Rybka 1.0 vs. Strelka

[chrisw]

It is well known fact. That is why those who knew it all the time are not worshipping Vas or rybka for that matter. However if you speak out loud you get silenced by the knights guarding the holy grail...

Cheers

"You must be motivated by jealousy or envy". That's the only counter argument. No wonder they are not silencing anybody with that.

// Christophe

You have to prove your case. The other side can remain silent in the meantime. In any case, how do they prove a negative? The onus is on you.

Proving they have no GPL code from Fruit (or any other program) is actually easy. But most likely not something they would want to do. If somebody accused me, I would just say "download the source from someone and compare with whatever you want...

Sounds like witchhunting method. See if she floats. If she does, burn her for witchcraft, if she sinks, she drowns anyway.

See the source, if innocent, you get to see the source, if guilty you get to see the source. Commercial programmer loses either way, like the witch.

The onus of proof remains on the accusers. Period.

i would expect and hope that the source wouldn't be made public for everyone to see, but simply presented to ... for ex: the FSF, or a expert for inspection.

almost every tournament has such a rule... i.e. if requested, the source code must be made available to the tournament director. i have no idea if this ever actually happens though.

It's a relatively recent rule, brought about by clones developed off publicly available sources.

The actual rule is:

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. (For interpretation,
see ICGA Journal, Vol. 29, No. 2, p. 94).

I would interpret this:

a) very strong evidence is required before activation of the 'investigation process'

b) this evidence would not be strong in the case of Rybka because it does not, or nobody has suggested, fulfill the requirement "playing nearly all moves the same".

c) the term "close derivatives of others" is clearly meant in an engine sense. bits of UCI and move handling code similarities won't be sufficient.

d) the definition "close derivatives of others" can be challenged by the accused programmer by pointing to a list of differences. ie this that and the other is different, therefore "close" doesn't apply, therefore no source.

e) to get vdH into a position where he can reasonably ask to see source code listings would require getting past (d) and providing substantial amounts of critical engine code disassemblies of the complained program together with the corresponding target listings. Even then he could well turn around, shrug his shoulders and say "no play moves the same, no derivative".

if vdH did ask for and obtain source listings there's no way he will do the comparisons himself. there'll be a team of 'experts' appointed. the 'experts' by definition will be other chess programmers, precisely the people who a commercial will not want to get to see the source. Their sight of the source is potentially and probably actually damaging, and that means that a 'light' decision to open up the sources is itself open to a subsequent legal claim.

[duncan]

If you could reply to this post by Mr Kaufman I would appreciate it


http://64.68.157.89/forum/viewtopic.php ... 30&t=23114

duncan

[Eelco de Groot]

If you could reply to this post by Mr Kaufman I would appreciate it


http://64.68.157.89/forum/viewtopic.php ... 30&t=23114

duncan

Hello Duncan

My count, using threadview it seems directed at Prof. Hyatt;
Bob Hyatt made eleven replies in your thread in this forum you are linking to, so it is not clear what you meant?

Regards, Eelco

[Uri Blass]

If you could reply to this post by Mr Kaufman I would appreciate it


http://64.68.157.89/forum/viewtopic.php ... 30&t=23114

duncan

Hello Duncan

My count, using threadview it seems directed at Prof. Hyatt;
Bob Hyatt made eleven replies in your thread in this forum you are linking to, so it is not clear what you meant?

Regards, Eelco

Bob Hyatt did not reply to the last post and the posts that he made earlier are not relevant because they are no reply to duncan's post that is the last post in the thread.

Uri

[Tony]

[snip]
No commercial company with half a brain will publish software claiming total rights over it if not true. That's the overpowering evidence one that R3 is clean. Chessbase won't licence it unless absolutely certain it's clean. That's overpowering evidence two. Say anything else and you play with fire. imo.

I think I have first hand experience on this and I know that you are wrong.

If you need examples, Verizon sued by BusyBox developers. Redhat v SCO, Sun v Microsoft. These occur all the time because major players push software that isn't "squeaky clean." So it's hard to use Chessbase's intelligence as proof of anything concerning Rybka 3.

Maybe. Reverse engineering Rybka 3 will prove whether or not it contains GPL code. Everything else is just speculative and damaging.

