

    \filetitle{xsf}{Power spectrum and spectral density functions for VAR variables}{VAR/xsf}

	\paragraph{Syntax}
 
 \begin{verbatim}
 [S,D] = xsf(V,FREQ,...)
 \end{verbatim}
 \paragraph{Input arguments}
 
 \begin{itemize}
 \item
   \texttt{V} {[} VAR {]} - VAR object.
 \item
   \texttt{FREQ} {[} numeric {]} - Vector of Frequencies at which the
   XSFs will be evaluated.
 \end{itemize}
 \paragraph{Output arguments}
 
 \begin{itemize}
 \item
   \texttt{S} {[} numeric {]} - Power spectrum matrices.
 \item
   \texttt{D} {[} numeric {]} - Spectral density matrices.
 \end{itemize}
 \paragraph{Options}
 
 \begin{itemize}
 \item
   \texttt{'applyTo='} {[} cellstr \textbar{} char \textbar{}
   \emph{\texttt{':'}} {]} - List of variables to which the
   \texttt{'filter='} will be applied; \texttt{':'} means all variables.
 \item
   \texttt{'filter='} {[} char \textbar{} \emph{empty} {]} - Linear
   filter that is applied to variables specified by `applyto'.
 \item
   \texttt{'nFreq='} {[} numeric \textbar{} \emph{256} {]} - Number of
   equally spaced frequencies over which the `filter' is numerically
   integrated.
 \item
   \texttt{'progress='} {[} \texttt{true} \textbar{}
   \emph{\texttt{false}} {]} - Display progress bar in the command
   window.
 \end{itemize}
 \paragraph{Description}
 
 The output matrices, \texttt{S} and \texttt{D}, are
 \texttt{N}-by-\texttt{N}-by-\texttt{K}, where \texttt{N} is the number
 of VAR variables and \texttt{K} is the number of frequencies (i.e.~the
 length of the vector \texttt{freq}).
 
 The k-th page is the \texttt{S} matrix, i.e. \texttt{S(:,:,k)}, is the
 cross-spectrum matrix for the VAR variables at the k-th frequency.
 Similarly, the \texttt{k}-th page in \texttt{D}, i.e. \texttt{D(:,:,k)},
 is the cross-density matrix.
 
 \paragraph{Example}


