Range of Distribution

Range returns a vector of length two, with the minimum and maximum values of the (support of the) distribution.

The support method gives the smallest and largest values the support reaches — its two outermost points, taking the atoms and the continuous regions together. Gaps in between are not represented.

An empty support reaches nothing, and its range is c(Inf, -Inf) — what R gives for the range of nothing, and reversed on purpose, being the identity for combining ranges.

Usage

# S3 method for class 'dst'
range(distribution, ...)

# S3 method for class 'support'
range(support, ...)

Arguments

distribution

Distribution to compute range from.

...

Not used; vestige of the base::range() S3 generic.

support

A support object.

Value

Vector of length two, containing the minimum and maximum values of a distribution.

Details

The range is read from the distribution's support (see support()), which is where a distribution says what values it reaches. In this it behaves like vtype(): derived, not declared.

It is still a property, and eval_property() reaches it like any other, so code walking a list of property names need not know which are stored and which are worked out. What it cannot be is stated: distribution() refuses a range entry, since a stated one would be consulted ahead of the derived value and could disagree with it.

The Null distribution is a different case: it has no support at all, so neither end is known, and its range is c(NA, NA) — still a vector of length two, rather than a single NA. An empty support says there is nothing to reach; the Null distribution says nothing at all.

Examples

a <- dst_gp(1, 0.5)
b <- dst_unif(0, 1)
c <- dst_norm(3, 4)
range(a)
#> [1]   0 Inf
range(b)
#> [1] 0 1
range(c)
#> [1] -Inf  Inf
range(continuous(c(0, 1), c(3, 4)))
#> [1] 0 4
range(mixed(discrete = -1, continuous = c(0, Inf)))
#> [1]  -1 Inf
range(empty_support())
#> [1]  Inf -Inf