Enrique

No, not everything is speculative.
There's a mountain of evidence that strleka 2.0 has hundreds and hundreds of lines of code that are identical or equivilent to code found in fruit 2.1. (this comparison can be made even by a casual user...the two sets of source code are freely available). a detailed comparison was presented here:
http://64.68.157.89/forum/viewtopic.php ... ht=strelka

There is also evidence that strelka 2.0 (both source code and binary) is identical to rybka 1.0 beta.

In addition Vas has confirmed that Strelka is indeed his.

? I think the conclusion is not difficult to ascertain...
rybka 1.0 beta is a derivative of fruit 2.1

i volunteer to stir the shit....

What if there's a completely innocent explanation?

Even if there was, it would not be credible anymore.

There are only 2 solutions for this kind of accusations. You either react immediately (damage controle) or you keep silent and hope it blows over.

There is no (credible) middleway.

Tony

Deal done that you don't know about?

Team of programmers secretly working together on the project that you don't know about?

Key programmer working on the project who writes in his own style, that you don't know about?

Use your imagination, there's all manner of possibilities. Some perfectly benign. Before launching into condemnation.

You think it's credible if they came up with any of those explanations only now ?

EDIT I did not say there aren't any explanations. I said that by now the're not credible anymore.

EDIT BTW wich of the "explanations" you gave, explain the simmularities in code ?

Tony

[Terry McCracken]

It is well known fact. That is why those who knew it all the time are not worshipping Vas or rybka for that matter. However if you speak out loud you get silenced by the knights guarding the holy grail...

Cheers

"You must be motivated by jealousy or envy". That's the only counter argument. No wonder they are not silencing anybody with that.



// Christophe

You have to prove your case. The other side can remain silent in the meantime. In any case, how do they prove a negative? The onus is on you.

Proving they have no GPL code from Fruit (or any other program) is actually easy. But most likely not something they would want to do. If somebody accused me, I would just say "download the source from someone and compare with whatever you want...

Sounds like witchhunting method. See if she floats. If she does, burn her for witchcraft, if she sinks, she drowns anyway.

See the source, if innocent, you get to see the source, if guilty you get to see the source. Commercial programmer loses either way, like the witch.

The onus of proof remains on the accusers. Period.

Nonsense!

If Christophe or any other commercial programer wanted the source code of Rybka 3 they'd disassemble it. It's not that hard.

[Terry McCracken]

The topic came up in another thread about the issue of comparing Strelka to Fruit vs. comparing Rybka 1.0 to Fruit. I am doing some disassembling of Rybka 1.0, so I will post the assembly that is equivalent to the last piece of code I had in Fruit. Just to let you know, this is by no means complete. I have filled in most of the function names and some of the variable names, but there is a lot left to do. This is just the result of a few day's work, more will come later.

