Hi Christian, On Fri, 29 Jun 2012 00:10:32 -0700 (PDT) Christian Stump <christian.st...@gmail.com> wrote:
> I want to do some computations with multivariate polynomials in the group W > of type H4 (14400 elements). I have a summand for every element w \in W, > and a product of 4 polynomials in each summand: > > gens = [] > for obj in gens_objects: > p = 0 > for w in W: > mon_w = F[obj][w][0] * F[obj][w][1] * F[obj][w][2] * F[obj][w][3] > p = p + mon_w > gens.append(p) > return gens > > for every obj, this takes about 10sec (doing the same computation in Magma > is about 4 times faster), and almost all the time is spend in all these > multiplications (I also tried prod( F[obj][w] ) and P.prod( F[obj][w] ) > where P is a polynomial ring in 8 variables, but both were slower. So my > question is if I can somehow do the complete construction of such a > generator p somehow directly in singular, and then turn it into a Sage > object only before appending it to gens? Can you post a complete example, if possible including the Magma code that you compare with? Feel free to email me personally if the files are too big for the list. I doubt if the multivariate polynomial arithmetic is so much slower, the extra time could also be taken by all the lookups in F[obj][w][0]. In any case, constructing the polynomial directly in Singular should take the same time as doing it from Sage, since Sage uses Singular as a C-library. Cheers, Burcin -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org