
\subsection{\bf Estimate of Over Relaxation Parameter $\omega$}

\begin{slide}

\begin{itemize}
\item Thus, in general for practical problems, one cannot precalculate
optimal overrelaxation parameter.  

\item Find $\omega$ by numerical experimentation.

\item However, note that one can expect a choice $1< \omega < 2$ to be
better than natural $\omega = 1$.
\end{itemize}
 
\begin{itemize}
\item One can use the estimate

\begin{eqnarray*}
\omega_{opt} & = & 2 - \frac{\mbox{constant}}{N} \\
& = & 2 - \mbox{constant}\ \cdot\ h \\
\end{eqnarray*}

($h$ is grid spacing)
\end{itemize}


\end{slide}

