On Monday, August 1, 2016 at 2:19:32 AM UTC-7, Nicolas M. Thiéry wrote: > > Hi John, > > On Thu, Jul 28, 2016 at 02:17:15PM -0700, John H Palmieri wrote: > > When defining a category in Sage, is there any way to define > > "HomsetMethods" for that category? For example, if I want to have > > certain morphisms only defined when in an endomorphism set (so tab > > completion is less misleading), I would like to do: > > class MyCategory(Category_singleton): > > blah > > class Endset(CategoryWithAxiom): > > class HomsetMethods: > > def some_map(self): > > """ > > This is a map which should only exist in a set of > > endomorphisms. > > """ > > Is this possible? > > If you want to implement methods that apply to all morphisms in all > subcategories, you can do: > > class MyCategory(Category_singleton): > class MorphismMethods: > def f(x): ... > > If you want to implement methods that apply to all endomorphisms in > all *full* subcategories (literally: elements of some homset in > MyCategory that is a endset): > > class MyCategory(Category_singleton): > class Homsets(HomsetsCategory): > class EndSet(CategoryWithAxiom): > class ElementMethods: > def f(x): ... >
Good, this approach does what I want. Thank you. > > At this stage, I don't see a way to provide a method in all > subcategories, but only for endomorphisms. How important is this use > case? > I don't need that for my case. -- John > It's annoying to have to create the Homsets class above, if the only > thing there is inside is about Endset. Maybe we could have a Endsets > shortcut. > > Sorry, this is all a bit complicated. Some of it is because the math > behind is not trivial: no free lunch. But it maybe as well that we > haven't yet accumulated enough experience with support for homsets / > morphisms to get to the right design. Ideas welcome! > > Ah, just in case this helps reducing the number of experiments: as its > name suggests, XXXMethods never contains anything else than methods > (and possibly constants). > > 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
