Is it recomputing a Grobner basis for the new ideal? That could be slow. John
On 04/11/2007, Simon King <[EMAIL PROTECTED]> wrote: > > Dear sage-support team, > > i have a question on how to do a very simple singular operation (via > the interface) in the quickest way. > > Suppose you have an ideal I and a polynomial p. What is the quickest > way to append p to I? > > In pure Singular, you could do > I = I,p > but this is not very good. If one knows sz = ncols(I), > I[sz+1] = p > is faster. > > Now i did similar things with the Sage Singular interface. I have a > ring of moderate size (char. 5, about 20 variables named c_m_n for > integers m,n, with a weighted degree order), and I know the size sz of > the ideal I, which is moderate as well (about 200 polynomials). The > polynomial p is > c_6_9^2+c_6_11^2+c_6_10*c_6_12+c_6_11*c_6_12+c_6_11*c_6_13+ > c_6_12*c_6_13+c_6_10*c_6_14+c_6_12*c_6_14, > so, again, not exactly huge. > > However, it takes more than 15 minutes (!!) to append p to I, if i do > singular.eval( I.name()+'[%d]' = '%(sz)+p.name()) > > I guess saying > I[sz] = p > would do essentially the same, wouldn't it? > > I can not believe that such a simple operation in such a small setting > takes such a long time. > > How can i do better? > > Yours sincerely > Simon > > > > > -- John Cremona --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
