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Subject: Re: definition of clones: Danchess an Crafty

Author: Dann Corbit

Date: 11:45:36 02/15/04

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On February 15, 2004 at 14:36:56, Robert Hyatt wrote:

>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?

I think that it is an honest difference of opinion.  I also do see where you are
coming from.  I also understand your frustration at many of the blatant crafty
rip-offs.  It makes perfect sense to me for you to put your foot down and holler
"ENOUGH IS ENOUGH!"

But I think Daniel Shawul may be bearing the brunt of the mistakes of others.
In any case, we all agree that it was a terrible oversight not to mention the
use of crafty ideas in his program.  He is doing a complete rewrite to 0x88 (and
in fact has already accomplished it).  So I think it would be nice to let
bygones be bygones and forget the whole matter.

I still have great respect for all of the parties involved and I think it would
be nice to have everyone forgive all of the others.


>>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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