NAME:
RZToverticalPotential
PURPOSE:
convert a RZPotential to a vertical potential at a given R
INPUT:
RZPot - RZPotential instance or list of such instances
R - Galactocentric radius at which to evaluate the vertical potential
OUTPUT:
(list of) linearPotential instance(s)
HISTORY:
2010-07-21 - Written - Bovy (NYU)