UT3Tangent.sum_tangents
=======================

.. py:method:: t3toolbox.uniform_manifold.UT3Tangent.sum_tangents(axis=None)

   .. code-block:: python

      def sum_tangents(self, axis=None) -> 'UT3Tangent':


   Sum over the tangent stack ``K`` (a batch of tangents at the shared frame) into one tangent.

   Corewise (= the tensor sum, by linearity); the frame stack ``C`` is preserved. ``axis`` indexes
   within ``K`` (default: the whole tangent stack). The masks OR over the summed axes -- a no-op for
   a single-frame ``K`` stack (constant masks), but the correct reduction in general.