def von_mises(self, pars, x):
    '\n        Compute a simplified von Mises function.\n\n        Original formulation in Richard von Mises, "Wahrscheinlichkeitsrechnung\n        und ihre Anwendungen in der Statistik und theoretischen Physik", 1931,\n        Deuticke, Leipzig; see also Mardia, K.V. and Jupp, P.E., " Directional\n        Statistics", 1999, J. Wiley, p.36;\n        http://en.wikipedia.org/wiki/Von_Mises_distribution\n        The two differences are that this function is a continuous probability\n        distribution on a semi-circle, while von Mises is on the full circle,\n        and that the normalization factor, which is the inverse of the modified\n        Bessel function of first kind and 0 degree in the original, is here a fit parameter.\n        '
    (a, k, t) = pars
    return (a * np.exp((k * (np.cos((2 * (x - t))) - 1))))
Compute a simplified von Mises function.

Original formulation in Richard von Mises, "Wahrscheinlichkeitsrechnung
und ihre Anwendungen in der Statistik und theoretischen Physik", 1931,
Deuticke, Leipzig; see also Mardia, K.V. and Jupp, P.E., " Directional
Statistics", 1999, J. Wiley, p.36;
http://en.wikipedia.org/wiki/Von_Mises_distribution
The two differences are that this function is a continuous probability
distribution on a semi-circle, while von Mises is on the full circle,
and that the normalization factor, which is the inverse of the modified
Bessel function of first kind and 0 degree in the original, is here a fit parameter.
def von_mises(self, pars, x):
    '\n        Compute a simplified von Mises function.\n\n        Original formulation in Richard von Mises, "Wahrscheinlichkeitsrechnung\n        und ihre Anwendungen in der Statistik und theoretischen Physik", 1931,\n        Deuticke, Leipzig; see also Mardia, K.V. and Jupp, P.E., " Directional\n        Statistics", 1999, J. Wiley, p.36;\n        http://en.wikipedia.org/wiki/Von_Mises_distribution\n        The two differences are that this function is a continuous probability\n        distribution on a semi-circle, while von Mises is on the full circle,\n        and that the normalization factor, which is the inverse of the modified\n        Bessel function of first kind and 0 degree in the original, is here a fit parameter.\n        '
    (a, k, t) = pars
    return (a * np.exp((k * (np.cos((2 * (x - t))) - 1))))