# Pairwise

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##### Generic Pairwise Interaction model

Creates an instance of a pairwise interaction point process model which can then be fitted to point pattern data.

Keywords
spatial
##### Usage
Pairwise(pot, name)
Pairwise(pot, name, par, parnames)
##### Arguments
pot
An S language function giving the user-supplied pairwise interaction potential.
name
Character string.
par
List of numerical values for irregular parameters
parnames
Vector of names of irregular parameters
##### Details

Advanced use only. This code constructs a member of the pairwise interaction family pairwise.family with arbitrary pairwise interaction potential given by the user.

The function pot must take as its first argument a matrix of interpoint distances, and evaluate the potential for each of these distances. The result must be either a matrix with the same dimensions as its input, or an array with its first two dimensions the same as its input (the latter case corresponds to a vector-valued potential).

If irregular parameters are present, then the second argument to pot should be a vector of the same type as par giving those parameter values.

##### Value

• An object of class "interact" describing the interpoint interaction structure of a point process.

##### synopsis

Pairwise(pot, name, par, parnames, printfun)

ppm, pairwise.family, ppm.object

• Pairwise
##### Examples
#This is the same as StraussHard(r=0.7,h=0.2)
strpot <- function(t,par) {
r <- par$r h <- par$h
value <- (t <= r)
value[t < h] <- -Inf
value
}
mySH <- Pairwise(strpot, "StraussHard", list(r=0.7,h=0.2),
c("interaction distance r", "hard core distance c"))
data(cells)
ppm(cells, ~ 1, mySH)
Documentation reproduced from package spatstat, version 1.6-9, License: GPL version 2 or newer

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