Code: Select all

.text:0040BCA0 start_search    proc near               ; CODE XREF:
start_go+35F p
.text:0040BCA0
.text:0040BCA0 var_44C         = dword ptr -44Ch
.text:0040BCA0 var_440         = dword ptr -440h
.text:0040BCA0 undo            = dword ptr -40h
.text:0040BCA0 var_8           = dword ptr -8
.text:0040BCA0 num_moves       = dword ptr -4
.text:0040BCA0
.text:0040BCA0                 push    ebp
.text:0040BCA1                 mov     ebp, esp
.text:0040BCA3                 sub     esp, 440h
.text:0040BCA9                 push    ebx
.text:0040BCAA                 push    esi
.text:0040BCAB                 push    edi
.text:0040BCAC                 push    offset dword_669C60
.text:0040BCB1                 mov     dword_667A0C, -500
.text:0040BCBB                 mov     dword_667A10, 500
.text:0040BCC5                 call    evaluate
.text:0040BCCA                 add     esp, 4
.text:0040BCCD                 test    al, al
.text:0040BCCF                 jz      short loc_40BD25
.text:0040BCD1                 mov     ecx, dword_669C6C
.text:0040BCD7                 mov     eax, dword_669C68
.text:0040BCDC                 not     ecx
.text:0040BCDE                 push    ecx
.text:0040BCDF                 not     eax
.text:0040BCE1                 push    eax
.text:0040BCE2                 push    offset list_root
.text:0040BCE7                 call    gen_evasions
.text:0040BCEC                 mov     ecx, list_root
.text:0040BCF2                 add     esp, 12
.text:0040BCF5                 xor     eax, eax
.text:0040BCF7                 test    ecx, ecx
.text:0040BCF9                 jz      short loc_40BD15
.text:0040BCFB                 jmp     short loc_40BD00
.text:0040BCFB ;
---------------------------------------------------------------------------
.text:0040BCFD                 align 10h
.text:0040BD00
.text:0040BD00 loc_40BD00:                             ; CODE XREF:
start_search+5B j
.text:0040BD00                                         ; start_search+73 j
.text:0040BD00                 mov     list_root[eax*4], ecx
.text:0040BD07                 mov     ecx, dword_66BC78[eax*8]
.text:0040BD0E                 add     eax, 1
.text:0040BD11                 test    ecx, ecx
.text:0040BD13                 jnz     short loc_40BD00
.text:0040BD15
.text:0040BD15 loc_40BD15:                             ; CODE XREF:
start_search+59 j
.text:0040BD15                 mov     list_root[eax*4], 0
.text:0040BD20                 jmp     loc_40BDC2
.text:0040BD25 ;
---------------------------------------------------------------------------
.text:0040BD25
.text:0040BD25 loc_40BD25:                             ; CODE XREF:
start_search+2F j
.text:0040BD25                 mov     edx, dword_667B9C
.text:0040BD2B                 mov     eax, dword_667B98
.text:0040BD30                 mov     ecx, dword_667B94
.text:0040BD36                 push    edx
.text:0040BD37                 mov     edx, dword_667B90
.text:0040BD3D                 push    eax
.text:0040BD3E                 push    ecx
.text:0040BD3F                 push    edx
.text:0040BD40                 push    offset dword_66C070
.text:0040BD45                 mov     eax, offset list_root
.text:0040BD4A                 call    gen_captures
.text:0040BD4F                 xor     esi, esi
.text:0040BD51                 add     esp, 20
.text:0040BD54                 cmp     list_root, esi
.text:0040BD5A                 jz      short loc_40BD6D
.text:0040BD5C                 lea     esp, [esp+0]
.text:0040BD60
.text:0040BD60 loc_40BD60:                             ; CODE XREF:
start_search+CB j
.text:0040BD60                 add     esi, 1
.text:0040BD63                 cmp     list_root[esi*4], 0
.text:0040BD6B                 jnz     short loc_40BD60
.text:0040BD6D
.text:0040BD6D loc_40BD6D:                             ; CODE XREF:
start_search+BA j
.text:0040BD6D                 mov     eax, dword_669C6C
.text:0040BD72                 mov     ecx, dword_669C68
.text:0040BD78                 push    -1
.text:0040BD7A                 push    -1
.text:0040BD7C                 push    -1
.text:0040BD7E                 push    eax
.text:0040BD7F                 push    ecx
.text:0040BD80                 lea     edx, [ebp+var_440]
.text:0040BD86                 push    edx
.text:0040BD87                 call    gen_quiet_moves
.text:0040BD8C                 mov     eax, [ebp+var_440]
