T3FrameWeights.from_t3weights
=============================

.. py:method:: t3toolbox.frame_variations_format.T3FrameWeights.from_t3weights(t3_weights)
   :classmethod:


   .. code-block:: python

      def from_t3weights(cls, t3_weights: 't3.T3Weights') -> 'T3FrameWeights':


   Build a tangent metric from base-point edge weights (e.g. ``T3Weights.from_t3svd(x)``):
   ``up = down = tucker_weights``, ``left = tt_weights[:-1]``, ``right = tt_weights[1:]``. The TT
   slicing follows the ``Hᵢ`` bond convention (``Hᵢ``'s left bond is TT bond ``i``, right bond
   ``i+1``) -- simple but convention-dependent, hence a named method. The result pairs with a
   **minimal-rank** tangent at ``x`` (where the complement rank ``nD`` equals the Tucker rank ``nU``,
   as for ``t3svd`` output); the Grasedyck–Kramer metric is
   ``T3FrameWeights.from_t3weights(T3Weights.from_t3svd(x)).reciprocal()``.