d>
          </tr>
          <tr>
            <td style="font-family: Courier New,Courier,monospace;">bool
            <span style="font-weight: bold;">is_primary</span>() const </td>
            <td>Returns false if the edge
goes through the endpoint of the segment site, else true. </td>
          </tr>
          <tr>
            <td style="font-family: Courier New,Courier,monospace;">bool
            <span style="font-weight: bold;">is_secondary</span>() const</td>
            <td>Returns true if the edge