

\subsection{\bf 4.4\hspace{1em} The Real World and $\chi^2$}
\subsection{\bf Minimization---I}

\begin{slide}
\begin{itemize}
\item For a real problem, the iterative method described in Section
4.3 always diverges: one must invent various artistic devices to
ensure procedure converges.

\item The simplest reliable algorithm is called {\em Marquardt's\/}
method and this is intuitively easy to understand.

\item Consider $\chi^2$ as a function of several parameters.

\vspace*{10pt}
\centerline{\psfig{figure=fig14.phys.ps,clip=true,width=2.75in}}
\vspace*{10pt}
\end{itemize}
\end{slide}

