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Subject: Re: definition of clones: Danchess an Crafty

Author: Robert Hyatt

Date: 11:36:56 02/15/04

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On February 15, 2004 at 13:41:42, Uri Blass wrote:

>On February 15, 2004 at 13:29:16, Dann Corbit wrote:
>
>>On February 15, 2004 at 13:24:54, Uri Blass wrote:
>>
>>>I understood from the winboard forum that Bob considers DanChess as a crafty
>>>clone and the question is what is the definition of a clone.
>>>
>>>I remember from slater's post in this forum that if most of the code is
>>>different you cannot win in court by complaining that it is a clone.
>>>
>>>I understood from Dann's post that only 30% of the code of DanChess is
>>>similiar(that does not mean the same as Crafty).
>>>
>>>Dann Corbit posted in the winboard forum the SEE function of Danchess that is
>>>similiar to Crafty.
>>>I wonder if it is really the main reason that Bob considers Danchess as a clone
>>>or only one of the reasons.
>>
>>There are more reasons that that one routine.  Several routines are similar.  He
>>also used some ideas from eval that are found only in crafty.  For instance, he
>>had a stonewall detection.  The only other program I ever saw with stonewall
>>detection was crafty.
>>
>>There is no standard for:
>>"This is a clone"
>>or
>>"This is not a clone"
>
>I believe that there are some standards.
>
>Suppose that a strong program with the same similiarity to Crafty becomes
>commercial and the author does not hide the similiarity and even share the
>similiar code that it has to crafty.
>
>I believe based on your descreption that if Hyatt go to court and sue the
>programmer then it is clear that the court is going to decide against him.
>
>>
>>It is clear to me that if you use ideas from someone else and they challenge you
>>as to cloning, then you may have a big problem to sort it out.
>
>I use alphabeta
>I use null move
>
>What other people can do against me?


This is called a "strawman" argument.  Nobody is claiming that or arguing from
that perspective.  The point here is _source code_.  Do you think it ok to
borrow a chapter from a book, change the main character's name, and sell it as
your own?  Copyright law does _not_ say it is ok.  Nor is it ok to take
thousands of lines of code from Crafty, change a few variable names, and then
call it a new program.

I think it is great if someone looks at the source, reads the comments, gets
some ideas they like and implement them.  Much of the _original_ Crafty design
came right from the "Chess Skill in Man and Machine" book chapter on chess 4.0.
But I copied _no_ source since none was given.  Ideas are ok to copy.  But _not_
thousands of lines of source.

That is the point here, it keeps getting lost in all the minutia...





>
>
>
>  Therefore, if
>>someone has an idea you want to use, I think the only wise course is to send an
>>email and ask if you can use the idea.
>
>I think that it is absurd.

I think both of you are absurd here, because you are arguing a point of view
that nobody holds.  If you can't see the difference between copying an idea and
copying an actual source program, perhaps there is nothing more to say?





>
>Do I need to ask people if I am allowed to use null move pruning?
>What in case that I think independtly about an idea that other people use in
>their soutce code and I did not read the source code?
>
>
>Uri



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