R: Ma operator

RMma {RandomFields} | R Documentation

## Ma operator

### Description

`RMma` is a univariate stationary covariance model depending on a univariate stationary covariance model. The corresponding covariance function only depends on the difference h between two points and is given by

C(h) = (θ / (1 - (1-θ) * φ(h)))^α

### Usage

    RMma(phi, alpha, theta, var, scale, Aniso, proj)

### Arguments

`phi` | a stationary covariance `RMmodel`.
`alpha` | a numerical value; positive
`theta` | 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.

### Value

`RMma` returns an object of class `RMmodel`

### Author(s)

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

### References

- Ma, C. (2003) Spatio-temporal covariance functions generated by mixtures. Math. Geol., 34, 965-975.

### 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 <- RMma(RMgauss(), alpha=4, theta=0.5)
    x <- seq(0, 10, 0.02)
    plot(model)
    plot(RFsimulate(model, x=x))

[Package RandomFields version 3.1.50 Index]