RMpower: Power operator for Variograms and Covariance functions

Description Usage Arguments Details Value References See Also Examples

View source: R/RMmodels.R

Description

RMpower yields a variogram or covariance model from a given variogram or covariance model. The variogram gamma of the model is given by

gamma=phi^alpha

if phi is a variogram model. The covariance C of the model is given by

C(h) = phi(0)-(phi(0)-phi(h))^alpha

if phi is a covariance model.

Usage

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RMpower(phi, alpha, var, scale, Aniso, proj)

Arguments

phi

a valid RMmodel; either a variogram model or a covariance model

alpha

a numerical value in the interval [0,1]

var,scale,Aniso,proj

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

Details

If γ is a variogram, then γ^α is a valid variogram for α in the interval [0,1].

Value

RMpower returns an object of class RMmodel.

References

Schlather, M. (2012) Construction of covariance functions and unconditional simulation of random fields. In Porcu, E., Montero, J. M., Schlather, M. Advances and Challenges in Space-time Modelling of Natural Events, Springer, New York.

See Also

RMmodel, RFsimulate, RFfit.

Examples

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

model <- RMpower(RMgauss(), alpha=0.5)
x <- seq(0, 10, 0.02)
plot(model)
plot(RFsimulate(model, x=x))

RandomFields documentation built on Jan. 19, 2022, 1:06 a.m.