galpy.potential.Potential.phi2deriv¶
- Potential.phi2deriv(R, z, phi=0.0, t=0.0)[source]¶
NAME:
phi2deriv
PURPOSE:
evaluate the second azimuthal derivative
INPUT:
R - Galactocentric radius (can be Quantity)
Z - vertical height (can be Quantity)
phi - Galactocentric azimuth (can be Quantity)
t - time (can be Quantity)
OUTPUT:
d2Phi/dphi2
HISTORY:
2013-09-24 - Written - Bovy (IAS)