Fabien's open letter to the community

[Zach Wegner]

Anthony concluded that it was perhaps a modified version of Fritz 5.
Anthony is most certainly an expert.

This is not too important to your main point, but I read Anthony's words mostly as "Strelka is very fast and simple", not as any interpretation of Strelka's origin. AFAIK Anthony hasn't publicly said anything about Strelka/Fruit.

[Alexander Schmidt]

I read HG Muller's earlier comment and I think he is about right that a re-write (eg. Strelka need not be GPL'ed) is legal and there is no GPL violation

So Rybka can only be illegal if he did copy_and_paste, otherwise it is legal - he did not tell.

If you start with the complete Fruit code and change it, is it copy and paste? Yes. It's a copy of the whole code. You answered the question yourself. Thats what happend with Rybka, there is no other logical explenation for the similaries in not chess related parts.

Nevertheless how often HG says something different, this is a fact. The only problem is to proove it. Thats why some people think: Noone can take legal action against me, so it is legal.

[Alexander Schmidt]

nonsense.

the Earth is flat...

[Xann]

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.

[Graham Banks]

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.

I'm afraid that I don't have the answers to any of those questions either. Perhaps somebody else might be able to help.

[Xann]

Wael - it was Stefan Meyer-Kahlen who had an exchange of emails with Fabien. You misread his post. Nobody can find any comment by Vas anywhere that he had contacted Fabien.
I know that you're angry that you feel let down by Vas, but facts are important.

I remember the contact with SMK, who I also met at WCCC 2005.

And you never know what this just reminds me of.
On Saturday I also read a post along the lines "But Fabien met Vasik at WCCC 2005 and did not say anything so he must be OK with Vasik".
This post was obviously not from Vasik, so there is much less of a chance that anyone remembers.
However it might be what Wael is referring to, who knows?

No Vasik at WCCC 2005 though.

Fabien.

You need to be very careful about what is true and what is not true.
Personally, I cannot recall Vas saying either of these things.

Cheers,
Graham.

I don't understand.
Either of what?

I did not mention Vasik saying anything in my post.

Fabien.

[Gian-Carlo Pascutto]

Maybe we can ask other people whether they would consider it a new engine.

What people think is in some way a moral issue. I never had the impression there were much people in computer chess concerned about morals. The interesting thing is if it is legal or not. (This, not much people care about either )

This is an interesting article on the subject, written by a lawyer which specializes in free software:

http://www.linux.com/archive/feature/113252

[Graham Banks]

You need to be very careful about what is true and what is not true.
Personally, I cannot recall Vas saying either of these things.

Cheers,
Graham.

I don't understand.
Either of what?

I did not mention Vasik saying anything in my post.

Fabien.

No problem . Misunderstanding.

[Uri Blass]

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.

The what is clearly not the same.

1)Fruit clearly has endgame knowledge that strelka does not have.
2)The mathrmatical function that the code implement is not the same(there are difference weights and strelka has material imbalance table that fruit does not have)

I compare the "what" simply by looking at analysis of different positions.
I can see that the what is often the same between Strelka1.8 and Rybka1 beta and I am not talking only about the same static evaluation but also about the same fail low or fail high behaviour(see my post early in this thread about strelka1.8 and Rybka1 beta analysis of the opening position when white starts without a queen).

[Watchman]

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?

for those wondering why the other thread disappeared: I made a mistake when trying to merge threads

http://rybkaforum.net/cgi-bin/rybkaforu ... l?tid=6772