Wrapped Cauchy distribution

The probability density function for wrapped Cauchy distribution is:

.. math::

f(x, k) = \frac{1-k^2}{2\pi (1+k^2 - 2k \cos(x))}

for :math:0 \le x \le 2\pi, 0 < k < 1.

The following plots show the pdf and cdf:

.. image:: ../../../../tests/imgs/stats/continuous/wrapcauchy/wrapcauchypdf.png :align: center :width: 480

.. image:: ../../../../tests/imgs/stats/continuous/wrapcauchy/wrapcauchycdf.png :align: center :width: 480