\HeaderA{expand}{Expand a Decomposition into Factors}{expand}
\keyword{algebra}{expand}
\begin{Description}\relax
Expands decompositions stored in compact form into factors.
\end{Description}
\begin{Usage}
\begin{verbatim}
expand(x, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] a matrix decomposition.
\item[\code{...}] further arguments passed to or from other methods.
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
This is a generic function with special methods for different types
of decompositions, see \code{\LinkA{showMethods}{showMethods}(expand)} to list them
all.
\end{Details}
\begin{Value}
The expanded decomposition, typically a list of matrix factors.
\end{Value}
\begin{Note}\relax
Factors for decompositions such as \code{lu} and \code{qr} can be
stored in a compact form.
The function \code{expand} allows all factors to be fully expanded.
\end{Note}
\begin{SeeAlso}\relax
The LU decomposition \code{\LinkA{lu}{lu}}, for which there \emph{is} an
\code{expand} method;
\code{\LinkA{facmul}{facmul}}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
(x <- Matrix(round(rnorm(9),2), 3, 3))
(ex <- expand(lux <- lu(x)))
\end{ExampleCode}
\end{Examples}

