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back to article Chess crown stripped in plagiarism furore

Knights and pawns are being brandished in the rarified world of computer chess, with program Rybka and its developer Vasik Rajlich stripped of the world title on a charge of plagiarism. According to Chessvibes, the controversy has been simmering since February this year, when Rybka lost in a game against a rival program, Houdini …

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Defence? Of course it is

"although Rajlich repeatedly denied plagiarizing other programmers’ work, he didn’t offer “any kind of defence to the allegations”."

Surely, "didn't do it" is a defence? Chess programs only do so many different things, and if he wrote a chess propram that just "happened" to be very similar to another chess program, even though he had never seen the "other" chess program, is that plagiarism? No. There is no other defense he can present except that he didn't copy the other program.

This not a comment on whether or not he did it, simply a comment on the fact that you can't prove a negative, "prove you didn't copy it" = "prove there is no god." Can't be done, surely it should be up to the accuser to prove that he DID do it!

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Anonymous Coward

No evidence offered

@Steve Brooks: "There is no other defense he can present except that he didn't copy the other program."

A reasonable defence would be substantiated. Software doesn't pop out of the ether - he should have a supporting timeline for development, which may include code repository checkins, backups, etc. which demonstrate the evolution of his code. It's very common to have research documents, planning documents, pseudocode, algorithm diagrams, or other types of modelling. Simply saying, "I wrote it", without offering any evidence of your work is suspicious.

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Anonymous Coward

t's the SCOundrel gambit aka the Sicillian Attack

An unusual opening which can cause the game to go on for seven years but ultimately the initial weakness of "no evidence" leads to checkmate. Most of the moves take place off the board and include claiming to have used deep analysis that can't be revealed and claimng "all your moves are belong to us" and "nice restaurant you've got there"

anonymous because the the icon looks like a Venician carnevale mask and Venice is about as far away as you can get from Sicilly and remain in Italy

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Bronze badge
FAIL

Defence? Of course it is - not

Not true with software, if he created it he would have intermediate builds, maybe a few test routines, lots of documentation, possibly a flow chart or two, various code that failed and basically his archives or project management software should provide a history of code from an empty project to the finished item.

Alternatively when someone creates something by copying existing work then little if any of this would exist.

In order for a third party to prove plagiarism they would need access to his code to compare it with the alleged source.

I know nothing about the specifics of this case and have no opinion either way, I’m just pointing out that it not hard to disprove plagiarism in software design.

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Happy

Variable names

'Creative' variable names can also be useful.

It is quite concevible that an independent developer could come up with: "aiBoard", "nPawn" and "fnGambit".

It is a little harder to believe they coincidently chose: "aiFloor", "nCannonFodder" and "fnWTF_do_we_do_now".

Using 'r' instead of 'i' as a loop iterator could be enough.

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Bronze badge

He can't be required to prove that he didn't do it

(as you say, can't prove a negative), but he should be able to refute the evidence presented in support of the claim that he did do it?

Otherwise, all acquisitive crimes would go unpunished (the defence of "I've always owned this Mars bar/Lexus/fortune in unmarked sequential bills" would be foolproof).

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Silver badge
Trollface

prove there is no god...

err... ther isn't, im a grown up.

there is also no;

tooth fairy

santa clause

easter bunny

WMD in iraq

Higgs Boson

there all settled then :-D

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Boffin

@Dave Oakes

"if he created it he would have ... ... lots of documentation,"

Brilliant! That one made me laugh out loud!

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heh

Lazyness and Plagiarism is encouraged in programming is it not?

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Pint

Check mate - send him to the castle!

Check mate - send him to the castle.

Poor but couldn't resist.

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Anonymous Coward

the queens we use would not excite you

Good grief, it's vicious and cut-throat in the world of computer chess isn't it?

Will "I didn't do it, honest" become known as The Rajlich Defense move from now on? :-)

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Coat

Oops Busted

I guess you could say "Checkmate"

....ok i'm going :P

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Thinking 5 moves ahead

It's chess - presumably this is part of his strategy

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Meh

I'm confused...

...isn't the idea of Open Source that you CAN copy it and modify it....

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FAIL

Yes, if...

you're willing to share your modifications.

No, if you just want to snarf the code, tweak it a bit, and then sell binaries.

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Silver badge

Ah?

The Apple approach to open source, you mean?

BSD allows exactly the sort of thing you're talking about, which is why BSD is the favoured source for all greedy corporations on the lookout for some mug of a programmer to exploit.

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Anonymous Coward

Not *again*

@Robert Long 1: "The Apple approach to open source, you mean? [] greedy corporations on the lookout for some mug of a programmer to exploit"

Do we have to have misinformed sniping at Apple in *every* article? Perhaps you could lay aside your Apple obsession for a moment and take a look at what Apple *really* contributes to open source: http://www.opensource.apple.com/

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...but needn't be

>...isn't the idea of Open Source that you CAN copy it and modify it....

Yes - but you can't claim credit for it as your own work.

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Anonymous Coward

he didn’t offer “any kind of defence"

If I was him, I would have used the Sicilian defence by first moving my source code to c5.

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Coat

Oops

Sinclair C5?

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Happy

Was he distributing the binaries?

The exact licensing terms for the projects he copied may or may not have required him to share his source.

(L)GPL for example only requires him to share his source if he's distributing the binaries. (and only to whomever he distributed the binaries to).

If he's only *running* the program on a computer, then I guess it would depend on the legal view of whether that is "distributing the binaries" or not.

I am not a lawyer, so naturally that's just a layman's thoughts.

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Thumb Down

Commercially ...

... there was/is a commercial version, engine only, for £35 ish.

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WTF?

What the hell happened to presumption of innocence?

Since when did it become normal for the onus to be on the defendant to prove his innocence rather than on the plaintiff to prove guilt?

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@What the hell happened to presumption of innocence?

Presumption of innocence only applies to penal law, not to civil law or dealings between civil entities (as this is purely a case between a committee of some computer chess org and the programmer).

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Stop

Sorry, but...

Rybka has been around for ages, has gone through a few versions over that time which, until this year's tournament, played with increasing success (not to mention beating those programs it was allegedly cloned from). Isn't that a proof of evolution of it's code?

Someone mentioned SCO and this is exactly what the whole thing sounds, like "Linus was able to see our code and he made something that functions in a similar way to our software.", just swap Linus with Vasik.

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FAIL

There's quite a lot of evidence to say that he did copy the code

From: http://www.chessvibes.com/plaatjes/rybkaevidence/RybkaInvestigation.pdf

"Nearly the entire evaluation function is derived from Fruit. This includes

the formulas for calculating piece-square tables, methods and features of evaluating

piece mobility, rook king file proximity, rook and queen on the 7th rank, and king safety. "

"Disassembly of the root search analysis indicates nearly identical code and

variables, even including the ordering of the variables."

"Pre-Rybka 1.6.1 contains much identical code to Crafty, even including large

blocks of code with obsolete code inside them, and code that performs tests that make

no sense today (code that was left in Crafty by accident, by Robert Hyatt, also shows

up in Rybka 1.6.1). It is inconceivable that a second author could duplicate this code

purely by chance. At least hundreds of lines of code appear to be copied."

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