RMcubic: Cubic Covariance Model
In RandomFields: Simulation and Analysis of Random Fields

Description Usage Arguments Details Value References See Also Examples

RMcubic is a stationary isotropic covariance model which is only valid for dimensions d ≤ 3 . The corresponding covariance function only depends on the distance r ≥ 0 between two points and is given by

C(r) = (1 -7 r^(2) + 8.75 r^3 - 3.5 r^5 + 0.75 r^7) 1_{[0,1]}(r).

1	RMcubic(var, scale, Aniso, proj)

var,scale,Aniso,proj

optional arguments; same meaning for any RMmodel. If not passed, the above covariance function remains unmodified.

The model is only valid for dimensions d ≤ 3 . It is a 2 times differentiable covariance function with compact support (cf. Chiles, J.-P. and Delfiner, P. (1999), p. 84).

RMcubic returns an object of class RMmodel.

Chiles, J.-P. and Delfiner, P. (1999) Geostatistics. Modeling Spatial Uncertainty. New York: Wiley.

RMmodel, RFsimulate, RFfit.

RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
##                   RFoptions(seed=NA) to make them all random again

model <- RMcubic()
x <- seq(0, 10, 0.02)
plot(model)
plot(RFsimulate(model, x=x))