On 2012-11-13, Nils Bruin <nbr...@sfu.ca> wrote: > On Nov 12, 6:06 pm, Dima Pasechnik <dimp...@gmail.com> wrote: >> sage: e.cremona_label() >> '457532830151317a1' >> sage: e.analytic_rank(leading_coefficient=True) >> (4, -2.50337480324368498e-9) >> >> here is what I got after some hours of running. >> e-9 does not look as suspiciosuly small to me... > > That depends on what the bounds on the error in that number are. If > it's > -2.5e-9 +- 1e-3 > then it can very well be an approximation to 0 (which we know it is). > It's the accuracy of the approximation that matters--not its size.
looking at the slide 22 of http://homepages.warwick.ac.uk/~masgaj/papers/bsd50.pdf seems to tell that we are not talking about a guaranteed computation, but just about a heuristic, no more than that. Unless I miss something. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To post to this group, send email to sage-devel@googlegroups.com. To unsubscribe from this group, send email to sage-devel+unsubscr...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en.
