Le mercredi 12 mars 2014 15:57:00 UTC+1, Nicolas M. Thiéry a écrit : > > On Wed, Mar 12, 2014 at 06:41:07AM -0700, Eric Gourgoulhon wrote: > > In order to treat tensor fields on a parallelizable domain N of some > > smooth manifold as elements of a free module (cf. #15916 and this > post), > > one has first to introduce the commutative ring C^oo(N) of smooth > > functions N --> R, as a new class, ScalarFieldRing say. Browsing > through > > Sage reference manual, a natural guess would be to make it a subclass > of > > CommutativeRing: > > You don't necessarily need too. You could also just inherit from > Parent; the important thing is to set the category to > CommutativeRings(). >
You mean the third solution is the one to use ? > > CommutativeRing is a bit of a legacy stuff: it's still there because > some features have not yet been moved to categories, and also because > some parents where pure arithmetic speed on elements is vital > (e.g. small finite fields), need it to by Cython. > Thanks for these explanations. Regards, Eric. > > Cheers, > Nicolas > -- > Nicolas M. Thiéry "Isil" <nth...@users.sf.net <javascript:>> > http://Nicolas.Thiery.name/ > -- 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. For more options, visit https://groups.google.com/d/optout.
