[Numpy-discussion] failure to register ufunc loops for user defined types

[David Cournapeau]

On Sun, Dec 4, 2011 at 9:45 PM, Charles R Harris
<charlesr.harris at gmail.com> wrote:

>
> We'll see how much interest there is. If it becomes official you may get
> more feedback on features. There are some advantages to having some user
> types in numpy. One is that otherwise they tend to get lost, another is that
> having a working example or two provides a templates for others to work
> from, and finally they provide test material. Because official user types
> aren't assigned anywhere there might also be some conflicts. Maybe something
> like an extension types module would be a way around that. In any case, I
> think both rational numbers and quaternions would be useful to have and I
> hope there is some discussion of how to do that.

I agree that those will be useful, but I am worried about adding more
stuff in multiarray. User-types should really be separated from
multiarray. Ideally, they should be plugins but separated from
multiarray would be a good first step.

I realize it is a bit unfair to have this ready for Geoffray's code
changes, but depending on the timelines for the 2.0.0 milestone, I
think this would be a useful thing to have. Otherwise, if some ABI/API
changes are needed after 2.0, we will be dragged down with this for
years. I am willing to spend time on this. Geoffray, does this sound
acceptable to you ?

David