I repeat, The interesting cases are obvious those which are not covered.
I don't know what your fix is, nor do I especially care, but I gather that, now, at least your "stable" word is meant to indicate something like a small bound in the maximum over all coefficients of the difference in relative error between the true result and the computed result. I have no reason to believe this is an especially relevant measure, since some coefficients (especially the first and the last) are probably far more important and, incidentally, far easier to compute. Here are some more cases. p= (x+1)*(sum(x^i,i,1,n) q= (x-1)*sum((-1)^i*x^i,i,1,n) pick large n. p and q each have n+1 terms. p*q has 4 non-zero terms, I think. Though perhaps this is testing the same issue. Here is another p=1.7976931348623157E308; q= 10*x What do you do when the coefficients overflow? You might also try arithmetic using the classic product((x-i),i,1,n). RJF -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