.text:0040BD92                 add     esp, 24
.text:0040BD95                 xor     ecx, ecx
.text:0040BD97                 test    eax, eax
.text:0040BD99                 jz      short loc_40BDB5
.text:0040BD9B                 lea     edx, ds:66BC70h[esi*4]
.text:0040BDA2
.text:0040BDA2 loc_40BDA2:                             ; CODE XREF:
start_search+113 j
.text:0040BDA2                 add     ecx, 1
.text:0040BDA5                 mov     [edx], eax
.text:0040BDA7                 mov     eax, [ebp+ecx*4+var_440]
.text:0040BDAE                 add     edx, 4
.text:0040BDB1                 test    eax, eax
.text:0040BDB3                 jnz     short loc_40BDA2
.text:0040BDB5
.text:0040BDB5 loc_40BDB5:                             ; CODE XREF:
start_search+F9 j
.text:0040BDB5                 add     ecx, esi
.text:0040BDB7                 mov     list_root[ecx*4], 0
.text:0040BDC2
.text:0040BDC2 loc_40BDC2:                             ; CODE XREF:
start_search+80 j
.text:0040BDC2                 mov     esi, list_root
.text:0040BDC8                 xor     edi, edi
.text:0040BDCA                 test    esi, esi
.text:0040BDCC                 mov     [ebp+num_moves], edi
.text:0040BDCF                 jz      short loc_40BE4C
.text:0040BDD1                 mov     [ebp+num_moves], offset list_root
.text:0040BDD8
.text:0040BDD8 loc_40BDD8:                             ; CODE XREF:
start_search+1A7 j
.text:0040BDD8                 lea     eax, [ebp+undo]
.text:0040BDDB                 push    eax
.text:0040BDDC                 push    esi
.text:0040BDDD                 call    make_move
.text:0040BDE2                 push    offset pos_info_entry
.text:0040BDE7                 call    evaluate
.text:0040BDEC                 mov     ecx, dword_667C20
.text:0040BDF2                 lea     edx, ds:0[ecx*8]
.text:0040BDF9                 mov     ecx, offset dword_667BF8
.text:0040BDFE                 sub     ecx, edx
.text:0040BE00                 mov     eax, [ecx]
.text:0040BE02                 mov     ecx, [ecx+4]
.text:0040BE05                 and     eax, pos_info_entry
.text:0040BE0B                 and     ecx, dword_669C84
.text:0040BE11                 add     esp, 0Ch
.text:0040BE14                 or      eax, ecx
.text:0040BE16                 jnz     short loc_40BE1C
.text:0040BE18                 mov     bl, 1
.text:0040BE1A                 jmp     short loc_40BE1E
.text:0040BE1C ;
---------------------------------------------------------------------------
.text:0040BE1C
.text:0040BE1C loc_40BE1C:                             ; CODE XREF:
start_search+176 j
.text:0040BE1C                 xor     bl, bl
.text:0040BE1E
.text:0040BE1E loc_40BE1E:                             ; CODE XREF:
start_search+17A j
.text:0040BE1E                 lea     eax, [ebp+undo]
.text:0040BE21                 push    eax
.text:0040BE22                 push    esi
.text:0040BE23                 call    unmake_move
.text:0040BE28                 add     esp, 8
.text:0040BE2B                 test    bl, bl
.text:0040BE2D                 jz      short loc_40BE39
.text:0040BE2F                 mov     list_root[edi*4], esi
.text:0040BE36                 add     edi, 1          ; num_moves++
.text:0040BE39
.text:0040BE39 loc_40BE39:                             ; CODE XREF:
start_search+18D j
.text:0040BE39                 mov     eax, [ebp+num_moves]
.text:0040BE3C                 mov     esi, [eax+4]
.text:0040BE3F                 add     eax, 4          ; i++
.text:0040BE42                 test    esi, esi        ; list_root[i].move!=0
.text:0040BE44                 mov     [ebp+num_moves], eax
.text:0040BE47                 jnz     short loc_40BDD8
.text:0040BE49                 mov     [ebp+num_moves], edi
.text:0040BE4C
.text:0040BE4C loc_40BE4C:                             ; CODE XREF:
start_search+12F j
.text:0040BE4C                 xor     esi, esi
.text:0040BE4E                 cmp     edi, 1          ; if (num_moves <= 1)
.text:0040BE51                 mov     list_root[edi*4], esi ;
list_root[num_moves].move = 0
.text:0040BE58                 ja      short loc_40BE64
.text:0040BE5A                 mov     G_max_depth, 4  ; max_depth = 4;
.text:0040BE64
.text:0040BE64 loc_40BE64:                             ; CODE XREF:
start_search+1B8 j
.text:0040BE64                 push    esi
.text:0040BE65                 push    offset dword_667A28
.text:0040BE6A                 call    setjmp
