\section{SPONES Sparse Ones Function}

\subsection{Usage}

Returns a sparse \verb|float| matrix with ones where the argument
matrix has nonzero values.  The general syntax for it is
\begin{verbatim}
  y = spones(x)
\end{verbatim}
where \verb|x| is a matrix (it may be full or sparse).  The output
matrix \verb|y| is the same size as \verb|x|, has type \verb|float|, and contains
ones in the nonzero positions of \verb|x|.
\subsection{Examples}

Here are some examples of the \verb|spones| function
\begin{verbatim}
--> a = [1,0,3,0,5;0,0,2,3,0;1,0,0,0,1]

a = 

 1 0 3 0 5 
 0 0 2 3 0 
 1 0 0 0 1 

--> b = spones(a)

b = 
	Matrix is sparse with 7 nonzeros
--> full(b)

ans = 

 1 0 1 0 1 
 0 0 1 1 0 
 1 0 0 0 1 


\end{verbatim}
