RMcubic {RandomFields}

R Documentation

Cubic Covariance Model

Description

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

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

Usage

RMcubic(var, scale, Aniso, proj)

Arguments

var, scale, Aniso, proj

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

Details

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

Value

RMcubic returns an object of class RMmodel.

Author(s)

Martin Schlather, schlather@math.uni-mannheim.de, https://www.wim.uni-mannheim.de/schlather/

References

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

See Also

RMmodel, RFsimulate, RFfit.

Examples

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))

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