Rebel wrote:Vas took the Fruit source code, wiped out the Fruit DNA, added 100 elo and released it under his own name.
This would also be my "most likely" reconstruction of events, though something like copying from one window to another is also a strong possibility (and the precise method of copying does not matter for most purposes in any case). Certainly he would then have had to splice in his material imbalance table, and probably it would be easier to use the bitboard code he already had rather than modify Fruit directly [on this and other points I disagree with FL's guess]. So maybe he created a Fruit/Rybka hybrid, and then over time wiped out the Fruit parts. Whatever the creation method, the various amounts of Fruit-like stuff in Rybka 1.0 make it hard for me to think that he didn't actually take some parts of the Fruit
code, even in your sense.
Rebel wrote:And therefore they signed the letter. The heart of the complaint is not the Fruit ideas in Rybka, the heart of the complaint is that they believed Vas copied.
Fabien's open letter (and the ensuing TalkChess thread, linked to by the Programmer's Open Letter) already make it clear that it is not about "code copying" in the strictest sense, and the oft-mentioned bitboard/mailbox distinction again makes it clear that the base-level "code" cannot be exactly the same. Letouzey's statement (about Strelka) was:
...it was not a verbatim copy of the source code. All the code had been typed (can't say "designed" though, see below) by an individual. So legally there was no issue that I knew of. It was however a whole re-write (copy with different words if you like, similar to a translation) of the algorithms. Not just an extraction of a couple of ideas as is common, and normal. I really don't see how anyone could think that the Rybka/Fruit complaint is merely about "code copying", at the very least it had to be about a "translation", which as FL says is "copy[ing] with different words".
Rebel wrote:And NO PROGRAMMER took offense in 2005 because it's generally agreed it's okay to do that AS LONG as you do not COPY and many programmers by their own admission did the same, taking from Fruit.
No programmer took offense in 2005, partly because Rajlich assured everyone:
As far as I know, Rybka has a very original search and evaluation framework. Furthermore, no one had much sense that Raljich had essentially re-used almost all of the Fruit evaluation features -- rather they thought he had taken some/many ideas here-and-there ("as is common", to quote FL from above), not a wholesale import of them.
Rebel wrote:Things changed when programmers started to believe Vas COPIED.
Things changed when people (thanks to disassembly) realised the great extent to which early Rybka versions were co-incident with Fruit, both in various coding quirks, and also in the evaluation function, to an extent much more than anyone else had expected (or would have done themselves). Things
really changed when Fabien Letouzey found out about this.
Rebel wrote:And some smart dude found the stick to punish Vas for what he (allegedly) did (copying Fruit) namely the cryptic ICGA rule #2 that can be interpreted in various ways. And this is THE MAIN THING I have against the verdict, if you are so convinced Vas copied, then PROOF IT. And the Panel couldn't, see the verdict. That's hypocracy.
The Panel was convinced that Rybka was not original, rather had its origins in Fruit (and Crafty), and thus broke Rule #2. The exact form of "copying" (whether "code copying" or "copy[ing] with different words") is not the principal point. I don't think Rajlich himself would argue that the early Rybka evaluation function was merely "an extraction of a couple of ideas" from Fruit, even if you granted a somewhat large "couple" due to his forwards/backwards statement. Rather he used what was essentially an extraction of the whole Fruit evaluation function, with various modifications (some quite significant, like material imbalance) and tuned numerology.
To take an early example: As is well-known, the program SARGON was published in "open-source" form in 1978, as a book. It was subsequently ported to many different computers. Did any of these people who made such a port try to enter it into a tournament, claiming they were the (sole) "author", rather than Dan and Kathe Spracklen? To your mind, did any of them "copy" SARGON; would you call their work "original"?
Rebel wrote:22. The programs have different Zobrist hash keys.
23. The programs have different user interface options.
Well, at least these last two were so ridiculous (or added too late) that you didn't have Riis copy them over to his Entertainment Computing article.