utv_probe
=========

.. py:function:: t3toolbox.backend.utv_sampling.utv_probe(ww, frame_data, variations_data)

   .. code-block:: python

      def utv_probe(
              ww,               # probe vectors, len=d, ith elm_shape=W+(Ni,)
              frame_data,       # UT3Frame .data
              variations_data,  # UT3Variations .data
      ):  # -> MIRRORS ww: ragged -> len=d tuple (W+K+C+(Ni,)); packed -> (d,)+W+K+C+(N,)


   Probe a uniform tangent vector (the bare ``𝒥``): mask-once, share ``probing.tv_probe``.
   **Mirrors** ``ww``'s packedness (ragged -> the d probes sliced to real widths; packed -> the packed array).