.text:0040BE6F                 add     esp, 8
.text:0040BE72                 test    eax, eax        ; if
(setjmp(jmp_buffer) != 0) return;
.text:0040BE74                 jz      short loc_40BE87
.text:0040BE76                 mov     eax, offset byte_664E08
.text:0040BE7B                 call    sub_4092E0
.text:0040BE80                 pop     edi
.text:0040BE81                 pop     esi
.text:0040BE82                 pop     ebx
.text:0040BE83                 mov     esp, ebp
.text:0040BE85                 pop     ebp
.text:0040BE86                 retn
.text:0040BE87 ;
---------------------------------------------------------------------------
.text:0040BE87
.text:0040BE87 loc_40BE87:                             ; CODE XREF:
start_search+1D4 j
.text:0040BE87                 call    ds:GetTickCount  ; start_timer
.text:0040BE8D                 mov     start_time, eax
.text:0040BE92                 mov     eax, dword_66C490
.text:0040BE97                 add     eax, 1          ; All of this
stuff is trans_inc_date
.text:0040BE9A                 and     eax, 3
.text:0040BE9D                 mov     ecx, eax
.text:0040BE9F                 cmp     ecx, esi
.text:0040BEA1                 mov     dword_66C490, eax
.text:0040BEA6                 jge     short loc_40BEAB
.text:0040BEA8                 add     ecx, 4
.text:0040BEAB
.text:0040BEAB loc_40BEAB:                             ; CODE XREF:
start_search+206 j
.text:0040BEAB                 add     ecx, 1
.text:0040BEAE                 shl     ecx, 8
.text:0040BEB1                 mov     dword_66C498, ecx
.text:0040BEB7                 lea     ecx, [eax-1]
.text:0040BEBA                 cmp     ecx, esi
.text:0040BEBC                 jge     short loc_40BEC1
.text:0040BEBE                 add     ecx, 4
.text:0040BEC1
.text:0040BEC1 loc_40BEC1:                             ; CODE XREF:
start_search+21C j
.text:0040BEC1                 add     ecx, 1
.text:0040BEC4                 shl     ecx, 8
.text:0040BEC7                 mov     dword_66C49C, ecx
.text:0040BECD                 lea     ecx, [eax-2]
.text:0040BED0                 cmp     ecx, esi
.text:0040BED2                 jge     short loc_40BED7
.text:0040BED4                 add     ecx, 4
.text:0040BED7
.text:0040BED7 loc_40BED7:                             ; CODE XREF:
start_search+232 j
.text:0040BED7                 add     ecx, 1
.text:0040BEDA                 shl     ecx, 8
.text:0040BEDD                 add     eax, -3
.text:0040BEE0                 cmp     eax, esi
.text:0040BEE2                 mov     dword_66C4A0, ecx
.text:0040BEE8                 jge     short loc_40BEED
.text:0040BEEA                 add     eax, 4
.text:0040BEED
.text:0040BEED loc_40BEED:                             ; CODE XREF:
start_search+248 j
.text:0040BEED                 add     eax, 1
.text:0040BEF0                 shl     eax, 8
.text:0040BEF3                 mov     dword_66C4A4, eax
.text:0040BEF8                 xor     eax, eax
.text:0040BEFA                 lea     ebx, [ebx+0]
.text:0040BF00
.text:0040BF00 loc_40BF00:                             ; CODE XREF:
start_search+274 j
.text:0040BF00                 mov     killer1[eax], esi ; (Pos_info + i)->killer1 = 0;
.text:0040BF06                 mov     killer2[eax], esi ; (Pos_info + i)->killer2 = 0;
.text:0040BF0C                 add     eax, 32
.text:0040BF0F                 cmp     eax, 8192
.text:0040BF14                 jb      short loc_40BF00
.text:0040BF16                 mov     eax, 256
.text:0040BF1B                 mov     ecx, 768
.text:0040BF20                 mov     edi, offset History
.text:0040BF25                 rep stosd               ;
memset(History, 256, 12 * 64 * sizeof(int));
.text:0040BF27                 mov     eax, dword_667C40
.text:0040BF2C                 and     eax, dword_66C488
.text:0040BF32                 mov     ecx, dword_667C44
.text:0040BF38                 shl     eax, 4
.text:0040BF3B                 add     eax, dword_66C480
.text:0040BF41                 cmp     [eax], ecx
.text:0040BF43                 jnz     short loc_40BF4F
.text:0040BF45                 movzx   edx, word ptr [eax+4]
.text:0040BF49                 mov     dword_66C478, edx
.text:0040BF4F
.text:0040BF4F loc_40BF4F:                             ; CODE XREF:
start_search+2A3 j
.text:0040BF4F                 cmp     [eax+10h], ecx
.text:0040BF52                 jnz     short loc_40BF5E
