> Another difficulty I have is, how does one give attribution when the > code you write is heavily based on code by someone else (where their > code *IS* GPL'd), but your code has been rewritten to the point where > you can't just put their copyright notice on the code? > > There is an example of this in a very small section of my quadratic > sieve. I rewrote and made use of some (but certainly not all) of the > F2Matrix code used in Pari (and made it 20 times faster on some > architectures). It is still recognizable, but virtually no line is > precisely the same as used in Pari. Any ideas how I properly attribute > this? I've tried contacting the original copyright holder, but didn't > yet get a response.
That seems like an incredibly easy question. Just put the paragraph you just wrote above (with slight modification) at the top of the file. It's just like writing a research paper -- you have an acknowledgements section. > A similar issue is likely to arise for portions of the NTL replacement > library I am writing. There I can just contact Victor Shoup and see > what he wants me to do to properly credit him. > > Some portions of the code are so similar (virtually just translated) > that it might be appropriate to just make them copyright Victor Shoup > and note that I had made contributions!! Other parts are of course > uniquely mine. Even a slightly modified version would be copyright both of you. > P.S: Unfortunately msieve itself is (currently) only fast on an Athlon > machine and is otherwise not portable due to the use of assembly > language (if I understand correctly), so we can't just use it in SAGE > for factoring (it's about 8 times faster on an Athlon than the current > factoring implementation). > > Jason P's license restrictions are actually compatible with the GPL I > suspect, so this would be theoretically possible, if it weren't for his > home brew MP library. Incidentaly -- I'm really looking forward to fully integrating your quadratic sieve into SAGE, but I haven't yet, since I have to implement all other other stuff you asked for first :-). William --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
