U Hv f@sfddlZddlmZddlmZmZdddZejeddZ d d Z d d Z eje ddZ d dZ dS)N _ellip_harm) _ellipsoid_ellipsoid_normcCst|||||||S)aN Ellipsoidal harmonic functions E^p_n(l) These are also known as Lame functions of the first kind, and are solutions to the Lame equation: .. math:: (s^2 - h^2)(s^2 - k^2)E''(s) + s(2s^2 - h^2 - k^2)E'(s) + (a - q s^2)E(s) = 0 where :math:`q = (n+1)n` and :math:`a` is the eigenvalue (not returned) corresponding to the solutions. Parameters ---------- h2 : float ``h**2`` k2 : float ``k**2``; should be larger than ``h**2`` n : int Degree s : float Coordinate p : int Order, can range between [1,2n+1] signm : {1, -1}, optional Sign of prefactor of functions. Can be +/-1. See Notes. signn : {1, -1}, optional Sign of prefactor of functions. Can be +/-1. See Notes. Returns ------- E : float the harmonic :math:`E^p_n(s)` See Also -------- ellip_harm_2, ellip_normal Notes ----- The geometric interpretation of the ellipsoidal functions is explained in [2]_, [3]_, [4]_. The `signm` and `signn` arguments control the sign of prefactors for functions according to their type:: K : +1 L : signm M : signn N : signm*signn .. versionadded:: 0.15.0 References ---------- .. [1] Digital Library of Mathematical Functions 29.12 https://dlmf.nist.gov/29.12 .. [2] Bardhan and Knepley, "Computational science and re-discovery: open-source implementations of ellipsoidal harmonics for problems in potential theory", Comput. Sci. Disc. 5, 014006 (2012) :doi:`10.1088/1749-4699/5/1/014006`. .. [3] David J.and Dechambre P, "Computation of Ellipsoidal Gravity Field Harmonics for small solar system bodies" pp. 30-36, 2000 .. [4] George Dassios, "Ellipsoidal Harmonics: Theory and Applications" pp. 418, 2012 Examples -------- >>> from scipy.special import ellip_harm >>> w = ellip_harm(5,8,1,1,2.5) >>> w 2.5 Check that the functions indeed are solutions to the Lame equation: >>> import numpy as np >>> from scipy.interpolate import UnivariateSpline >>> def eigenvalue(f, df, ddf): ... r = ((s**2 - h**2)*(s**2 - k**2)*ddf + s*(2*s**2 - h**2 - k**2)*df - n*(n+1)*s**2*f)/f ... return -r.mean(), r.std() >>> s = np.linspace(0.1, 10, 200) >>> k, h, n, p = 8.0, 2.2, 3, 2 >>> E = ellip_harm(h**2, k**2, n, p, s) >>> E_spl = UnivariateSpline(s, E) >>> a, a_err = eigenvalue(E_spl(s), E_spl(s,1), E_spl(s,2)) >>> a, a_err (583.44366156701483, 6.4580890640310646e-11) r)h2k2npsZsignmZsignnr =/tmp/pip-unpacked-wheel-96ln3f52/scipy/special/_ellip_harm.py ellip_harmsYrd)Zotypesc Cs4tjddt|||||W5QRSQRXdS)an Ellipsoidal harmonic functions F^p_n(l) These are also known as Lame functions of the second kind, and are solutions to the Lame equation: .. math:: (s^2 - h^2)(s^2 - k^2)F''(s) + s(2s^2 - h^2 - k^2)F'(s) + (a - q s^2)F(s) = 0 where :math:`q = (n+1)n` and :math:`a` is the eigenvalue (not returned) corresponding to the solutions. Parameters ---------- h2 : float ``h**2`` k2 : float ``k**2``; should be larger than ``h**2`` n : int Degree. p : int Order, can range between [1,2n+1]. s : float Coordinate Returns ------- F : float The harmonic :math:`F^p_n(s)` Notes ----- Lame functions of the second kind are related to the functions of the first kind: .. math:: F^p_n(s)=(2n + 1)E^p_n(s)\int_{0}^{1/s}\frac{du}{(E^p_n(1/u))^2\sqrt{(1-u^2k^2)(1-u^2h^2)}} .. versionadded:: 0.15.0 See Also -------- ellip_harm, ellip_normal Examples -------- >>> from scipy.special import ellip_harm_2 >>> w = ellip_harm_2(5,8,2,1,10) >>> w 0.00108056853382 ignoreallN)nperrstate_ellip_harm_2_vec)rrr r r r r r ellip_harm_2fs4rcCst||||S)N)rrrr r r r r _ellip_normal_vecsrc Cs2tjddt||||W5QRSQRXdS)a$ Ellipsoidal harmonic normalization constants gamma^p_n The normalization constant is defined as .. math:: \gamma^p_n=8\int_{0}^{h}dx\int_{h}^{k}dy\frac{(y^2-x^2)(E^p_n(y)E^p_n(x))^2}{\sqrt((k^2-y^2)(y^2-h^2)(h^2-x^2)(k^2-x^2)} Parameters ---------- h2 : float ``h**2`` k2 : float ``k**2``; should be larger than ``h**2`` n : int Degree. p : int Order, can range between [1,2n+1]. Returns ------- gamma : float The normalization constant :math:`\gamma^p_n` See Also -------- ellip_harm, ellip_harm_2 Notes ----- .. versionadded:: 0.15.0 Examples -------- >>> from scipy.special import ellip_normal >>> w = ellip_normal(5,8,3,7) >>> w 1723.38796997 rrN)rrrrr r r ellip_normals*r)rr) ZnumpyrZ_ufuncsrZ _ellip_harm_2rrrZ vectorizerrrrr r r r s  \8