\section{ISVECTOR Test For a Vector}

\subsection{Usage}

This function tests to see if the argument is a vector.  The 
syntax for \verb|isvector| is
\begin{verbatim}
   x = isvector(y)
\end{verbatim}
and it returns a logical 1 if the argument is size \verb|N x 1| or
\verb|1 x N| and a logical 0 otherwise.
