Hallo Karl-Heinz (und bei der Gelegenheit ebenfalls: Hallo Peter),
Zitat:
Wenn in Ippo & Co. die gleichen Bewertungs-Parameter zu finden wären wie in Rybka, hätte sich der Klone-Verdacht erhärten lassen.
Hierzu passend (so hoffe ich doch) kann ich nicht umhin immer einmal wieder einige (wie ich finde, bedenkenswerten) Stellungnahmen von Larry Kaufman zu zitieren (Hervorhebung von mir):
Zitat:
It runs thru the plies much faster than R3, even a bit faster than R3 on two cores (adding 3 plies to R3 reported depths for a fair comparison). Apparently the cloners did a good job of choosing which eval features were essential and which ones were barely worth the slowdown. All the eval added from R2 to R3 slowed R3 down by nearly as much as the reported speedup in the clone, and if some of the best R3 eval changes were kept and if code in R3 intended to make cloning difficult were removed this would pretty well explain the results. Maybe also the cloner found ways to optimize the code a bit while doing all the decompiling and analyzing the program.
I think people are just playing word games here.
It is obvious that it is not a pure clone, but it is equally obvious that it is a near-clone. One of the tables in the eval is nearly identical to the one I submitted for R3, just some tiny variations (mostly 1/100 of a pawn); I didn't check other tables but it's probably the same story. If you compare evals at fixed depth with R3 1 cpu and remember to add the plies to R3 the scores are usually far closer than with any other program. One exception is positions with a material imbalance (involving pieces); then they can differ quite a bit, as do R232 and R3.
One point to make is that my testing pretty well established that if you speed up a program at the expense of knowledge, it will tend to test well against the slower version of itself, but the "smarter" program will tend to test better against other programs. So before concluding that the clone is stronger than R3 I would need to see a lot of data against unrelated engines, not head-to-head results. It is also true that a faster, dumber program should test increasingly poorly at longer time controls, though I think the first point about playing unrelated engines is more important.
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=215851;hl=Zitat:
Well, to be precise a new program that was clearly made by decompiling Rybka 3 and putting it back together with changes to the evaluation function published its source code. So not the entire R3 code is public, but most of it other than the exact evaluation function is. The "author" does not publicly admit that his program was taken from R3, but Vas has said so and I can tell you that the similarities are so overwhelming that any claim to the contrary is a joke.
http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=215772;hl=Gruß
Axel