Fixed database typo and removed unnecessary class identifier.

venv/Lib/site-packages/scipy/special/_ellip_harm.py

@@ -0,0 +1,207 @@
+import numpy as np
+
+from ._ufuncs import _ellip_harm
+from ._ellip_harm_2 import _ellipsoid, _ellipsoid_norm
+
+
+def ellip_harm(h2, k2, n, p, s, signm=1, signn=1):
+    r"""
+    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:
+
+    >>> 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)
+
+    """
+    return _ellip_harm(h2, k2, n, p, s, signm, signn)
+
+
+_ellip_harm_2_vec = np.vectorize(_ellipsoid, otypes='d')
+
+
+def ellip_harm_2(h2, k2, n, p, s):
+    r"""
+    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
+
+    """
+    with np.errstate(all='ignore'):
+        return _ellip_harm_2_vec(h2, k2, n, p, s)
+
+
+def _ellip_normal_vec(h2, k2, n, p):
+    return _ellipsoid_norm(h2, k2, n, p)
+
+
+_ellip_normal_vec = np.vectorize(_ellip_normal_vec, otypes='d')
+
+
+def ellip_normal(h2, k2, n, p):
+    r"""
+    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
+
+    """
+    with np.errstate(all='ignore'):
+        return _ellip_normal_vec(h2, k2, n, p)