R: Relation Equivalence Classes

classes {relations} | R Documentation

## Relation Equivalence Classes

### Description

Provide class ids or classes, respectively, for an equivalence relation or the indifference relation of a weak order.

### Usage

    relation_class_ids(x)
    relation_classes(x)

### Arguments

`x` | an object inheriting from class `relation` representing a crisp endorelation.

### Value

For `relation_class_ids()`, a numeric vector with class ids corresponding to the classes of the equivalence relation, or the indifference relation of the weak order with ids ordered according to increasing preference.

For `relation_classes()`, an object of class `relation_classes_of_objects`, which is a list of sets giving the elements in the corresponding classes, named by the class ids.

### Examples

    ## Equivalence.
    f <- factor(rep(c("Good", "Bad", "Ugly"), c(3, 2, 1)))
    R <- as.relation(f)
    relation_is(R, "equivalence")
    table(ids = relation_class_ids(R), orig = f)

    relation_classes(R)

    ## Weak order ("weak preference").
    f <- ordered(f, levels = c("Ugly", "Bad", "Good"))
    R <- as.relation(f)
    relation_is(R, "weak_order")
    table(ids = relation_class_ids(R), orig = f)

    relation_classes(R)

[Package relations version 0.6-7 Index]