Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Is IsiChess a Crafty clone ?

Author: Gerd Isenberg

Date: 23:17:49 08/23/04

Go up one level in this thread


On August 23, 2004 at 23:45:00, Robert Hyatt wrote:

>On August 23, 2004 at 20:29:15, Gerd Isenberg wrote:
>
>>On August 23, 2004 at 17:41:38, Matthias Gemuh wrote:
>>
>>>
>>>
>>>>
>>>>Such "standard" code like NextMove is IMHO not sufficent to proof El Chinito as
>>>>Crafty clone. Did i missed something?
>>>>
>>>>BTW. Is it legal to disassembly others executables?
>>>>
>>>
>>>
>>>
>>>Hi Gerd,
>>>Is "such standard code like NextMove" also implemented the same way in your
>>>engine, IsiChess ? Are the Crafty evaluation functions in ElChinito also
>>>standard and in IsiChess ? Are the reported Crafty bugs in ElChinito also
>>>standard and present in IsiChess ?
>>
>>That IsiChess has a complete other movegen does not proof, that El Chinitos
>>getMove is a copy of Crafty, even if it is likely, due to the other point with
>>eval and the 99999 compare.
>>
>>I admit that i copied some source code here from CCC via clipboard into my
>>program, for instance kogge-stone algorithms. The same might be true for others,
>>and the intention i and others post source-code here is to share it and to get a
>>feedback, improvements and other ideas.
>>
>>Is Crafty's getMove-code really so unique and some code snippets got never
>>posted here? If i implement some quicksort from some published pseudo code, it
>>is not unlikely that i get the same assembly, despite other identifiers.
>
>That's a poor argument, often tried on me by students.  It doesn't fly.  A
>bubblesort or quicksort or heapsort written by two different people might look
>the same for bubblesort (10 lines of code) but _definitely_ not for quick/heap
>sort.  NextMove() is over 250 lines of code.  The chances of two people writing
>two programs independently, and having them produce the _same_ assembly, is so
>close to zero that IEEE FP would store it as zero.

Ok, i was totally wrong.
My apologies.

Gerd


>
>It really is a vanishingly small probability.  So, beyond a doubt, things were
>copied.  How much is unknown at present.  But it looks to be a large part of the
>"chess kernel".  IE evaluate, move generation and selection, and who knows what
>else at present.  Numbering the bits backward for the PC.  Copying useless bits
>of code that do nothing except wave a red flag.  All of this looks suspect.
>We'll see whether it has an explanation that is believable or not.
>
>
>>
>>
>>>You create the impression that the ElChinito guy is the one doing the right
>>>thing and Paul H. is rightly to be blamed for his catch-cloner efforts.
>>>Sorry, but I don't share your strange opinion.
>>
>>
>>For what reason does one disassembly other chess programs?
>>Was there a beginning suspicion with El Chinito?
>>
>>Gerd
>
>
>Probably "curiosity".  Same thing that led people to ask me to investigate Le
>Petite and Voyager a few years back...
>
>
>
>
>
>>
>>>
>>>Matthias.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.