Added the support of convex indicator for feasible sets bounded by a radius

[ErwanMeunier]

I added and documented the support of convex indicator for radiali bounded feasible sets. The way I added the support allows to add diameter and radius constraints simultaneously. I don't know if it is a good thing or not from the POV of maintainers.

Cheers,
Erwan

[AdrienTaylor]

Hello @ErwanMeunier !

Thanks for the update :) Just a quick comment: I think it makes sense to add a new point and to center the radius condition at this point (so that the set is not necessarily centered at 0).

About our POV: we implemented it several times (but did not update it here) as radius-type conditions are sometimes more convenient than diameter-type ones. So thanks a lot for the effort!

Cheers,

[ErwanMeunier]

Hello @AdrienTaylor,

I've committed an updated version based on your feedback. In summary, there are now two options for the radius conditions:

1. If the user specifies a center for ConvexIndicatorFunction(.), the conditions are defined around this point.
2. If no center is provided (center=None), the origin is assumed to be the center of the feasible set.

Let me know if there's anything further I can refine. 😉

Cheers,
Erwan

[AdrienTaylor]

Todo @bgoujaud @AdrienTaylor

• redefine the way the radius is set with fewer "tests" (redecompose the if's) -> follow the previous lines that were done for the diameter. Essentially, we can accept that both a radius and a diameter are set.
• add tests!

[bgoujaud]

Thanks a lot for the PR!

It sounds good to me.
I made a mild update in #118 concerning the if statement and added a quick test of the new feature.