RMma: Ma operator

In RandomFields: Simulation and Analysis of Random Fields

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.

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))

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