Hi there, On Thu, 5 Jul 2001, Wolfgang Abele wrote:
can you tell me what's the current situation regarding polynomial factorization in GiNaC? According to your wishlist, it's still missing, but I've just read some mails in this list saying that some people are working on the task.
Not that I knew of...
I'm a student of mathematics, and my diploma thesis is about polynomial factorization. I'm interested in both factorization in Z[x] and algebraic extensions, and I wonder if I could implement some algorithms or contribute to any ongoing projects.
Factorization in Z[x] is something that would be somewhat outside the normal GiNaC usage. As you have already found out there is no support for univariate polynomials over, say, Z. The reason for this is threefold: 1) for our physics applications here this is uninteresting, 2) we needed the more general expressions anyways and 3) implementation-wise this is the more trivial case anyway and already cleanly implemented in other libraries, CLN for instance. However, factorization in GiNaC would become really interesting as soon as one considers all the lifting up to multivariate polynomials over Z (and maybe algebraic extensions but I think these are not the main difficulty). If this is in any way tractable, I would suggest not investing too much time into factorization over Zp[x] by maybe implementing this in CLN -- which by the way would be a good place for factorization. Instead, maybe what should be done is use Victor Shoup's GPL'ed library NTL which seems to be the powerhorse in this field. But then again, I am not an expert in this field and would be glad to be convinced otherwise. Suggestions?
By the way, I've found out how to declare a polynomial ring over modular integers in CLN, so I don't need an example any more.
Cool! Regards -richy. -- Richard Kreckel <Richard.Kreckel@Uni-Mainz.DE> <http://wwwthep.physik.uni-mainz.de/~kreckel/>