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Returns the theoretical
# S3 method for ppm
Kmodel(model, …) # S3 method for ppm
pcfmodel(model, …)
A fitted Poisson or Gibbs point process model (object of
class "ppm") typically obtained from
the model-fitting algorithm ppm.
Ignored.
A function in the R language,
which takes one argument r.
This function computes an approximation to the
The functions Kmodel and pcfmodel are generic.
The functions documented here are the methods for the class
"ppm".
The approximation is only available for stationary pairwise-interaction models. It uses the second order Poisson-saddlepoint approximation (Baddeley and Nair, 2012b) which is a combination of the Poisson-Boltzmann-Emden and Percus-Yevick approximations.
The return value is a function in the R language,
which takes one argument r.
Evaluation of this function, on a numeric vector r,
yields values of the desired
Baddeley, A. and Nair, G. (2012a) Fast approximation of the intensity of Gibbs point processes. Electronic Journal of Statistics 6 1155--1169.
Baddeley, A. and Nair, G. (2012b) Approximating the moments of a spatial point process. Stat 1, 1, 18--30. doi: 10.1002/sta4.5
Kest or pcf
to estimate the
ppm to fit Gibbs models.
Kmodel for the generic functions.
Kmodel.kppm for the method for cluster/Cox processes.
# NOT RUN {
fit <- ppm(swedishpines, ~1, Strauss(8))
p <- pcfmodel(fit)
K <- Kmodel(fit)
p(6)
K(8)
curve(K(x), from=0, to=15)
# }
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