\HeaderA{dtRMatrix-class}{Triangular Sparse Compressed Row Matrices}{dtRMatrix.Rdash.class}
\keyword{classes}{dtRMatrix-class}
\keyword{algebra}{dtRMatrix-class}
\begin{Description}\relax
The \code{dtRMatrix} class is a class of triangular, sparse
matrices in the compressed, row-oriented format.  In this
implementation the non-zero elements in the rows are sorted into
increasing columnd order.
\end{Description}
\begin{Section}{Objects from the Class}
This class is currently still mostly unimplemented!

Objects can be created by calls of the form \code{new("dtRMatrix", ...)}.
\end{Section}
\begin{Section}{Slots}
\describe{
\item[\code{uplo}:] Object of class \code{"character"}. Must be
either "U", for upper triangular, and "L", for lower triangular.
At present only the lower triangle form is allowed.
\item[\code{diag}:] Object of class \code{"character"}. Must be
either \code{"U"}, for unit triangular (diagonal is all ones), or
\code{"N"}; see \code{\LinkA{triangularMatrix}{triangularMatrix.Rdash.class}}.
\item[\code{j}:] Object of class \code{"integer"} of length
\code{\LinkA{nnzero}{nnzero}(.)} (number of non-zero elements).  These are
the row numbers for each non-zero element in the matrix.
\item[\code{p}:] Object of class \code{"integer"} of pointers, one
for each row, to the initial (zero-based) index of elements in
the row. (Only present in the \code{dsRMatrix} class.)
\item[\code{x}:] Object of class \code{"numeric"} - the non-zero
elements of the matrix.
\item[\code{Dim}:] The dimension (a length-2 \code{"integer"})
\item[\code{Dimnames}:] corresponding names (or \code{NULL}),
inherited from the \code{\LinkA{Matrix}{Matrix.Rdash.class}}, see there.
}
\end{Section}
\begin{Section}{Extends}
Class \code{"dgRMatrix"}, directly.
Class \code{"dsparseMatrix"}, by class \code{"dgRMatrix"}.
Class \code{"dMatrix"}, by class \code{"dgRMatrix"}.
Class \code{"sparseMatrix"}, by class \code{"dgRMatrix"}.
Class \code{"Matrix"}, by class \code{"dgRMatrix"}.
\end{Section}
\begin{Section}{Methods}
No methods currently with class "dsRMatrix" in the signature.
\end{Section}
\begin{SeeAlso}\relax
Classes \code{\LinkA{dgCMatrix}{dgCMatrix.Rdash.class}}, \code{\LinkA{dgTMatrix}{dgTMatrix.Rdash.class}},
\code{\LinkA{dgeMatrix}{dgeMatrix.Rdash.class}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
(m0 <- new("dtRMatrix"))
(m2 <- new("dtRMatrix", Dim = c(2L,2L),
                        x = c(5, 1:2), p = c(0L,2:3), j= c(0:1,1L)))
str(m2)
(m3 <- as(Diagonal(2), "RsparseMatrix"))# --> dtRMatrix
\end{ExampleCode}
\end{Examples}

