An S4 class to represent a stratigraphic matrix.

A stratigraphic matrix represents directed relationships between stratigraphic units. A stratigraphic matrix is an adjacency matrix (a non symmetric square matrix with zeros on its main diagonal), suitable to build a directed acyclic graph (DAG).

In the code snippets below, `x`

is a `*Matrix`

object.

`length(x)`

Returns the length of

`x`

.`dim(x)`

Returns the dimension of

`x`

.`nrow(x)`

Returns the number of rows present in

`x`

.`ncol(x)`

Returns the number of columns present in

`x`

.`dimnames(x)`

,`dimnames(x) <- value`

Retrieves or sets the row dimnames of

`x`

according to`value`

.`rownames(x)`

,`rownames(x) <- value`

Retrieves or sets the row names of

`x`

according to`value`

.`colnames(x)`

,`colnames(x) <- value`

Retrieves or sets the column names of

`x`

according to`value`

.

In the code snippets below, `x`

is a `*Matrix`

object.

`x[i, j, ..., drop]`

Extracts elements selected by subscripts

`i`

and`j`

. Indices are`numeric`

or`character`

vectors or empty (missing) or`NULL`

. Numeric values are coerced to`integer`

as by`as.integer`

(and hence truncated towards zero). Character vectors will be matched to the`dimnames`

of the object. An empty index (a comma separated blank) indicates that all entries in that dimension are selected. Returns an object of the same class as`x`

.`x[[i]]`

Extracts a single element selected by subscript

`i`

.

Other matrix:
`AbundanceMatrix-class`

,
`CountMatrix-class`

,
`DataMatrix-class`

,
`GenericMatrix-class`

,
`IncidenceMatrix-class`

,
`OccurrenceMatrix-class`

,
`SimilarityMatrix-class`

,
`coerce()`

N. Frerebeau

# Principles of Archaeological Stratigraphy, fig. 12 harris <- matrix( data = c(2, 1, 3, 1, 4, 1, 5, 2, 5, 3, 5, 4, 6, 5, 7, 1, 7, 6, 8, 1, 8, 6, 9, 7, 9, 8), ncol = 2, byrow = TRUE, dimnames = list(NULL, c("lower", "upper")) ) strati <- as_stratigraphy(harris)