

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

	\paragraph{Syntax}

\begin{verbatim}
X = diff(X)
X = 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; \texttt{Y = X - X\{K\}}. Note that
  \texttt{K} must be a negative number for the usual backward
  differencing. If not specified, \texttt{K} will be set to \texttt{-1}.
\end{itemize}

\paragraph{Output arguments}

\begin{itemize}
\itemsep1pt\parskip0pt\parsep0pt
\item
  \texttt{X} {[} tseries {]} - First difference of the input data.
\end{itemize}

\paragraph{Description}

\paragraph{Example}


