63)
              </p>
            </td>
</tr>
<tr>
<td>
              <p>
                number&lt;mpfr_float_backend&lt;50&gt;, et_off&gt;<br> (but with
                rvalue reference support)
              </p>
            </td>
<td>
              <p>
                1.1 (6.29s)
              </p>
            </td>
<td>
              <p>
                2.64 (4260868)
              </p>
            </td>
</tr>
<tr>
<td>
              <p>
                <a href="http://math.berkeley.edu/~wilken/code/g