The Strelka affair to date

Discussion of anything and everything relating to chess playing software and machines.

Moderators: bob, hgm, Harvey Williamson

Forum rules
This textbox is used to restore diagrams posted with the [d] tag before the upgrade.
Chan Rasjid
Posts: 567
Joined: Thu Mar 09, 2006 3:47 pm
Location: Singapore

Re: The Strelka affair to date

Post by Chan Rasjid » Tue May 15, 2007 8:23 am

Hello Fernando,
Do not be so fast in pressuming I do not know nothing about chess programming. Certainly I am not programmer, but I do know what null move is....
It is better not!

I have written a fully working program with hashing, rather complicated, and can easily add nullmove, etc...but I don't have a clue what Thomas Mayer's main post meant. I probably could learn about those things if I put enough effort. I don't even know what Christopher Conkie meant with white-to-move in the original board and how it can infer similiarity of programs. And Cristopher Theron mentioned only Rybka (and Strelka ?) only may get mate-in-30 at ply 4...but this I seem to understand as mate-in-30 generally may be detected searching till ply +-30.

So the story continues...whether Fabien decompiled and learned from Shredder and SKM decompiled and learned from Fritz, .... Vasik decompiled and learned from Glaurung....and Chrilly Donninger decompiled Rybka and put such knowledge to good use in Hydra...

I'll leave such things to the experts.

Best Regards,
Rasjid
Don't believe when you're told "There's no free lunch!" There is Linux.

GS

Re: The Strelka affair to date

Post by GS » Tue May 15, 2007 10:07 am

Chan Rasjid wrote:Hello Fernando,
Do not be so fast in pressuming I do not know nothing about chess programming. Certainly I am not programmer, but I do know what null move is....
...
.... Vasik decompiled and learned from Glaurung....
Best Regards,
Rasjid
No need to decompile Glaurung ;-)

Guenther

User avatar
Sylwy
Posts: 3358
Joined: Fri Apr 21, 2006 2:19 pm
Location: IASI (Romania) - the historical capital of MOLDOVA

The condition of Strelka

Post by Sylwy » Tue May 15, 2007 11:49 am

Hi all !

To establish if Strelka is (or not) a clone seems to be very close to the following dilema:

the decease of a person must be established by:
a. 1 (2-3 ) legist Doctor,or
b. a detailed examination by the whole community ??????

Have a nice day,
Sylwy
:D

User avatar
Thomas Mayer
Posts: 383
Joined: Thu Mar 09, 2006 5:45 pm
Location: Nellmersbach, Germany

Re: The Strelka affair to date

Post by Thomas Mayer » Tue May 15, 2007 12:30 pm

Hi Chan,
Chan Rasjid wrote:[...]
I have written a fully working program with hashing, rather complicated, and can easily add nullmove, etc...but I don't have a clue what Thomas Mayer's main post meant.
[...]
well, I would like it more when you leave me out of discussion, a) my posting was written before Bryan & Dann posted their conclusion and b) I wrote it now several times that for me the vote by Bryan & Dann is final.

The only way how Strelka could be a clone of Rybka is by thinking the unthinkable: either he had fully decompiled and understood Rybka or he got the source code of Rybka in hands.

Anyway, some words about my post: Fernando had written that nobody should say anything about Strelka being derived from something as long he hasn't any proofs... I don't know why he has written that, it seems to me that he didn't read what was written about Strelka in all the forums (And then you should read the germans & russian forums as well) and therefor wasn't informed. Also he doesn't understand that a lot positions discover similar (or mimicri of similar) programming technics. Therefor I thought I should give him some positions.
How did I get the positions ? Well, that's the interesting thing: I went to the old CCC archives and started with the first positions that showed anomalies of Rybka 1.0 beta directly AFTER it's release. You can go yourself to the archives and will see that I didn't jump over some anomalies just to hide differences -> I just took position by position as long they showed programming technics and have a different theme. (So not two Zugzwang problems, two underpromotion problems etc. - one exception because both don't solve one zugzwang problem but another one which is for me really interesting but as somebody already pointed out Fritz 8 has the same behaviour (but not Fritz 9, Fritz 1-7 nor any other engine I know of))
The outcome of that was at the start pretty unclear for me but finally the behaviour and also the moves were so much equal that I myself was pretty sure that this can't be random. Of course Fernando pointed out that after all we know right now it wasn't enough to make a conclusion because it leds to the wrong conclusion. The interesting thing is that in the past based on less indications engines were and still are treated as clones. So when our clone detection system doesn't work for Strelka it isn't unlikey that it didn't work in the past as well and we have engines on some well known clone lists which are there for wrong reasons.

