spatstat (version 1.11-4)

quad.ppm: Extract Quadrature Scheme Used to Fit a Point Process Model

Description

Given a fitted point process model, this function extracts the quadrature scheme used to fit the model.

Usage

quad.ppm(object)

Arguments

object

fitted point process model (an object of class "ppm").

Value

• A quadrature scheme (object of class "quad").

Details

An object of class "ppm" represents a point process model that has been fitted to data. It is typically produced by the model-fitting algorithm ppm. The ppm algorithm approximates the pseudolikelihood integral by a sum over a finite set of quadrature points, which is constructed by augmenting the original data point pattern by a set of ``dummy'' points. The fitted model object returned by ppm contains complete information about this quadrature scheme. See ppm or ppm.object for further information. This function extracts the quadrature scheme. A typical use of this function would be to inspect the quadrature scheme (points and weights) to gauge the accuracy of the approximation to the exact pseudolikelihood.

See ppm.object for a list of all operations that can be performed on objects of class "ppm". See quad.object for a list of all operations that can be performed on objects of class "quad".

See Also

ppm.object, quad.object, ppm

Examples

data(cells)
 fit <- ppm(cells, ~1, Strauss(r=0.1), rbord=0.1)
 Q <- quad.ppm(fit)
 plot(Q)
 Q$data$n
 Q$dummy$n