On 19 mai, 12:34, Volker Braun <vbraun.n...@gmail.com> wrote: > For starters, most of the plotting stuff will rely on quickly computing > numerical approximations to symbolic expressions. There you certainly don't > want to start refining the RIF precision iteratively if you hit a > numerically unstable point.
I got it but it would be still prefarable to use RIF in doing plots rather than plotting something False. More seriously, I do make a difference between making an evaluation of a function (ie computation of cos(x) for some given approximate real number x) and a conversion of a constant (ie the conversion of (106*pi - 333) / (355 - 113*pi) to an approximate field). In particular, when I write ((106*pi - 333) / (355 - 113*pi)).n(digits=4) I do expect the four first digits of my real number and not a "ValueError: power::eval(): division by zero". Even if I am a starter. > The only bug that I see is that the documentation of n() could be improved > to explain that input precision =! output precision for symbolic > expressions. But then thats pretty obvious. It is not obvious as you do not get in the answer how much digits are correct (claiming that they are different is not interesting nor meaningful). Moreover, it is not only about symbolic expression as it fails for number field elements. Vincent -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