Some words on known clones:
a) we have the most stupid ones which just rename the executeable, patch the name in the executeable to something different. Those are easy to discover, you must just find the base version and then they should be compareable node by node.
b) next thing are the clones based on open source. Well, it depends on the knowledge of the cloner, the more they change the more difficult it gets to uncover them. E.g. when you change a lot of evaluation values and maybe some stuff in the move ordering and of course all texts, number of shown nodes per second (just multiply or devide them), how depth is shown (add, subtract something, count totally different, whatever) then it is hard to discover them, most usual chess positions wont work. Therefor you take positions that discover programming techniques, e.g. how and when it detects zugzwang, how the nullmove works, has it special mate detection system, special move ordering, does it crash in some situations, does it show special behaviour in illegal positions, underpromotion stuff, how it presents mates (matescore), how is his hash working (fine 70 for example)... etc. etc.
Of course you will find similarities among ALL programs even when they are totally different. Fernando pointed that out: they play chess and are good in that, so it's likely that they play similar moves in a lot positions. The best things in fact are bugs or situations where they crash: same bugs are a good indication. Anyway, this ALL isn't a real proof, because you can't compare the sources - the only way to be sure finally, but when you found an exceptional number of same techniques, bugs, behaviour, whatever it is clear that it gets more likely that something isn't so independant then the author wants to have it. BUT you can be wrong in that - as we were with Strelka. And believe me, after randomly taking positions out of the archive I was VERY sure that something is fishy, in fact I have never seen something similar and I compare programs since VERY long now.
c) a c-type clone would be a clone of a private not open source that doesn't belong to a-type. Thinkable is that it either was created by disassembling or decompiling or that it was created with the original source. So far I have only one c-type clone in mind, Greif. I don't know whether it really was proven by comparing source or whether they only had indications like described in b) -> Such a clone could be even created by the author of the original engine and to discover this you definitely have to have BOTH sources. Of course it's unclear why an author should do that, but well, this is just about what type of clones COULD exist. So I believe the last one can not be discovered at all, because the author would never allow a comparisson of the code and himself - when asked - might answer that they are independant.

Greets, Thomas

User avatar
Daniel Mehrmann
Posts: 855
Joined: Wed Mar 08, 2006 8:24 pm
Location: Germany
Full name: Daniel Mehrmann

Re: The Strelka affair to date

Post by Daniel Mehrmann » Tue May 15, 2007 1:03 pm

I fully agree with Thomas here. I also wanna say that the statements of Dann and Brian are final for me.

But i want to say some basic words about the stuff going here. I think clone stuff or engine which are under observation should be only evaluated by programmers or your well known experts.
The user should be keep out, because the background knowledge isn't the same like a programmer (not all of course, but the most). I observed a lot of bad postings here which presenting no facts and just emotions. That is pretty bad.
Also a lot of programmers writing nothing here , because they fear the users acting like a ocean full of sharks. This shouldn't happend and the community should think about it.

Just my two cent,

Daniel

User avatar
Mike S.
Posts: 1480
Joined: Thu Mar 09, 2006 4:33 am

Re: The Strelka affair to date

Post by Mike S. » Tue May 15, 2007 3:15 pm

Thomas Mayer wrote: either he had fully decompiled and understood Rybka or he got the source code of Rybka in hands.
On March 16th, a poster "Rybkin" claimed to have decompiled and analysed Rybka's code, and wrote a lot about programming details:

http://kasparovchess.crestbook.com/view ... hp?id=1490
(can be translated to english by online translators)

I have posted that link on Thursday, but maybe it wasn't noticed yet, that it is related to the current discussion. Strelka was presented on that same message board, some weeks later. - Of course, in itself that proves nothing, but it is another little part of a big picture.
Regards, Mike

User avatar
fern
Posts: 8755
Joined: Sun Feb 26, 2006 3:07 pm

Re: The Strelka affair to date

Post by fern » Tue May 15, 2007 3:49 pm

Strelka and Rybka are the similar in some ways...."
That you said... "IN SOME WAYS"
I am not going even to intent to decypher how that is enough to talk of cloning.

My best
Fernando

User avatar
GenoM
Posts: 910
Joined: Wed Mar 08, 2006 8:46 pm
Location: Plovdiv, Bulgaria
Contact:

Re: The Strelka affair to date

Post by GenoM » Tue May 15, 2007 9:43 pm

fernando even we both are similar in some ways :)
take it easy :)

Chan Rasjid
Posts: 567
Joined: Thu Mar 09, 2006 3:47 pm
Location: Singapore

Re: The Strelka affair to date

Post by Chan Rasjid » Tue May 15, 2007 10:05 pm

Hello Fernando,
Strelka and Rybka are the similar in some ways...."
That you said... "IN SOME WAYS"
I am not going even to intent to decypher how that is enough to talk of cloning.

My best
Fernando
"In some ways" is correct - that's how some clones were found as they displayed unusual similarity, and maybe too often, which betrayed similar code blocks somewhere or copying implementations of some algorithms. But this may require relevant technical expertise!

By complete silence or no one willing to post any "similarity", there will never be any clone-busting.

For me personally, no clones ever exist!!!

Best Regards,
Rasjid
Don't believe when you're told "There's no free lunch!" There is Linux.

Post Reply