I wonder if the category infrastructure would support a pervasive command like
R=IntegerModRing(7) R.promote(Fields(), with_check=True) R.category() Category of fields with the construction doing no extra work, and the promote method having defaults and exceptions consistent with John and Nick's "explicit is better" philosophy? I had though about is_field doing the upgrade, but I think these sort of side-effects are confusing. Rob On Mar 20, 10:07 am, Nick Alexander <ncalexan...@gmail.com> wrote: > On 20-Mar-10, at 8:50 AM, John Cremona wrote: > > > I would say that you should never test for primality unless > > specifically required, e.g. if the user asks is_field() (after which > > the category could be upgraded? I don't know if that is possible). > > > I would always use GF(p) rather than IntegerMod(p) for when I know p > > is prime. it is is vital in teaching primality tests and the like > > that one can form IntegerModRing(n) without knowing (or automatically > > testing behind the scenes) whether or not n is prime. > > > There are surely many other similar situations, for example when > > constructing a commutative ring it might be expensive to determine > > whether or not it is an Integral Domain. > > +1, I agree with John: no primality testing unless I ask for it, and > even then I would like to be able to specify the category and override > it. > > Nick -- 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 To unsubscribe from this group, send email to sage-devel+unsubscribegooglegroups.com or reply to this email with the words "REMOVE ME" as the subject.
