nMatrix-class {Matrix} | R Documentation |

## Class "nMatrix" of Non-zero Pattern Matrices

### Description

The `nMatrix`

class is the virtual “mother” class of all
**n**on-zero pattern (or simply *patter***n**)
matrices in the Matrix package.

### Slots

Common to *all* matrix object in the package:

`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; each component
containing NULL or a `character`

vector length
equal the corresponding `Dim`

element.

### Methods

There is a bunch of coercion methods (for `as(..)`

), e.g.,

- coerce
`signature(from = "matrix", to = "nMatrix")`

:
Note that these coercions (must) coerce `NA`

s to
non-zero, hence conceptually `TRUE`

.
This is particularly important when
`sparseMatrix`

objects are coerced to
`"nMatrix"`

and hence to `nsparseMatrix`

.

- coerce
`signature(from = "dMatrix", to = "nMatrix")`

, and

- coerce
`signature(from = "lMatrix", to = "nMatrix")`

:
For dense matrices with `NA`

s, these
coercions are valid since Matrix version 1.2.0 (still with
a `warning`

or a `message`

if
`"Matrix.warn"`

, or `"Matrix.verbose"`

`options`

are set.)

- coerce
`signature(from = "nMatrix", to = "matrix")`

: ...

- coerce
`signature(from = "nMatrix", to = "dMatrix")`

: ...

- coerce
`signature(from = "nMatrix", to = "lMatrix")`

: ...

— — —

Additional methods contain group methods, such as

- Ops
`signature(e1 = "nMatrix", e2 = "....")`

, ...

- Arith
`signature(e1 = "nMatrix", e2 = "....")`

, ...

- Compare
`signature(e1 = "nMatrix", e2 = "....")`

, ...

- Logic
`signature(e1 = "nMatrix", e2 = "....")`

, ...

- Summary
`signature(x = "nMatrix", "....")`

, ...

### See Also

The classes `lMatrix`

,
`nsparseMatrix`

, and the mother class,
`Matrix`

.

### Examples

```
getClass("nMatrix")
L3 <- Matrix(upper.tri(diag(3)))
L3 # an "ltCMatrix"
as(L3, "nMatrix") # -> ntC*
## similar, not using Matrix()
as(upper.tri(diag(3)), "nMatrix")# currently "ngTMatrix"
```

[Package

*Matrix* version 1.5-1

Index]