RMbr2eg: Transformation from Brown-Resnick to Gauss

Description Usage Arguments Details Value References See Also Examples

View source: R/RMmodels.R

Description

This function can be used to model a max-stable process based on a binary field, with the same extremal correlation function as a Brown-Resnick process

C_{eg}(h) = 1 - 2 (1 - 2 Φ(√{γ(h) / 2}) )^2

Here, Φ is the standard normal distribution function, and γ is a semi-variogram with sill

4(erf^{-1}(1/√ 2))^2 = 2 * [Φ^{-1}( [1 + 1/√ 2] / 2)]^2 = 4.425098 / 2 = 2.212549

Usage

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RMbr2eg(phi, var, scale, Aniso, proj)

Arguments

phi

covariance function of class RMmodel.

var,scale,Aniso,proj

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

Details

RMbr2eg
The extremal Gaussian model RPschlather simulated with RMbr2eg(RMmodel()) has tail correlation function that equals the tail correlation function of Brown-Resnick process with variogram RMmodel.

Note that the reference paper is based on the notion of the (genuine) variogram, whereas the package RandomFields is based on the notion of semi-variogram. So formulae differ by factor 2.

Value

object of class RMmodel

References

See Also

maxstableAdvanced, RMbr2bg, RMmodel, RMm2r, RPbernoulli, RPbrownresnick, RPschlather.

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 <- RMexp(var=1.62 / 2) 
binary.model <- RPbernoulli(RMbr2bg(model))
x <- seq(0, 10, 0.05)

z <- RFsimulate(RPschlather(binary.model), x, x)
plot(z)

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