The post below is quoted with the kind permission of Chrilly and Enir(Enrique) and first published on the Rebel forum.DarkSide wrote:Hi Dr.
Doctor as you surely know, although since you has said previously that you don´t like chess and don´t pay attention to it, from end of year 2005 to today many people thinks that Rybka, that this in its version 2.3.à and that it has elo of 3100 in 4 processors can beat Hydra.
Could you give us an opinion about Rybka?
Do you have run some test of Hydra vs Rybka(or other engines)?
If so, what was the result?
Again I want to be thankful to you to answer amiably my questions.
Regards
Best wishes,
Harvey
Enir wrote:I asked Chrilly Donninger a couple of questions about Hydra and Rybka. These are his answers, that I post here with his permission. Chrilly asks me to "please stress, that its just a hypothesis and no theory." I ask everyone not to reproduce Dr. Donninger's statements below in any form anywhere else.
To my question "What do you think it would be the result Hydra-Rybka in a long match, with Rybka running on a fast quad, for example?", Chrilly answered:
"No idea. I visited last Saturday my old companion Heli Weigel in Vienna. He has build an own parallel system from off the shelf programms called Gecko.
Gecko used Rybka, Zappa and Naum as its basic engines. Rybka was clear, but why on earth Zappa and Naum instead of Fritz and Shredder. Heli informed me, that Zappa and Naum are better. I have heared at least from Zappa, but Naum was completly new to me. I am out of business. The only relation I have to computer chess in the moment are the monthly Hydra-$.
Hydra runs currently on some outdated FPGAs. They are 2 generations back. If Hydra makes a comeback into the computer-chess world we would have to make a new system. I think this system would be considerable stronger than the old one. I have learned some lessons in FPGA design and the new FPGA-chips are much more powerfull. Progress is very fast. Both in hardware, and in computer-chess."
My next question was "what the hell is the secret of Rybka? I find it hard to believe that its superiority is due to a better positional play. Better search once again?". Chrilly answered:
"I think its simple. Rybka has a big table with exchange relations of pieces.
E.g. in the simplest case: A bonus for the bishop-pair. But there are numerous other relations e.g. in the endgame.
Otherwise its basically Fruit. The programm is due to its simplicity very fast. The node count is a fake. They divide the number before sending it to the screen. Same holds for the search depth. The internal search depth is much deeper than the show on the screen. They cut off the principial varation. I have read many arguments, Rybka must be - due to its low node count - very intelligent. This intelligence is in the eye of the observer.
GM Lutz was never impressed by the chess knowledge of Rybka.
They have - in addition to Fruit - a threat extension in the search. If a move threats the opponent and the opponent answers the threat, the search is extended. Threat is defined very general as "the evaluation goes up by a certain amount". To answer the threat means: The evaluation goes down again to the original level.
Its a good mixture of simple ideas.
How to I know? There was a post on a Russion forum by a hacker who dissassembled Rybka. Everybody sayed, he just invents this and its not true.
But I have also disassembled some parts of the first Rybka Version. My findings are in aggreement with the statements of these guy. Maybe they have changed a lot in the meantime and I am speaking of a long outdated Rybka (see Zappa, Naum above). But usually one just adds a few things once one has a successfull version. I think there is no reason to write it completly new."
Unfortunately, I don't think that Chrilly Donninger will post here any time soon. He finds it fun to post in forums once every 2 years or so, but no more. So don't expect he will answer or argue.
Enrique
Heli informed me, that Zappa and Naum are better" It will a Heart break for Rybka fan´s 
I wonder how many time will happen before the other chess programmers (Mark, Amir, Frans etc) catch Rybka?