\section{RCOND Reciprocal Condition Number Estimate}

\subsection{Usage}

The \verb|rcond| function is a FreeMat wrapper around LAPACKs
function \verb|XGECON|, which estimates the 1-norm condition
number (reciprocal).  For the details of the algorithm see
the LAPACK documentation.  The syntax for its use is
\begin{verbatim}
   x = rcond(A)
\end{verbatim}
where \verb|A| is a matrix.
\subsection{Example}

Here is the reciprocal condition number for a random square
matrix
\begin{verbatim}
--> A = rand(30);
--> rcond(A)
ans = 
  <double>  - size: [1 1]
 6.631801037021418e-04  

\end{verbatim}
And here we calculate the same value using the definition of
(reciprocal) condition number
\begin{verbatim}
--> 1/(norm(A,1)*norm(inv(A),1))
ans = 
  <double>  - size: [1 1]
 6.505510742818196e-04  

\end{verbatim}
Note that the values are very similar.  LAPACKs \verb|rcond|
function is far more efficient than the explicit calculation
(which is also used by the \verb|cond| function.
