ufv_make_frame_masks
====================

.. py:function:: t3toolbox.backend.ufv_masking.ufv_make_frame_masks(up_ranks, down_ranks, left_ranks, right_ranks, nU, nD, rL, rR)

   .. code-block:: python

      def ufv_make_frame_masks(
              up_ranks:    NDArray,   # HOST int, (d,)   + stack_shape
              down_ranks:  NDArray,   # HOST int, (d,)   + stack_shape
              left_ranks:  NDArray,   # HOST int, (d+1,) + stack_shape
              right_ranks: NDArray,   # HOST int, (d+1,) + stack_shape
              nU: int,
              nD: int,
              rL: int,
              rR: int,
      ) -> typ.Tuple[
          NDArray,  # up_mask,    HOST bool, (d,)   + stack_shape + (nU,)
          NDArray,  # down_mask,  HOST bool, (d,)   + stack_shape + (nD,)
          NDArray,  # left_mask,  HOST bool, (d+1,) + stack_shape + (rL,)
          NDArray,  # right_mask, HOST bool, (d+1,) + stack_shape + (rR,)
      ]:


   Build the prefix RANK edge masks for a uniform frame. The physical ``shape`` is a separate
   int tuple (not a mask), so this returns only the four rank masks. HOST numpy (masks are static
   structure -- ``np``, not ``xnp``; see ``docs/contributor/uniform_pytree_composition.md``).