MOCharges API Question?

Right now (or maybe it's still a WIP?) MOCharges returns a number of centers by number of MOs matrix. The centers used are the ones in from space of the MOs. This could conceivably not be what the caller wants because: e.g., the same center was added to the AO basis set multiple times, there are ghost atoms, and/or there are mid-bond functions. My proposal is:

• we introduce a class PointSet which is a container of Point objects (this would live in LibChemist)
• Refactor the Atom class to inherit from PointCharge (related to this issue)
• Ensure AOBasisSet and Molecule are implicitly convertible to PointSet
• Have MOCharges take a PointSet instance and a DerivedSpace instance

This allows the caller of MOCharges to specify the centers they care about.

Thoughts? Takers?

Edit: Also I propose the name MOPopulations since AFAIK this is simply counting the number of electrons at a point (the electronic charge would -2 times the matrix returned by this PT for restricted spatial orbitals).

Start by reviewing the current MOCharges API and how AOBasisSet, Molecule, Atom, and DerivedSpace are represented, then compare the proposed PointSet and Point abstractions with LibChemist. Confirm the intended PointCharge relationship and whether the API should be renamed MOPopulations. Done means callers can explicitly provide the centers and the behavior for repeated, ghost, and mid-bond functions is defined.