NAME:
__call__
PURPOSE:
evaluate the potential
INPUT:
R - Cylindrica radius
phi= azimuth (optional)
t= time (optional)
dR=, dphi= if set to non-zero integers, return the dR,dphi’t derivative
OUTPUT:
Phi(R(,phi,t)))
HISTORY:
2010-07-13 - Written - Bovy (NYU)