galpy.potential.dvcircdR

galpy.potential.dvcircdR(Pot, R, phi=None)

NAME:

dvcircdR

PURPOSE:

calculate the derivative of the circular velocity wrt R at R in potential Pot

INPUT:

Pot - Potential instance or list of such instances

R - Galactocentric radius (can be Quantity)

phi= (None) azimuth to use for non-axisymmetric potentials

OUTPUT:

derivative of the circular rotation velocity wrt R

HISTORY:

2013-01-08 - Written - Bovy (IAS)

2016-06-28 - Added phi= keyword for non-axisymmetric potential - Bovy (UofT)