gradient¶
-
biff.scf.
gradient
(xyz, Snlm, Tnlm, G=1, M=1, r_s=1)¶ Compute the gradient of the gravitational potential of the basis function expansion at a set of positions given the expansion coefficients.
Parameters: xyz :
ndarray
A 2D array of positions where
axis=0
are multiple positions andaxis=1
are the coordinate dimensions (x, y, z).Snlm :
ndarray
A 3D array of expansion coefficients for the cosine terms of the expansion. This notation follows Lowing et al. (2011). The array should have shape
(nmax+1,lmax+1,lmax+1)
and any invalid terms (e.g., when m > l) will be ignored.Tnlm :
ndarray
A 3D array of expansion coefficients for the sine terms of the expansion. This notation follows Lowing et al. (2011). The array should have shape
(nmax+1,lmax+1,lmax+1)
and any invalid terms (e.g., when m > l) will be ignored.G : numeric (optional)
Gravitational constant. Leave unset for dimensionless units.
M : numeric (optional)
Mass scale. Leave unset for dimensionless units.
r_s : numeric (optional)
Length scale. Leave unset for dimensionless units.
Returns: grad :
ndarray
A 2D array of the gradient of the potential at each input position. Will have the same shape as the input position array,
xyz
.