Author: Dann Corbit
Date: 00:07:37 02/16/05
Go up one level in this thread
On February 16, 2005 at 01:39:47, Mridul Muralidharan wrote: >On February 15, 2005 at 21:08:08, Andrew Wagner 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? >>> >>>How about if the author rewrote the evaluation code and search algorithm only, >>>but left the hashing code, et. al.? >>> >>>How about if the author rewrote everything EXCEPT for the evaluation? >>> >>>How about if the author rewrote everything EXCEPT for Crafty's evaluation of >>>passed pawns? >>> >>>I think you can see where I'm driving. >> >>[snip] >> >>To add a completely useless illustration, this reminds me of an age-old riddle. >>A bald man is someone who has no hair. What about the person with one hair? >>Well, ok, for all intents and purposes, he's bald too. What about the guy with >>two hairs? You gotta admit, we would consider him bald, too. And you can keep >>going on like this. Where's the line? >> >>As was pointed out elsewhere in this thread, you can't "steal" a line like 'int >>i;'. That's just standard coding practice. But I think if there's some concept >>that an engine uses uniquely, that you use without giving credit, that's a >>violation of the GNU licensing agreement. I don't know that you can call the >>whole engine a clone, but that part of it is certainly inappropriate. > >Good point - and I like the analogy :) >In computer chess especially , there are hardly any "secrets" - yes there are >tuning params , variations of move ordering , pruning , etc - but all techniques >are "known" (well , commercials might have something "interesting" ;) ) >Eval is also an approximation and gross simplification of what humans consider. >So when will you start accusing someone of cloning ? >I think only the laziest of programmers who are cloners will get caught - sadly >:( with some imagination , I am pretty sure that even with most of the code >intact , you can make an undetectable clone of fruit or gnuchess or crafty. The effort to make something truly untracable (without damanging the program) is probably about the same as writing the program.
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