assemble_z
==========

.. py:function:: t3toolbox.backend.probing.assemble_z(tucker_cores, etas)

   .. code-block:: python

      def assemble_z(
              tucker_cores:   typ.Union[typ.Sequence[NDArray], NDArray],  # len=d. elm_shape=C+(ni,Ni)
              etas:           typ.Union[typ.Sequence[NDArray], NDArray],  # len=d. elm_shape=W+C+(ni,)
      ) -> typ.Union[typ.Sequence[NDArray], NDArray]: # zs. len=d, elm_shape=W+C+(Ni,)


   Assemble probes from downward edge variables.

   See Section 6.2, particularly Figure 7 and Algorithm 5, in:
       Alger, N., Christierson, B., Chen, P., & Ghattas, O. (2026).
       "Tucker Tensor Train Taylor Series."
       arXiv preprint arXiv:2603.21141.
       `https://arxiv.org/abs/2603.21141 <https://arxiv.org/abs/2603.21141>`_