\section{ISINF Test for infinities}

\subsection{Usage}

Returns true for entries of an array that are infs (i.e.,
infinities).  The usage is
\begin{verbatim}
   y = isinf(x)
\end{verbatim}
The result is a logical array of the same size as \verb|x|,
which is true if \verb|x| is not-a-number, and false otherwise.
Note that for \verb|complex| or \verb|dcomplex| data types that
the result is true if either the real or imaginary parts
are infinite.
\subsection{Example}

Suppose we have an array of floats with one element that
is \verb|inf|:
\begin{verbatim}
--> a = [1.2 3.4 inf 5]

a = 

    1.2000    3.4000       inf    5.0000 

--> isinf(a)

ans = 

 0 0 1 0 

--> b = 3./[2 5 0 3 1]

b = 

    1.5000    0.6000       inf    1.0000    3.0000 


\end{verbatim}
