docs: def set_centralized_assembled_rows_cols(self, irn, jcn):
          """Set assembled matrix indices on processor 0.
  
          The row and column indices (irn & jcn) should be one based.
          """
          if self.myid != 0:
              return
          assert irn.size == jcn.size
          self._refs.update(irn=irn, jcn=jcn)
          self.id.nz = irn.size
          self.id.irn = self.cast_array(irn)
          self.id.jcn = self.cast_array(jcn)