RdC wrote on 01/10/12 at 11:37:38:
There may be analogies to the book or article writing process. You are writing about a variation or position covered extensively and correctly by a previous author. To what extent is it legitimate to copy or paraphrase the previous analysis? Are you required to quote the previous source? Would it make a difference if you wee entering a competition for the "best" analysis.
The source code in question was covered by a license which essentially says:
1) if you use it just for yourself do whatever you want with it.
2) if you distribute it or programs based on it these programs *must* be covered by the same license and the modified source code *must* also be made available.
[edit: this is the license fruit used. Crafty's license is non-standard but prohibits taking the program in part or as a whole and entering tournaments (under a new name) without explicit permission from the authors]
Quote:From a practical user's point of view, you want the strongest chess engine and programmers griping about whether the program is "original" is a theological debate of little practical interest.
This is irrelevant. If I publish a chess book entitled The "Lativian Gambit still lives" which is just a copy of the original with a few corrections (this is just hypothetically speaking, we know of course none are needed) and publish it then the users might like the added value but I suspect the original author would have a problem with that (especially if I would deny that I copied the book but make lots of money from it).
Quote:The common ground appears to be that the Rybka team read the source code of Fruit and other programs and paraphrased the ideas.
The analysis of the disassembled code and the occurrence of identical bugs/identical illogical behaviour shows quite convincingly that source code must have been copied (as in cut and paste). If the ideas would have been reimplemented then identical bugs/illogical behaviour could not be observed.