code: def _compute_Lp_matrix(self):
          
          self.Lp = sum([1/self.eigen_values[i]
                        * np.outer(self.eigen_basis[:, i], self.eigen_basis[:, i])
                        for i in range(1, self.eigen_values.size)])
docs: See Fouss et al. (2006) and von Luxburg et al. (2007).
  
          See Proposition 6 in von Luxburg (2007) and the inline equations
          right in the text above.