rder.m">tetrahedron_nco_suborder.m</a>
          returns the suborders for an NCO rule.
        </li>
        <li>
          <a href = "tetrahedron_nco_suborder_num.m">tetrahedron_nco_suborder_num.m</a>
          returns the number of suborders for an NCO rule.
        </li>
        <li>
          <a href = "tetrahedron_nco_subrule.m">tetrahedron_nco_subrule.m</a>
          returns a compressed NCO rule.
        </li>
        <li>
          <a href = "r8mat_det_4d.m">r8mat_det_4d.m</a>
          returns the