\HeaderA{qr-methods}{QR Decomposition -- S4 Methods and Generic}{qr.Rdash.methods}
\aliasA{qr}{qr-methods}{qr}
\aliasA{qr,dgCMatrix-method}{qr-methods}{qr,dgCMatrix.Rdash.method}
\aliasA{qr,sparseMatrix-method}{qr-methods}{qr,sparseMatrix.Rdash.method}
\keyword{methods}{qr-methods}
\keyword{algebra}{qr-methods}
\keyword{array}{qr-methods}
\begin{Description}\relax
The \code{"Matrix"} package provides methods for the QR decomposition
of special classes of matrices.  There is a generic function which uses
\code{\LinkA{qr}{qr}} as default, but methods defined in this package
can take extra arguments.  In particular there is an option for
determining a fill-reducing permutation of the columns of a sparse,
rectangular matrix.
\end{Description}
\begin{Section}{Methods}
\describe{
\item[x = "dgCMatrix"] QR decomposition of a general sparse
double-precision matrix with \code{nrow(x) >= ncol(x)}.  Returns
an object of class \code{"sparseQR"}, see
\code{\LinkA{sparseQR}{sparseQR.Rdash.class}}.
\item[x = "sparseMatrix"] works via \code{"dgCMatrix"}.
}
\end{Section}
\begin{SeeAlso}\relax
\code{\LinkA{qr}{qr}}, \code{\LinkA{sparseQR}{sparseQR.Rdash.class}},
\code{\LinkA{dgCMatrix}{dgCMatrix.Rdash.class}}
\end{SeeAlso}

