code: def _find_indices(self, x):
          
          # find relevant edges between which xi are situated
          index_vecs = []
          # compute distance to lower edge in unity units
          norm_distances = []
  
          # iterate through dimensions
          for xi, cvec in zip(x, self.coord_vecs):
              idcs = np.searchsorted(cvec, xi) - 1
  
              idcs[idcs < 0] = 0
              idcs[idcs > cvec.size - 2] = cvec.size - 2
              index_vecs.append(idcs)
  
              norm_distances.append((xi - cvec[idcs]) /
                                    (cvec[idcs + 1] - cvec[idcs]))
  
          return index_vecs, norm_distances
docs: Find indices and distances of the given nodes.
  
          Can be overridden by subclasses to improve efficiency.