapted Crafty eval, it was condemned as a clone

Regards,
Matthias.

Right there are various degrees. I don't know about this specific case but in general copying or reusing code is the key thing to avoid.

[bob]

Just for the record, to eliminate this specific argument, when Zach, CT, I and others looked at the fruit/rybka1 question, we did _not_ involve Strelka. Strelka was the thing that exposed the issue, but we directly compared fruit to rybka, so the strelka issue could not be raised again...

What happened then?

Fabien.

We found _lots_ of similarities. Zach created a web page that went into great detail with the analysis. There are some obvious differences between Fruit and Rybka, but there are a _ton_ of similarities. Too many to be pure luck.