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


pos - positions of particles in rectangular coordinates with shape [3,n]

N - size of the Nth dimension of the expansion coefficients

mass= (1.) mass of particles (scalar or array with size n)

a= (1.) parameter used to scale the radius


(Acos,Asin) - Expansion coefficients for density dens that can be given to SCFPotential.__init__


2020-11-18 - Written - Morgan Bennett (UofT)

2021-02-22 - Sped-up - Bovy (UofT)