On Friday, 4 November 2016 13:50:55 UTC+1, Jeroen Demeyer wrote: > > On 2016-11-04 13:41, 'Bill Hart' via sage-devel wrote: > > Sorry just 1s after posting this, I remembered Pari doesn't have > > multivariate factoring. > > PARI doesn't really have multivariate polynomials in the first place > (they do have polynomials with polynomial coefficients). And they > certainly do not implement any non-trivial functionality for such > polynomials. >
Yeah, they use a recursive structure for multivariates. But this isn't necessarily a problem. Some GCD algorithms for example, essentially work variable by variable. They really aren't possible to implement using a distributed representation or arbitrary orderings, so you have to convert to a recursive representation anyway. I haven't implemented any multivariate factorisation algorithms, so I can't say with confidence that the same is true for factorisation, but I suspect it is for some factorisation algorithms. Of course, even if you use a recursive representation, you probably want it to be sparse recursive, not dense, for many applications. I'm currently implementing a sparse recursive module in Julia after implementing a sparse distributed multivariate module. Unfortunately, there aren't a lot of good open source examples to follow, so I'm doing all of this by trial and error at present. Lots of trials and even more errors. Bill. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
