T3Variations.stack_shape
========================

.. py:method:: t3toolbox.frame_variations_format.T3Variations.stack_shape()

   .. code-block:: python

      def stack_shape(self) -> typ.Tuple[int,...]:   # full leading stack K + C (split-agnostic on its own)


   The full leading stack ``K + C`` shared by every variation core.

   ``T3Variations`` is **split-agnostic**: the tangent-stack ``K`` vs frame-stack ``C`` split is
   fixed only when paired with a :py:class:`T3Frame` (``check_fv_pair`` requires ``C`` to be the
   trailing/inner part of this stack; :py:class:`~t3toolbox.manifold.T3Tangent` then exposes the
   two parts). See ``docs/batching_and_stacking.md``.