dtRMatrix-class {Matrix} | R Documentation |

## Triangular Sparse Compressed Row Matrices

### Description

The `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.

### Objects from the Class

This class is currently still mostly unimplemented!

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

.

### Slots

`uplo`

:Object of class `"character"`

. Must be
either "U", for upper triangular, and "L", for lower triangular.
At present only the lower triangle form is allowed.

`diag`

:Object of class `"character"`

. Must be
either `"U"`

, for unit triangular (diagonal is all ones), or
`"N"`

; see `triangularMatrix`

.

`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. (Only present in the `dsRMatrix`

class.)

`x`

:Object of class `"numeric"`

- the non-zero
elements of the matrix.

`Dim`

:The dimension (a length-2 `"integer"`

)

`Dimnames`

:corresponding names (or `NULL`

),
inherited from the `Matrix`

, see there.

### Extends

Class `"dgRMatrix"`

, directly.
Class `"dsparseMatrix"`

, by class `"dgRMatrix"`

.
Class `"dMatrix"`

, by class `"dgRMatrix"`

.
Class `"sparseMatrix"`

, by class `"dgRMatrix"`

.
Class `"Matrix"`

, by class `"dgRMatrix"`

.

### Methods

No methods currently with class "dsRMatrix" in the signature.

### See Also

Classes `dgCMatrix`

, `dgTMatrix`

,
`dgeMatrix`

### Examples

```
(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
```

[Package

*Matrix* version 1.5-3

Index]