galpy.potential.scf_compute_coeffs_spherical_nbody¶
This function is the equivalent to galpy.potential.scf_compute_coeffs_spherical but computing the coefficients based on an N-body representation of the density.
Note: This function computes Acos and Asin as defined in Hernquist & Ostriker (1992), except that we multiply Acos by 2 such that the density from Galpy’s Hernquist Potential corresponds to \(Acos = \delta_{0n}\delta_{0l}\delta_{0m}\).
Further note that this function is a specification of galpy.potential.scf_compute_coeffs_nbody where \(Acos_{nlm} = 0\) at \(l\neq0\)
- galpy.potential.scf_compute_coeffs_spherical_nbody(pos, N, mass=1.0, a=1.0)[source]¶
Numerically compute the expansion coefficients for a spherical expansion for a given $N$-body set of points
- Parameters:
pos (numpy.ndarray) – Positions of particles in rectangular coordinates with shape [3,n]
N (int) – Size of the Nth dimension of the expansion coefficients
mass (float or numpy.ndarray, optional) – Mass of particles (scalar or array with size n), by default 1.0
a (float, optional) – Parameter used to scale the radius, by default 1.0
- Returns:
Expansion coefficients for density dens that can be given to SCFPotential.__init__
- Return type:
tuple
Notes
2020-11-18 - Written - Morgan Bennett (UofT)
2021-02-22 - Sped-up - Bovy (UofT)