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Subject: Re: guilty until probed the opposite

Author: Roman Hartmann

Date: 04:51:05 05/29/05

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On May 28, 2005 at 18:38:51, Cesar Contreras wrote:

>To all of you:
>It seems to me like a witch hunting, i don't mean it's a bad thing to search for
>justice, what i mean it's that many are taking conclusions too quickly. I don't
>say "Fafis it's not a clone", but if it is, the evidence it's not conclusive.
>In the other hand, i see many efford (people/hours) in order to probe fafis it's
>a clone ... i hope there are at least some people thinking in some ways to probe
>it is not a clone... that can be called justice.
>"guilty until probed the opposite" it's just plain bad (some are taking out
>fafis from their tournaments). Why don't wait a little more?  why the hurry?

I agree, 'in dubio pro reo'. Personally I too would like that the ones who are
hunting for the clones would only go public after they are 100% sure that the
engine in question really is a clone (there is quite a lot of evidence that
Fafis is a clone though but no real proof yet). Furthermore I also agree that
the autor doesn't have to prove that he's innocent of cloning but rather the
ones accusing the programmer of cloning have to prove that. The author doesn't
have to release his sources to prove he's innocent.

>Some things i like to add:
>- I'ts important to know the names of the other 3 engines  that made the same
>moves as crafty in the draw game. The others must be clones also or this
>evidence it's irrelevant.

No, I completely disagree with that. Why spread rumours?

>- I'ts important to know the name of the other engine that made the same move as
>crafty in the mate on one. The other must be a clone also or this evidence it's

I guess the problem in the case of Fafis is the sum of similarities the program
shares with crafty. Still not proof for cloning, of course.

>- Crafty it's a center of knowledge in chess programming, so having programs
>that behave the same in some aspects or some positions don't seem to me that
>- The strings "captured a king" and "feature rejected by xboard" are not a good

I agree, the same string(s) in Fafis doesn't proof anything. The routines behind
could be very different.

>- The code needed to generate moves, parse FEN it's a little part of a chess
>program, you can't say it's a clone based on that little parts.

If you just copy the move generator of Crafty and also the part handling the FEN
strings you are certainly cloning. You would also depend on the same data
structures then that's a vital part of chess engines.

>- The virus thing can happen to all we engine authors, we are confident in our
>antivirus, but virus are first then antivirus, and some virus simply desactivate
>the antivirus. I think some pleople here just closing their mind, i can imagine
>a loot of ways the virus can get into the exe  (worm mutation, worm
>modification, bad information from antivirus companies). You can suspect that
>Rafael append the worm himself, but you can't be for sure.

Personally I can't imagine he put the virus into the program on purpose as that
would be just incredible stupid to do. I also think there are other explanations
for the virus beeing present in the program.

>As an engine author myself i think (IMHO) that the evidence it's not conclusive,
>i can imagine it's not dificult to find similar behaviors on some aspects on
>very diferent engines.

There is a lot of evidence for cloning in Fafis but no final proof, agree on

>With all my respect i think you must be more carefull when you release this kind
>of information, it must be released when you have enought evidence to probe it.
>Maybe you are rigth and Fafis it is a clone, but maybe not and one person it's

Agree on that, although the sum of evidence in the Fafis case is almost

>To the engine authors:
>- suposing you got conclusive evidence tell that Move generator and FEN parser
>it's crafty code? how mutch % of the code it is?
>- How do you feel if your engine it's declared a clone when you know it's not?
>You know you took some ideas from here or from there, but you know it's not a

Taking the move generator/FEN parser of another engine is a bit problematic if
you don't state that in your Readme files or don't have permission from the
author. If your engine is a derivative work of another engine you should state
that/should have permission to do so imo.

>- What it's the way to clean your name?
>- does Releasing your VERY OWN source code cleans your name? (but it's yours,
>you decide when to release it or not)
>- but you MUST release YOUR CODE or you must GIVE IT to somebody you don't even
>know if you want to continue in your hobby. :-(

The author doesn't have to release his code in order to prove he isn't cloning
imo. He doesn't have to prove anything at all. The ones accusing have to prove
(or collect enough evidence) that the questioned engine is a clone. Although if
I would be accused of cloning I would probably release some small parts of my
sources (data structure, parts of the move generator) just to point out the
differences to other engines.
But if you don't copy and paste code and don't dive too deeply into sources of
other engines there is probably no big chance left for beeing accused of cloning
and if so there isn't much to worry about.

best regards

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