&nbsp; but often gives poor quality. <br>
      <i>h-ipm - </i>hybrid ipm that&nbsp; uses partial c-ipm followed
by ipm on each level <br>
      <i><br>
      </i></td>
    </tr>
    <tr>
      <td>&nbsp;&nbsp;&nbsp; <span style="font-style: italic;">PHG_COARSENING_LIMIT</span><br>
      </td>
      <td>Number of vertices at which to stop coarsening.<br>
      </td>
    </tr>
    <tr>
      <td style="vertical-align: top;">&nbsp;&nbsp;&nbsp; <span
 style="font-style: italic;">PHG_VERTEX_VISIT_ORDER</span><b