

    \filetitle{diff}{First difference}{tseries/diff}

	\paragraph{Syntax}
 
 \begin{verbatim}
 Y = diff(X)
 Y = diff(X,K)
 \end{verbatim}
 \paragraph{Input arguments}
 
 \begin{itemize}
 \item
   \texttt{X} {[} tseries {]} - Input tseries object.
 \item
   \texttt{K} {[} numeric {]} - Number of periods over which the first
   difference will be computed; Y = X - X\{K\}. Note that \texttt{K} must
   be a negative number for the usual backward differencing. If not
   entered, the default \texttt{-1} will be used.
 \end{itemize}
 \paragraph{Output arguments}
 
 \begin{itemize}
 \item
   \texttt{Y} {[} tseries {]} - First difference of the input data.
 \end{itemize}
 \paragraph{Description}
 
 \paragraph{Example}


