Author: Robert Hyatt
Date: 06:50:14 08/24/04
Go up one level in this thread
On August 24, 2004 at 02:57:41, Uri Blass wrote: >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. > >I agree that having the same NextMove() is wrong but I think that you do not >expect people never to read the source of Crafty and learn from it so even if >people do not copy Crafty they cannot claim that they wrote their programs >independently. > >I guess that there are also small functions that a lot of people copy like >function to count the number of 1 in bitboard or to find the first 1. > >Uri I have looked at other programs. In 1970 Ed Kozdrowicki gave me the source to the Coko chess program. Slate gave me the source to chess 4.something in the late 70's. I learned a few things from both of those, without copying complete modules. IE my first SEE, used the current minimax approach in crafty, but came from code in Coko. I directly borrowed that 10 lines after talking to Ed about it. The other 200+ lines were different as we used different board representations, and different incremental updated information. I could even see someone borrowing the entire Swap() procedure (SEE). But going further to borrow the source for NextMove(), GenerateMoves(), Evaluate(), and so forth is going beyond "borrowing ideas or snippets"...
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