UniformGaussNewtonModel.gn_hessian
==================================

.. py:method:: t3toolbox.fitting.UniformGaussNewtonModel.gn_hessian(p)

   .. code-block:: python

      def gn_hessian(self, p: ut3m.UT3Tangent) -> ut3m.UT3Tangent:  # H p = Π 𝒥ᵀ 𝒥 Π p (+ H_R p)


   The Gauss-Newton Hessian action ``H p = Π 𝒥ᵀ 𝒥 Π p`` (``H = JᵀJ``), a UT3Tangent at frame, plus
   the regularizer term ``H_R p`` when set.