
\subsection{\bf Analysis of Parallel Red Black Gauss Seidel}

\begin{slide}

\begin{itemize}
\item This can be parallelized as easily as Jacobi!  

\hspace{5pt} $\bullet$ Phase I follows by Phase II.

\item Red black is a different ordering from original Gauss Seidel.

\item For (some) elliptic problems, can show red black as good as and
maybe better than original ordering.

\begin{description}
\item[---] i.e., red black does not need more iterations than pure
Gauss Seidel.
\end{description}

\item For related hyperbolic problems---see NAS benchmark SSOR
discussion in CPS713---not so clear.

\item For higher order differencing, need more phases (more colors)
but principle the same.

\item Also not clear how to use if irregular matrix, as in sparse
matrices from power systems.
\end{itemize}

\end{slide}

