calc_k_squared
==============

.. py:function:: luminet.black_hole_math.calc_k_squared(p: float, bh_mass: float)

   Calculate the squared modulus of elliptic integral

   .. math::

      k^2 = m = \frac{Q - P + 6M}{2Q}

   .. attention::

      :cite:t:`Luminet_1979` uses the non-squared modulus in the elliptic integrals.
      This is just a convention. However, ``scipy`` asks for the squared modulus :math:`m=k^2`, not the modulus.

   :Parameters: * **p** (*float*) -- periastron distance
                * **bh_mass** (*float*) -- Black hole mass