Posted: Sun Jun 27, 2010 1:06 pm Post subject: What do you folks make of this?
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Reading the forums regarding the Ipp* and family issue lead me to a very interesting post from Vas himself , this is a direct copy from the Rybka forum :
By Vasik Rajlich Date 2008-08-25 12:29 This discussion looks like a complete mess, I see wild statements like:
> --I noted earlier that the history initialization was different. Strelka and Rybka 1.0 are the same here, using memset(History, 256, 12 * 64 * sizeof(int)); But what I didn't notice is, 256 is out of range for an unsigned char. So that code is the same as Fruit's memset(History, 0, 12 * 64 * sizeof(int)); Why would Rybka 1.0 have 256? Is it the optimizer gone wild, or a deliberate attempt at obfuscation?
Maybe somebody can summarize the points.
Generally, code theft is easy to show - just show the two sections of identical code, side-by-side. There isn't much to debate in such cases. Rybka is of course original (with some accepted exceptions like bit scans & bit counters, etc). Strelka contains Rybka code. Whether Strelka also contains Fruit code, I don't know and don't really care.
Re. algorithms and structures - sure, you'll get a lot of similarity between programs. Take something like "modern move ordering" - by this, I mean hash move, non-losing captures (by MVV/LVA), killers, non-captures, and losing captures. The chance of two programmers settling on this independently is more or less zero.
Here we have a statement from Vas himself saying how easy it is to prove that the Ipp* and other are clones. Yet he has not done this ? I know some will say, "why should Vas have to do this ? " I answer, what harm can be done ? If they are truly clones, the open source of the Rybka code if already available all over the internet. Logically, it cannot make any sense. However, what does make appear to make sense is that this same conclusion that Vas came to also applies to parts of Rybka being a direct copy of Fruit. This would indeed explain his reluctance to come forth with evidence.
This is just one possibility among many, maybe Vas will still explain. I will not hold my breath.