.text:0040BF54                 movzx   edx, word ptr [eax+14h]
.text:0040BF58                 mov     dword_66C478, edx
.text:0040BF5E
.text:0040BF5E loc_40BF5E:                             ; CODE XREF:
start_search+2B2 j
.text:0040BF5E                 cmp     [eax+20h], ecx
.text:0040BF61                 jnz     short loc_40BF6D
.text:0040BF63                 movzx   edx, word ptr [eax+24h]
.text:0040BF67                 mov     dword_66C478, edx
.text:0040BF6D
.text:0040BF6D loc_40BF6D:                             ; CODE XREF:
start_search+2C1 j
.text:0040BF6D                 cmp     [eax+30h], ecx
.text:0040BF70                 jnz     short loc_40BF7B
.text:0040BF72                 movzx   eax, word ptr [eax+34h]
.text:0040BF76                 mov     dword_66C478, eax
.text:0040BF7B
.text:0040BF7B loc_40BF7B:                             ; CODE XREF:
start_search+2D0 j
.text:0040BF7B                 mov     eax, [ebp+num_moves]
.text:0040BF7E                 cmp     eax, 2
.text:0040BF81                 jb      loc_40C039
.text:0040BF87                 add     eax, -1
.text:0040BF8A                 mov     [ebp+var_8], eax
.text:0040BF8D                 js      loc_40C039
.text:0040BF93
.text:0040BF93 loc_40BF93:                             ; CODE XREF:
start_search+393 j
.text:0040BF93                 lea     ebx, ds:0[eax*4]
.text:0040BF9A                 mov     edi, list_root[ebx]
.text:0040BFA0                 cmp     edi, dword_66C478
.text:0040BFA6                 lea     edx, dword_66C074[ebx]
.text:0040BFAC                 jnz     short loc_40BFB5
.text:0040BFAE                 mov     ecx, 7FFFFFFFh
.text:0040BFB3                 jmp     short loc_40BFE1
.text:0040BFB5 ;
---------------------------------------------------------------------------
.text:0040BFB5
.text:0040BFB5 loc_40BFB5:                             ; CODE XREF:
start_search+30C j
.text:0040BFB5                 mov     ecx, edi
.text:0040BFB7                 and     ecx, 63
.text:0040BFBA                 mov     ecx, dword_667A90[ecx*4]
.text:0040BFC1                 test    ecx, ecx
.text:0040BFC3                 jz      short loc_40BFDF
.text:0040BFC5                 mov     esi, edi
.text:0040BFC7                 shr     esi, 6
.text:0040BFCA                 and     esi, 63
.text:0040BFCD                 shl     ecx, 4
.text:0040BFD0                 sub     ecx, dword_667A90[esi*4]
.text:0040BFD7                 add     ecx, 2147483391
.text:0040BFDD                 jmp     short loc_40BFE1
.text:0040BFDF ;
---------------------------------------------------------------------------
.text:0040BFDF
.text:0040BFDF loc_40BFDF:                             ; CODE XREF:
start_search+323 j
.text:0040BFDF                 xor     ecx, ecx
.text:0040BFE1
.text:0040BFE1 loc_40BFE1:                             ; CODE XREF:
start_search+313 j
.text:0040BFE1                                         ; start_search+33D j
.text:0040BFE1                 cmp     ecx, [edx]
.text:0040BFE3                 mov     esi, eax
.text:0040BFE5                 jnb     short loc_40C01F
.text:0040BFE7                 mov     eax, ebx
.text:0040BFE9                 lea     esp, [esp+0]
.text:0040BFF0
.text:0040BFF0 loc_40BFF0:                             ; CODE XREF:
start_search+37A j
.text:0040BFF0                 mov     ebx, dword_66BC74[eax]
.text:0040BFF6                 mov     edx, [edx]
.text:0040BFF8                 mov     list_root[eax], ebx
.text:0040BFFE                 mov     dword_66C070[eax], edx
.text:0040C004                 add     esi, 1
.text:0040C007                 lea     eax, ds:0[esi*4]
.text:0040C00E                 cmp     ecx, dword_66C074[eax]
.text:0040C014                 lea     edx, dword_66C074[eax]
.text:0040C01A                 jb      short loc_40BFF0
.text:0040C01C                 mov     eax, [ebp+var_8]
.text:0040C01F
.text:0040C01F loc_40C01F:                             ; CODE XREF:
start_search+345 j
.text:0040C01F                 sub     eax, 1
.text:0040C022                 mov     list_root[esi*4], edi
.text:0040C029                 mov     dword_66C070[esi*4], ecx
.text:0040C030                 mov     [ebp+var_8], eax
.text:0040C033                 jns     loc_40BF93
.text:0040C039
.text:0040C039 loc_40C039:                             ; CODE XREF:
start_search+2E1 j
.text:0040C039                                         ; start_search+2ED j

