Maybe, but the coefficients are symbolic non-polynomial (and non- rational) expressions. Can it be done anyway? I also had problems with subtracting 1 from an expression, which I got by substituting rational functions into a polynomial, so I switched to symbolic representation.
On May 22, 12:54 pm, Robert Bradshaw <[EMAIL PROTECTED]> wrote: > It almost sounds to me like you'd rather be working in a multivariate > polynomial ring (which will be much, much faster). > > - Robert > > On May 22, 2008, at 12:48 PM, Andrey Novoseltsev wrote: > > > > > Actually, yesterday was the first time I really tried to use Sage for > > symbolic computations and it was quite frustrating for me. > > > 1) It would be really nice if it was faster. > > > 2) It seems to me that > > ((x+y)*y).coeff(y^2) > > and > > ((x+y)*y).expand().coeff(y^2) > > should return the same coefficient 1 (while the first one returns > > zero). > > > 3) I think that > > ((x+x*y)/x).simplify() > > should return 1+y, instead of the original expression, otherwise, what > > is simplify simplifying? > > > 4) It would be nice to be able to get the part of given degree in the > > given list of variables, and write > > f3 = fp.homogeneous_part([up, vp], 3) > > instead of something like > > f3 = (fp.coeff(up,3).coeff(vp,0)*up^3*vp^0 > > + fp.coeff(up,2).coeff(vp,1)*up^2*vp^1 > > + fp.coeff(up,1).coeff(vp,2)*up^1*vp^2 > > + fp.coeff(up,0).coeff(vp,3)*up^0*vp^3)- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com 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://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
