R: Triangular, dense, numeric matrices

dtrMatrix-class {Matrix} | R Documentation

## Triangular, dense, numeric matrices

### Description

The `"dtrMatrix"` class is the class of triangular, dense, numeric matrices in nonpacked storage. The `"dtpMatrix"` class is the same except in packed storage.

### Objects from the Class

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.

`diag`:

  Object of class `"character"`. Must be either `"U"`, for unit triangular (diagonal is all ones), or `"N"`; see `triangularMatrix`.

`x`:

  Object of class `"numeric"`. The numeric values that constitute the matrix, stored in column-major order.

`Dim`:

  Object of class `"integer"`. The dimensions of the matrix which must be a two-element vector of non-negative integers.

### Extends

Class `"ddenseMatrix"`, directly. Class `"triangularMatrix"`, directly. Class `"Matrix"` and others, by class `"ddenseMatrix"`.

### Methods

Among others (such as matrix products, e.g. `?crossprod-methods`),

coerce

  `signature(from = "dgeMatrix", to = "dtrMatrix")`

coerce

  `signature(from = "dtrMatrix", to = "matrix")`

coerce

  `signature(from = "dtrMatrix", to = "ltrMatrix")`

coerce

  `signature(from = "dtrMatrix", to = "matrix")`

coerce

  `signature(from = "matrix", to = "dtrMatrix")`

norm

  `signature(x = "dtrMatrix", type = "character")`

rcond

  `signature(x = "dtrMatrix", norm = "character")`

solve

  `signature(a = "dtrMatrix", b = "....")`

efficientely use a “forwardsolve” or `backsolve` for a lower or upper triangular matrix, respectively, see also `solve-methods`.

+, -, *, ..., ==, >=, ...

  all the `Ops` group methods are available. When applied to two triangular matrices, these return a triangular matrix when easily possible.

### See Also

Classes `ddenseMatrix`, `dtpMatrix`, `triangularMatrix`

### Examples

    (m <- rbind(2:3, 0:-1))
    (M <- as(m, "dgeMatrix"))

    (T <- as(M, "dtrMatrix")) ## upper triangular is default
    (T2 <- as(t(M), "dtrMatrix"))
    stopifnot(T@uplo == "U", T2@uplo == "L", identical(T2, t(T)))

[Package Matrix version 1.3-4 Index]