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Subject: Re: Bionic Vs Crafty Debate: some data required

Author: Ulrich Tuerke

Date: 05:51:16 01/25/99

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On January 25, 1999 at 08:24:14, Fernando Villegas wrote:

>Hi:
>I have been amazed a little bit by the fact that in the long thread about bionic
>as a clone or not  nobody seems to have given data about how much Bionic is
>really something new or not, to begin with. The only thing that has been said
>about his presumed novelty is Dgeordge Vidanovic's statement that it is new;
>only thing that has been said about his presumed clone quality is the afirmation
>by Bob that a program that has changed only 1% of the code cannot be considered
>something new. Well, which are the data to support one or the other statement?
>Maybe also some elaboration would be needed. By example, how much percentage of
>code change it is neccesary to talk of a change? It is enough a different
>behaviour of the engine?
>By the way, this last point could be deceiving. I can change dramatically the
>behaviour of CM6000 just altering strongly one of the paremeters of the code,
>say, putting the queen value at only 0.5 pawns. I bet that that would be enough
>to get an extremely different PV from the engine.
>Fernando

I am afraid that there can be no satisfactory answer to the questions about
originality of a clone program (except for the trivial case where the clone is
just a copy). The source code must not give many hints either. E.g., it is very
easy to let source code look completely different without changing the
algorithms. A quantitative measure in terms of percentage changed or so doesn't
make much sense. It is important to evaluate what had been changed. IMHO, search
or evaluation would be a more essential modification than i/o routines.

Next question would be, if the modifications are sufficiently large/original to
have a different program. There could be as many opinions as dicussion members.
For instance, a change in just one evaluation parameter could result in a very
different play of the program. So, it is an essential change, might even result
in raise of program's ELO strength ?

I do not envy ICCA for the task to evaluate the case of a clone participant in
Paderborn this year. (Hopefully, there will be no clone; at least my GNU clone
will not be there.)

What counts in the present case for me is, that Hans has made known to us that
his program is based on Crafty. He wasn't forced to do so. I guess that nobody
would have noticed at all if he hadn't told us. This is the easy case, where the
"clone author" gives sufficient credit to the "original author".

However to evaluate whether Hans' changes are essential is probably an
impossible task. I would suggest to stop the debate.

Far more nasty are the hidden clones, if they are there at all.

Regards,
Uli



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