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401b48: 4b 8b 84 c8 40 a3 24 mov rax,QWORD PTR [r8+r9*8+0x24a340] 401b4f: 00 401b50: 48 85 05 39 ca 26 00 test QWORD PTR [rip+0x26ca39],rax 401b57: 75 3d jne 0x401b96 401b59: 83 c6 40 add esi,0x40 401b5c: 81 c7 00 01 00 00 add edi,0x100 401b62: 4c 85 f8 test rax,r15 401b65: 75 0c jne 0x401b73 401b67: 81 c6 cb 03 00 00 add esi,0x3cb 401b6d: 81 c7 ac 00 00 00 add edi,0xac 401b73: f6 44 24 31 80 test BYTE PTR [rsp+0x31],0x80 401b78: 74 2e je 0x401ba8 401b7a: 49 85 c5 test r13,rax 401b7d: 74 20 je 0x401b9f 401b7f: 48 8b 15 62 ca 26 00 mov rdx,QWORD PTR [rip+0x26ca62] 401b86: 83 c6 79 add esi,0x79 401b89: 48 85 d0 test rax,rdx 401b8c: 74 21 je 0x401baf 401b8e: 81 c6 55 03 00 00 add esi,0x355 401b94: eb 19 jmp 0x401baf
The above is the complete disasembled part of Rybka 1.0 beta which is supposed to mean the Fruit Rook evaluationcurrently under the microscope. We see (just) 19 ASM instructions and YET already notice 3 main obstacles.
- Mailbox (Fruit) vs Bitboard (Rybka), those pesky bitboards again, but so is the life of a reverse engineering programmer who wants to proof RYBKA=FRUIT.
- That the reverse engineering programmer knows (or should know) the rules of the game that state a lot of information during compilation is lost due to Optimizing Process of the compiler and he can not ASSUME constant folding as evidence without a word of warning to the readers of his document.
- Assumption two, that Vasik must have rewritten the Fruit two steps evaluation process via the op[me] and eg[me] arrays to Rybka one step direct evaluation and claim copying c.q. semantic equivalence nevertheless.
That's too much assumptions for just 19 lines of ASM code.
Fruitification in denial
Bad science
As demonstrated above we have evinced that the Rook evaluation in Fruit and Rybka are different and therefore it's dubious to make it a convincing case for copying or semantic equivalence.
If it were the case the Rook evaluation were an exception it could be tolerated. Problem is, it's not an exception but a pattern. See the long list of (fundamental) differences between Rybka and Fruit elsewhere.
When confronted with the evidence the main accusers Robert Hyatt, Mark Lefler, Wylie Garwin, Zach Wegner and Mark Watkins responded as follows:
Wylie Garwin: promised an answer but never gave one.
Robert Hyatt: This is simply another example of "highly deceptive and dishonest statements."
Mark Lefler: offering only assumptions while different is just that, different.
Zach Wegner: no single reply.
Mark Watkins: I think the case for "copyright infringement" (or plagiarism) of the evaluation function as a whole is quite weighty
All in denial which is far more worse than the fruitification issue itself. These were the leading people responsible for the ban of Vasik and the chaos in computer chess land that came after that.
- In science, unfolding a constant "A" into "B - C" just because you assume it is justified, without any explanation, is literally, academic dishonesty. In science you are supposed to present the data as it is, transparently. The fact that the 5 accusers do not realize how bad this is I consider problematic.
- The other denial of unburden evidence, that adding to score is principally different.
Fruitification case 2
The material table
Zach Wegner: The material tables in Rybka were one of the more interesting features introduced. Their implementation was a new way to evaluate material imbalances. The indexing and evaluations in the table seem to be unique,but there are some very interesting similarities in the information stored in the table with Fruit.
This is one of the worst examples in Zach Wegner's document, another example of fruitification Rybka to make it look like Fruit.
First of all Fruit has NOT a material table such as Rybka, Fruit has a hash-table that is maintained during search whereas Rybka has a fixed large pre-computed material imbalance table inside the executable with a size of over 1MB.
Rybka has almost all things different compared to Fruit but in the Wegner's document it is almost identical. Read carefully further:
Zach Wegner: There are a set of flags in Fruit that are not in Rybka. All of these (DrawNodeFlag, MatRookPawnFlag, MatBishopFlag, and MatKnightFlag) are not included in Rybka because it does not have any separate endgame knowledge, which is the purpose of all of these flags in Fruit. Rybka has all other flags that are in Fruit, and also an additional lazy evaluation flag. Fruit does not have lazy evaluation, so there is no flag in it.
From Fruit 2.1, material.h: const int DrawNodeFlag = 1 << 0; const int DrawBishopFlag = 1 << 1; const int MatRookPawnFlag = 1 << 0; const int MatBishopFlag = 1 << 1; const int MatKnightFlag = 1 << 2; const int MatKingFlag = 1 << 3; E>
Meaning, Fruit has six flags. Four of them (as Zach admits) are not in Rybka. But then Zach continues Rybka has all other flags that are in Fruit. 6-4=2 means all Zach? And further down in the Zach document we read looking at the left-to-right comparison that the "MatKingFlag" implementation is similar (but different), and that the "DrawBishopFlag" implementation is (said to be) the same but its usage is completely different in Rybka.
Apology
When faced with a critical opposition Zach apologized on August 22, 2011 in the following way:
This analogy only makes sense if you believe that the people claiming that R1 is a Fruit derivative are deliberately misleading. I know you can't take my word for it, but I certainly haven't been trying to mislead.
In retrospect, I regret only publishing evidence relating to the evaluation, since it's fuzzy in many ways, and people can easily see it as "circumstantial". A lot of the evidence hasn't even been written up properly. I view this as my own failure in many ways, but there's only so much effort I'm willing to put into this.
As already said young Zach is forgiven and none has questioned his integrity. Nevertheless the question remains how much influence the guilty style of his document has had on the 14 Panel members that voted Vasik guilty.
Thanks for listening.
Ed Schröder
Deventer, October 4, 2011
Netherlands
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