Revision bfc623dd645245240f395e6fa3af15d260d380c5 authored by Douglas Bates on 15 August 2006, 00:00:00 UTC, committed by Gabor Csardi on 15 August 2006, 00:00:00 UTC
1 parent 40bc650
LU-class.Rd
\name{LU-class}
\docType{class}
\alias{LU-class}
\alias{expand,LU-method}
\title{LU Matrix Decompositions}
\description{
The \code{"LU"} class is the class of LU decompositions of
real matrices.
}
\section{Objects from the Class}{
Objects can be created by calls of the form \code{new("LU", ...)}.
More commonly the objects are created explicitly from calls of the form
\code{lu(mm)} where \code{mm} is an object that inherits from the
\code{"dgeMatrix"} class or as a side-effect of other functions applied
to \code{"dgeMatrix"} objects.
}
\section{Slots}{
\describe{
\item{\code{x}:}{object of class \code{"numeric"}. The \code{"L"}
(unit lower triangular) and \code{"U"} (upper triangular) factors
of the original matrix. These are stored in a packed format
described in the Lapack manual.}
\item{\code{Dim}:}{Object of class \code{"integer"} - the dimensions
of the original matrix - must be an integer vector with exactly two
non-negative values.}
\item{\code{pivot}:}{Object of class \code{"integer"} - a vector of
length \code{min(Dim)} that describes the permutation applied to
the rows of the original matrix. The contents of this vector are
described in the Lapack manual.}
}
}
\section{Methods}{
\describe{
\item{expand}{\code{signature(x = "LU")}: Produce the \code{"L"} and
\code{"U"} factors as a named list of matrices.}
}
}
% \references{}
% \author{}
% \note{}
\seealso{
class \code{\linkS4class{dgeMatrix}} and functions \code{\link{lu}},
\code{\link{expand}}.
}
\examples{
mm <- Matrix(round(rnorm(9),2), nrow = 3, ncol = 3)
mm
str(lum <- lu(mm))
elu <- expand(lum)
elu
elu$L \%*\% elu$U
}
\keyword{classes}
\keyword{algebra}
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