dsRMatrix-class {Matrix} R Documentation

## Symmetric Sparse Compressed Row Matrices

### Description

The dsRMatrix class is a class of symmetric, sparse matrices in the compressed, row-oriented format. In this implementation the non-zero elements in the rows are sorted into increasing column order.

### Objects from the Class

These "..RMatrix" classes are currently still mostly unimplemented!

Objects can be created by calls of the form new("dsRMatrix", ...).

### Slots

uplo:

A character object indicating if the upper triangle ("U") or the lower triangle ("L") is stored. At present only the lower triangle form is allowed.

j:

Object of class "integer" of length nnzero (number of non-zero elements). These are the row numbers for each non-zero element in the matrix.

p:

Object of class "integer" of pointers, one for each row, to the initial (zero-based) index of elements in the row.

factors:

Object of class "list" - a list of factorizations of the matrix.

x:

Object of class "numeric" - the non-zero elements of the matrix.

Dim:

Object of class "integer" - the dimensions of the matrix - must be an integer vector with exactly two non-negative values.

Dimnames:

List of length two, see Matrix.

### Extends

Classes RsparseMatrix, dsparseMatrix and symmetricMatrix, directly.

Class "dMatrix", by class "dsparseMatrix", class "sparseMatrix", by class "dsparseMatrix" or "RsparseMatrix"; class "compMatrix" by class "symmetricMatrix" and of course, class "Matrix".

### Methods

forceSymmetric

signature(x = "dsRMatrix", uplo = "missing"): a trivial method just returning x

forceSymmetric

signature(x = "dsRMatrix", uplo = "character"): if uplo == x@uplo, this trivially returns x; otherwise t(x).

coerce

signature(from = "dsCMatrix", to = "dsRMatrix")

the classes dgCMatrix, dgTMatrix, and dgeMatrix.

### Examples

(m0 <- new("dsRMatrix"))
m2 <- new("dsRMatrix", Dim = c(2L,2L),
x = c(3,1), j = c(1L,1L), p = 0:2)
m2
stopifnot(colSums(as(m2, "TsparseMatrix")) == 3:4)
str(m2)
(ds2 <- forceSymmetric(diag(2))) # dsy*
dR <- as(ds2, "RsparseMatrix")
dR # dsRMatrix


[Package Matrix version 1.4-1 Index]