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Subject: Re: What constitutes a clone?

Author: Uri Blass

Date: 17:28:47 02/15/05

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On February 15, 2005 at 19:31:58, Dann Corbit wrote:

>On February 15, 2005 at 18:38:43, John Merlino wrote:
>
>>I'm not trying to start a brutally long thread here, but I'm just curious about
>>how people feel about a particularly touchy subject -- clones. What, in your
>>mind, would lead you to the conclusion that an engine is a clone?
>>
>>Let's forget trying to find ways to PROVE that a clone is a clone; I'm just
>>trying to define one. For the sake of argument, assume that the author of this
>>engine in question tells you exactly what he did and did not do, and you must
>>decide whether to call it a clone or not.
>>
>>Here are some hypothetical questions to start the debate:
>>
>>If the author took Crafty and completely rewrote the evaluation code and nothing
>>else, would it be a clone?
>
>Yes.  If you violate the rules of the software agreement, it is clearly a clone.
>
>>How about if the author rewrote the evaluation code and search algorithm only,
>>but left the hashing code, et. al.?
>
>Clone.
>
>>How about if the author rewrote everything EXCEPT for the evaluation?
>
>Clone.
>
>>How about if the author rewrote everything EXCEPT for Crafty's evaluation of
>>passed pawns?
>
>Clone.
>
>>I think you can see where I'm driving. Obviously, many engine authors have
>>studied Crafty and other engines whose authors have graciously provided their
>>source code. But, for an engine to not be considered a clone, does it have to be
>>absolutely 100% the work of the author? (Forget about Nalimov's EGTB probing
>>code and any other code that can be used with permission).
>>
>>Many thanks in advance for your thoughts,
>>
>>jm (who's just preparing for any eventuality during his upcoming stint as
>>moderator :-)
>
>If there is one single line of Crafty code used without permission or
>acknowledgement then it is a clone.

No
There can be one single line even by accident.
one line from Crafty's code is
int      phase;

You cannot blame every program that include this line to be a crafty clone.

Uri



Uri



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