

    \filetitle{movavg}{Moving average pseudofunction}{modellang/movavg}

	\paragraph{Syntax}
 
 \begin{verbatim}
 movavg(EXPR)
 movavg(EXPR,K)
 \end{verbatim}
 \paragraph{Description}
 
 If the second input argument, \texttt{K}, is negative, this function
 expands to the moving average of the last K periods (including the
 current period), i.e.
 
 \begin{verbatim}
 (((EXPR)+(EXPR{-1})+ ... +(EXPR{-(K-1)})/-K)
 \end{verbatim}
 where \texttt{EXPR\{-N\}} derives from \texttt{EXPR} and has all its
 time subscripts shifted by \texttt{-N} (if specified).
 
 If the second input argument, \texttt{K}, is positive, this function
 expands to the moving average of the next K periods ahead (including the
 current period), i.e.
 
 \begin{verbatim}
 (((EXPR)+(EXPR{1})+ ... +(EXPR{K-1})/K)
 \end{verbatim}
 If the second input argument, \texttt{K}, is not specified, the default
 value --4 is used (based on the fact that most of the macroeconomic
 models are quarterly).
 
 \paragraph{Example}
 
 The following three lines
 
 \begin{verbatim}
 movavg(Z)
 movavg(Z,-3)
 movavg(X+Y{-1},2)
 \end{verbatim}
 will expand to
 
 \begin{verbatim}
 (((Z)+(Z{-1})+(Z{-2})+(Z{-3}))/4)
 (((Z)+(Z{-1})+(Z{-2}))/3)
 (((X+Y{-1})+(X{1}+Y))/2)
 \end{verbatim}


