assemble_z_jets
===============

.. py:function:: t3toolbox.backend.sampling_derivatives.assemble_z_jets(tucker_cores, eta_jets)

   .. code-block:: python

      def assemble_z_jets(
              tucker_cores:   typ.Sequence[NDArray],  # len=d, elm_shape=C+(nUi,Ni)
              eta_jets:       typ.Sequence[NDArray],  # len=d, elm_shape=(order+1,)+W+C+(nUi,)
      ) -> typ.Tuple[NDArray, ...]:                   # z_jets. len=d, elm_shape=(order+1,)+W+C+(Ni,)


   Lift the combined jets back to the ambient modes through the Tucker cores (order by order).

   The Tucker factor is order-independent, so ``z_i^(t) = U_i eta_i^(t)`` applies per order
   (``tWCi_Cio_to_tWCo``) -- the order axis rides as a leading broadcast batch.