R: RMnonstwm

RMnonstwm {RandomFields} | R Documentation

## RMnonstwm

### Description

The non-stationary Whittle-Matern model C is given by

C(x, y)=Γ(μ) Γ(ν(x))^{-1/2} Γ(ν(y))^{-1/2} W_{μ} (|x-y|)

where μ = [ν(x) + ν(y)]/2, and ν must a positive function.

W_{μ} is the covariance of the `RMwhittle` model or the `RMmatern` model and

### Details

The non-stationary Whittle-Matern models are obtained by the respective stationary model, replacing the real-valued argument for `nu` by a non-negative function.

### Note

It cannot be checked whether `nu` only takes positive number. So the responsibility is completely left to the user.

### Author(s)

Martin Schlather, schlather@math.uni-mannheim.de

### References

- Stein, M. (2005) Nonstationary Spatial Covariance Functions. Tech. Rep., 2005

### See Also

`RMwhittle`, `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

    x <- seq(-1.2, 1.2, len=50)
    model <- RMwhittle(nu=RMgauss())

    z <- RFsimulate(model=model, x, x, n=4)
    plot(z)

[Package RandomFields version 3.1.50 Index]