Rybka's evaluation has been the subject of much speculation ever since its appearance. Various theories have been put forth about the inner workings of the evaluation, but with the publication of Strelka, it was shown just how wrong everyone was. It is perhaps ironic that Rybka's evaluation is its most similar part to Fruit; it contains, in my opinion, the most damning evidence of all.
Whoever wrote that has absolutely no clue what he is talking about. Fruit and Rybka evaluations are worlds apart. I am talking from a chess evaluation tuning point of view as I have no clue how the inner workings coding wise. But the output of Fruit evaluation when compared to Rybka evaluation is so different, as to make any comparison "chess wise" completely ridiculous. The main reason why Rybka gained so much ELO over all other programs is because it has a totally different static evaluation (especially in unbalanced positions) over any other program.
Rybka's evaluation has been the subject of much speculation ever since its appearance. Various theories have been put forth about the inner workings of the evaluation, but with the publication of Strelka, it was shown just how wrong everyone was. It is perhaps ironic that Rybka's evaluation is its most similar part to Fruit; it contains, in my opinion, the most damning evidence of all.
Whoever wrote that has absolutely no clue what he is talking about. Fruit and Rybka evaluations are worlds apart. I am talking from a chess evaluation tuning point of view as I have no clue how the inner workings coding wise. But the output of Fruit evaluation when compared to Rybka evaluation is so different, as to make any comparison "chess wise" completely ridiculous. The main reason why Rybka gained so much ELO over all other programs is because it has a totally different static evaluation (especially in unbalanced positions) over any other program.
Your statement is an opinion not supported by evidence. The quoted link above does have evidence, plenty of it.
Rybka's evaluation has been the subject of much speculation ever since its appearance. Various theories have been put forth about the inner workings of the evaluation, but with the publication of Strelka, it was shown just how wrong everyone was. It is perhaps ironic that Rybka's evaluation is its most similar part to Fruit; it contains, in my opinion, the most damning evidence of all.
Whoever wrote that has absolutely no clue what he is talking about. Fruit and Rybka evaluations are worlds apart. I am talking from a chess evaluation tuning point of view as I have no clue how the inner workings coding wise. But the output of Fruit evaluation when compared to Rybka evaluation is so different, as to make any comparison "chess wise" completely ridiculous. The main reason why Rybka gained so much ELO over all other programs is because it has a totally different static evaluation (especially in unbalanced positions) over any other program.
Whoever wrote that has absolutely no clue what he is talking about.
I wonder whether you looked at the code that accompanies the text within that document before you made such a derogatory statement. If you didn’t, I recommend that you do so now.
M ANSARI wrote:
I am talking from a chess evaluation tuning point of view as I have no clue how the inner workings coding wise.
In that case, perhaps a bit more humility and open-mindedness is called for. Someone has done a lot of work preparing that document.
The degree of arrogance, hubris and intellectual dishonesty displayed by some of the more experienced member of CCC is depressing. Sadly, you are not the only culprit, another one of our “esteemed” members not so long ago passed judgment that Zach’s work was insignificant because it only referred to the UCI parser. It turned out that he hadn’t even bothered to look at Zach’s work.
Osipov's speculation is not correct. Rybka is and always was completely original code, with the exception of various low-level snippets which are in the public domain.
Rybka's scores are minimax score - they are propagated up the search tree. In principle, they should be from the tip of the PV, but because Rybka takes the PV from the hash table, this may not always be the case.
Re. depth, this is simply a tool to drive the iterative search. By conventional I mean 'in the normal range'.
Hernandez: What chess engines in public domain, when you got started, had the biggest influence on the earliest versions of Rybka?
Rajlich: Well, actually I started in a kind of strange way. I printed out just about every single paper there was to print out about computer chess; all these academic papers. A lot of them are interesting, a lot of them are just really relevant, actually. (…) So I kind of started to work through that, that was how I started. Probably it’s not the most efficient way to do it. Probably the most efficient way is to take an open source program – at that point it would have been Crafty – and just kind of go through that. And I gradually worked around through that. (…)
There it is in bold just substitute the word Crafty with Fruit and that is the proof In every lie, there is always some truth.
Sean Evans wrote:
There it is in bold just substitute the word Crafty with Fruit and that is the proof In every lie, there is always some truth.
Cordially,
Sean
The 1st version of Rybka was before Fruit. It played in CCT tournaments although it did not do well.
Was it called Rybka at that time. I think he did take a lot from
Crafty before he came out with Rybka beta which he said he
took a lot from Fruit. I was one of the first to test the
Rybka beta versions that had the big elo jump. At that time he
said he took a lot of ideas from Crafty and Fruit.
Maybe Bob H. helped him on some things with Crafty ideas.
Best,
Gerold.
P.S. IMO at that time i think he gave the impression that
Rybka would be free and not be a comm. engine.
Harvey Williamson wrote:The 1st version of Rybka was before Fruit. It played in CCT tournaments although it did not do well.
The first version of Rybka was a joke. For ppl that can use their brain and have a bit of morality just the fact that Rybka suddenly, after Fruit appeared, gained 600 elo would be sufficient.
However, talking about morality in CC is like talking about virginity in bordel...
Sean Evans wrote:
There it is in bold just substitute the word Crafty with Fruit and that is the proof In every lie, there is always some truth.
Cordially,
Sean
The 1st version of Rybka was before Fruit. It played in CCT tournaments although it did not do well.
Hello Harvey,
Please!
The gap between that version and what later appeared would almost make the latter engine a totally new creature.
Please do not give the impression that its development was unrelated to Fruit.
Unlike Hiarcs, an engine of hard fought improvements and features, that later Rybka was from another planet.
Later.
I did not say anything of the sort just that the statement from Vas about looking at Crafty at the time was probably correct as Fruit did not exist. The program that played in CCT before Fruit was probably the basic shell a fast 64bit bitboard patzer.
18th WORLD COMPUTER CHESS CHAMPIONSHIP TOURNAMENT RULES
2. Each program must be the original work of the entering developers. Programming teams whose code is derived from or including game-playing code written by others must name all other authors, or the source of such code, in the details of their submission form. Programs which are discovered to be close derivatives of others (e.g., by playing nearly all moves the same), may be declared invalid by the Tournament Director after seeking expert advice. For this purpose a listing of all game-related code running on the system must be available on demand to the Tournament Director.
I think it is important for them to define the term derivative.
It is very clear that Rybka 1.0 uses Fruit ideas (I do not know how much is known about current Rybka versions). Does the use of these ideas make it (Rybka 1.0) a clone?
Consider that all chess programs use Alpha-Beta from John McCarthy's 1956 proposal. So under a loose definition, all programs are clones. So what *exactly* is a clone?
I completely agree with you.
Using ideas is not cloning.
It is curious how this Fruit-Rybka topic got so much attention and no one could prove anything serious so far.
The funny thing is that most people attacking Vas are only doing that because they believe in others "experts" statements. They don't have a clue about the "thing" itself, they just like pointing fingers. Poor sheep following the shepherd.
In every lie, there is always some truth. 