The interesting thing that I found is that for this piece of code, Rybka 1.0 is more similar to Fruit than Strelka. Here are the differences:
--Setjmp is called after the move generation, as in Fruit
--Something very strange: whereas in Strelka a failed setjmp call simply results in a return, in Rybka 1.0 it involves a function call, like in Fruit (there it is search_update_current()). The weird part is, it appears to be calling parse_position(). That is what the "call sub_4092E0" is for. Why would Rybka 1.0 be parsing the position after a setjmp call?
--The timer is started after the setjmp call
--depth is limited to 4 when there's only 1 legal move (commented out in Strelka, as noted in the other thread).
--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?

Time to Bump it Up!

[Guetti]

It is well known fact. That is why those who knew it all the time are not worshipping Vas or rybka for that matter. However if you speak out loud you get silenced by the knights guarding the holy grail...

Cheers

"You must be motivated by jealousy or envy". That's the only counter argument. No wonder they are not silencing anybody with that.

// Christophe

You have to prove your case. The other side can remain silent in the meantime. In any case, how do they prove a negative? The onus is on you.

Proving they have no GPL code from Fruit (or any other program) is actually easy. But most likely not something they would want to do. If somebody accused me, I would just say "download the source from someone and compare with whatever you want...

Sounds like witchhunting method. See if she floats. If she does, burn her for witchcraft, if she sinks, she drowns anyway.

See the source, if innocent, you get to see the source, if guilty you get to see the source. Commercial programmer loses either way, like the witch.

The onus of proof remains on the accusers. Period.

i would expect and hope that the source wouldn't be made public for everyone to see, but simply presented to ... for ex: the FSF, or a expert for inspection.

almost every tournament has such a rule... i.e. if requested, the source code must be made available to the tournament director. i have no idea if this ever actually happens though.

It's a relatively recent rule, brought about by clones developed off publicly available sources.

The actual rule is:

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. (For interpretation,
see ICGA Journal, Vol. 29, No. 2, p. 94).

I would interpret this:

a) very strong evidence is required before activation of the 'investigation process'

b) this evidence would not be strong in the case of Rybka because it does not, or nobody has suggested, fulfill the requirement "playing nearly all moves the same".

c) the term "close derivatives of others" is clearly meant in an engine sense. bits of UCI and move handling code similarities won't be sufficient.

d) the definition "close derivatives of others" can be challenged by the accused programmer by pointing to a list of differences. ie this that and the other is different, therefore "close" doesn't apply, therefore no source.

e) to get vdH into a position where he can reasonably ask to see source code listings would require getting past (d) and providing substantial amounts of critical engine code disassemblies of the complained program together with the corresponding target listings. Even then he could well turn around, shrug his shoulders and say "no play moves the same, no derivative".

if vdH did ask for and obtain source listings there's no way he will do the comparisons himself. there'll be a team of 'experts' appointed. the 'experts' by definition will be other chess programmers, precisely the people who a commercial will not want to get to see the source. Their sight of the source is potentially and probably actually damaging, and that means that a 'light' decision to open up the sources is itself open to a subsequent legal claim.

You seem to have sometimes a bit a special way of 'interpretation'.

b) I assume you know the difference between 'to be a requirement' and 'exempli gratia'.

c) I agree that bits of move generation and UCI handling is not enough to exclude somebody from the WCCC, at least in my opinion. Others use the same opening books, egtb code etc. (On the other hand, as a side note, it is enough to break the GPL).

[Dr.Wael Deeb]

It is well known fact. That is why those who knew it all the time are not worshipping Vas or rybka for that matter. However if you speak out loud you get silenced by the knights guarding the holy grail...

Cheers

"You must be motivated by jealousy or envy". That's the only counter argument. No wonder they are not silencing anybody with that.



// Christophe

You have to prove your case. The other side can remain silent in the meantime. In any case, how do they prove a negative? The onus is on you.

Proving they have no GPL code from Fruit (or any other program) is actually easy. But most likely not something they would want to do. If somebody accused me, I would just say "download the source from someone and compare with whatever you want...

Sounds like witchhunting method. See if she floats. If she does, burn her for witchcraft, if she sinks, she drowns anyway.

See the source, if innocent, you get to see the source, if guilty you get to see the source. Commercial programmer loses either way, like the witch.

The onus of proof remains on the accusers. Period.

Nonsense!

If Christophe or any other commercial programer wanted the source code of Rybka 3 they'd disassemble it. It's not that hard.

Are you sure about that

[GenoM]

Sounds like witchhunting method. See if she floats. If she does, burn her for witchcraft, if she sinks, she drowns anyway.

See the source, if innocent, you get to see the source, if guilty you get to see the source. Commercial programmer loses either way, like the witch.

The onus of proof remains on the accusers. Period.

Wise words. Can I see Strelka as a legal engine now after all these discussions?