``c_reduced_lat_from_geodetic_lat``
===================================

.. c:function:: double Ellipsoid.c_reduced_lat_from_geodetic_lat(double geodetic_lat)

Compute the reduced (parametric) latitude :math:`\beta` from a geodetic latitude :math:`\phi`.

.. math::
    \beta = \arctan\bigl((1 - f)\,\tan\phi\bigr)


All angles are in radians (SI).

:param geodetic_lat: 
    Geodetic latitude :math:`\phi` in radians on the reference ellipsoid.

:returns: 
    Reduced (parametric) latitude :math:`\beta` in radians.

:rtype: 
    float


.. seealso::
    :c:func:`c_geodetic_lat_from_reduced_lat <Ellipsoid.c_geodetic_lat_from_reduced_lat>`
        Inverse transform (φ from β).
    :meth:`reduced_lat_from_geodetic_lat <Ellipsoid.reduced_lat_from_geodetic_lat>`
        Vectorized Python wrapper.

.. note::
    Releases the GIL and uses a low-level C implementation for speed.