tPoint(Int_t i, Double_t &amp;x, Double_t &amp;y) const
    </pre>
    The function returns -1 in case of an invalid request or the
    point number otherwise.
  </li>
<li>    Re-implement <tt>TGraph::Fit</tt> using the functions defined in <tt>HFitImpl.cxx</tt>.

</ul>

<h4>TGraph2D</h4>
<ul>
  <li>    Re-implement <tt>TGraph2D::Fit</tt> using the functions defined in <tt>HFitImpl.cxx</tt>.
        <li>Add possibility to be used in the FitPanel (add a <tt>TGraph2D::FitPanel()</tt> method).
</ul>

<h4>TMult