galpy.potential.Potential.phi2deriv

Potential.phi2deriv(R, Z, phi=0.0, t=0.0)

NAME:

phi2deriv

PURPOSE:

evaluate the second azimuthal derivative

INPUT:

R - Galactocentric radius

Z - vertical height

phi - Galactocentric azimuth

t - time

OUTPUT:

d2Phi/dphi2

HISTORY:

2013-09-24 - Written - Bovy (IAS)