

\subsection{\bf Shift Register Pseudorandom}
\subsection{\bf Numbers---Overview}

\begin{slide}
\begin{itemize}
\item The shift register methods are not discussed (correctly) in
Knuth, and may well be better, as they are as easy to calculate and
have longer period.

\item Chiu has implemented a particularly simple method.
\[
I_j = I_{j-q} \oplus I_{j-p}
\]
where $\oplus = $ Exclusive OR
\begin{eqnarray*}
1\oplus 1 & = & 0 \\
1\oplus 0 & = & 0\oplus 1 = 1 \\
0\oplus 0 & = & 0
\end{eqnarray*}
This $\oplus$ operates independently on each bit of the numbers
$I_{j-q}$, $I_{j-p}$.

\item The period of this could be as large as $2^p-1$, which is big
for Chiu's choice $p=250$, $q=147$.
\end{itemize}
\end{slide}

