spatstat (version 1.13-0)

Pairwise: Generic Pairwise Interaction model

Description

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

Usage

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

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

printfun

Do not specify this argument: for internal use only.

Value

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

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.

See Also

ppm, pairwise.family, ppm.object

Examples

#This is the same as StraussHard(r=0.7,h=0.05)
   strpot <- function(d,par) {
         r <- par$r
         h <- par$h
         value <- (d <= r)
         value[d < h] <- -Inf
         value
   }
   mySH <- Pairwise(strpot, "StraussHard", list(r=0.7,h=0.05),
           c("interaction distance r", "hard core distance c"))
   data(cells)
   ppm(cells, ~ 1, mySH, correction="isotropic")