Personally I believe that one should only use a vector type (class) when one wants to do something vectorial with the object, i.e. add two or take a scalar multiple (and so on). If you just need a list, use a list. The trouble comes when people think of anything enclosed in some shape of brackets with components separated by commas as being a "vector".
Surely using lists which are pure Python is much more efficient than using vectors which are more complicated, so should only be used where necessary. But that's just my opinion. Of course this no way contradicts the need to implement functions in such a way as they can take vector input where sensible, as in the lcm(vector-of-integers) example which came up recently on sage-support. John 2008/5/8 Marshall Hampton <[EMAIL PROTECTED]>: > > This is somewhat tangential but related: when writing polytope code, > I decided that vertices would be returned as lists, rather than > vectors, precisely because of this sort of issue. Currently the > lattice polytopes have vertices that are vectors, so things are a bit > inconsistent. > > Anyway, it would be nice for vectors to be better supported, but it > seems like a difficult task to me - getting things like scipy/numpy to > play nice with them, for example, seems tough. > > -M. Hampton > > > > On May 8, 8:06 am, Jason Grout <[EMAIL PROTECTED]> wrote: > > John Cremona wrote: > > > This works instead: > > > > > parametric_plot([exp(-t)*e for e in evec],1,2) > > > > > where it's fine to replace evec by [1,2] (no need for vector([1,2]). > > > > > I think the problem is that exp(-t) * evec is a *vector* of functions > > > when a *list* of function is what the plot wants. > > > > If that is the case, then you should be able to do list(exp(-t)*evec) to > > get a list of the components of the vector. > > > > Jason > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
