\section{isempty --- Test for zero length matrix}
\label{fn:isempty}
\index{isempty()}
\index{test for zero length matrix}
\begin{rail}
Isempty : 'isempty' '(' Matrix  ')' ;
\end{rail}

\verb+isempty+ returns $1$ if the argument matrix is not empty. 
Otherwise it returns $0$.

$\Longrightarrow$ This is not an \RLaB\ built-in function.  This function
is normally loaded on start-up from the \verb+isempty.r+ file in the
standard \verb+rlib+ directory. Use of the \verb+-r+ option, incorrectly 
setting the \verb+RLAB_LIB_DIR+ environmental variable, or modifying
\verb+isempty.r+ may make this function unavailable.


\paragraph{Example}
\index{example of isempty()}
\index{isempty()!example}
\begin{verbatim}
> isempty([2,4])
        0  
> isempty([])
        1  
> isempty(zeros(1,1))
        0  
> isempty(zeros(0,0))
        1  
> isempty(eye(0,0))
        1  
> a = []
 a =
        []
> isempty(a)
        1  
\end{verbatim}


\newpage



