code: def localize(self, inod):
          
          remap = nm.empty((self.n_nod,), dtype=nm.int32)
          remap.fill(-1)
          remap[inod] = nm.arange(inod.shape[0], dtype=nm.int32)
  
          self.coors = self.coors[inod]
          self.ngroups = self.ngroups[inod]
          conns = []
          mat_ids = []
          for ig, conn in enumerate(self.conns):
              if conn.shape[0] == 0:
                  continue
  
              aux = remap[conn]
              ii = nm.unique(nm.where(aux == -1)[0])
              ii = nm.setdiff1d(nm.arange(conn.shape[0], dtype=nm.int32), ii)
              conns.append(aux[ii])
              mat_ids.append(self.mat_ids[ig][ii])
          self.conns = conns
          self.mat_ids = mat_ids
  
          self._set_shape_info()
docs: Strips nodes not in inod and remaps connectivities.
          Omits elements where remap[conn] contains -1...