galpy.orbit.Orbit.SOS

Orbit.SOS(pot, ncross=500, surface=None, t0=0.0, method='dop853_c', skip=100, progressbar=True, numcores=2, force_map=False, **kwargs)

NAME:

SOS

PURPOSE:

calculate the surface of section of the orbit

INPUT:

pot - Potential or list of such instances

ncross= (500) number of times to cross the surface

surface= (None) surface to punch through (this has no effect in 3D, where the surface is always z=0, but in 2D it can be ‘x’ or ‘y’ for x=0 or y=0)

t0= (0.) time of the initial condition (can be a Quantity)

integration keyword arguments:

method = ‘odeint’ for scipy’s odeint

‘rk4_c’ for a 4th-order Runge-Kutta integrator in C ‘rk6_c’ for a 6-th order Runge-Kutta integrator in C ‘dopr54_c’ for a 5-4 Dormand-Prince integrator in C ‘dop853’ for a 8-5-3 Dormand-Prince integrator in Python ‘dop853_c’ for a 8-5-3 Dormand-Prince integrator in C

skip= (100) for non-adaptive integrators, the number of basic steps to take between crossings (these are further refined in the code, but only up to a maximum refinement, so you can use skip to get finer integration in cases where more accuracy is needed)

progressbar= (True) if True, display a tqdm progress bar when integrating multiple orbits (requires tqdm to be installed!)

numcores - number of cores to use for Python-based multiprocessing (pure Python or using force_map=True); default = OMP_NUM_THREADS

force_map= (False) if True, force use of Python-based multiprocessing (not recommended)

OUTPUT:

(R,vR) for 3D orbits, (y,vy) for 2D orbits when surface==’x’, (x,vx) for 2D orbits when surface==’y’

HISTORY:

2023-03-16 - Written - Bovy (UofT)