[REQUEST] Spherically-averaged atomic densities and derivatives

[PaulWAyers]

Is your feature request related to a problem? Please describe. The goal is to be able to evaluate the spherically-averaged density, its derivatives, and the kinetic-energy density for an atom.

Is there a specific integral/formula that you would like implemented? There are several possible ways to do this, including using fractional occupation numbers or (probably easier) neglecting the spherical harmonic contribution when evaluating the density and its derivatives.

Is there a change to the code or algorithm you would like to see? This might be a different set of routines for spherically averaging or maybe it is a flag for existing routines.