spatstat (version 1.31-3)

as.function.fv: Convert Function Value Table to Function

Description

Converts an object of class "fv" to an Rlanguage function.

Usage

## S3 method for class 'fv':
as.function(x, ..., value, extrapolate=FALSE)
  ## S3 method for class 'rhohat':
as.function(x, ..., value, extrapolate=TRUE)

Arguments

x

Object of class "fv"

...

Ignored.

value

Optional. String selecting one of the columns of x for use as the function value.

extrapolate

Logical value indicating whether to extrapolate the function outside the domain of x. See Details.

Value

• A function with one argument.

Details

A function value table (object of class "fv") is a convenient way of storing and plotting several different estimates of the same function. Objects of this class are returned by many commands in spatstat, such as Kest which returns an estimate of Ripley's $K$-function for a point pattern dataset.

Sometimes it is useful to convert the function value table to a function in the Rlanguage. This is done by as.function.fv. It converts an object x of class "fv" to an Rfunction f.

If f <- as.function(x) then f is a function with one numeric argument, that performs linear interpolation between the values in the table x.

Argument values lying outside the range of the table yield an NA value (if extrapolate=FALSE) or the function value at the nearest endpoint of the range (if extrapolate = TRUE).

The command as.function.fv is a method for the generic command as.function.

See Also

fv, fv.object, plot.fv, Kest

Examples

data(cells)
  K <- Kest(cells)
  f <- as.function(K)
  f(0.1)