| Specific {RandomFields} | R Documentation |
This model determines that the (Gaussian) random field should be modelled by a particular method that is specific to the given covariance model.
RPspecific(phi, boxcox)
phi |
object of class |
boxcox |
the one or two parameters of the box cox transformation.
If not given, the globally defined parameters are used.
see |
RPspecific is used for specific algorithms or specific features
for simulating certain covariance functions
RMplus
is able to simulate separately
the fields given by its summands. This is necessary, e.g., when
a RMtrend is involved.
RMmult
for Gaussian random fields only.
RMmult simulates the random fields
of all the components and multiplies them. This is repeated
several times and averaged.
RMS
Then, for instance,
sqrt(var) is multiplied onto the (Gaussian) random
fields after the field has been simulated.
Hence, when var is random, then, for each realisation
of the Gaussian field (for n>1 in RFsimulate)
a new realisation of var is used.
Further, new coordinates are created where the old coordinates
have been devided by the scale and/or multiplied with the
Aniso matrix or a projection has been performed.
RPspecific(RMS()) is called internally when
the user wants to simulate Anisotropic fields with
isotropic methods, e.g. RPtbm.
Note that RPspecific applies only to the first model or
operator in argument phi.
RPspecific returns an object of class RMmodel
Martin Schlather, schlather@math.uni-mannheim.de
Schlather, M. (1999) An introduction to positive definite functions and to unconditional simulation of random fields. Technical report ST 99-10, Dept. of Maths and Statistics, Lancaster University.
RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
## RFoptions(seed=NA) to make them all random again
## example for implicite use
model <- RMgauss(var=10, s=10) + RMnugget(var=0.1)
plot(model)
plot(RFsimulate(model=model, 0:10, 0:10, n=4))
## The following function shows the internal structure of the model.
## In particular, it can be seen that RPspecific is applied to RMplus.
RFgetModelInfo(level=0, which="internal")
## example for explicite used
model <- RPspecific(RMS(var=unif(min=0, max=10), RMgauss()))
x <- seq(0,10,0.02)
n <- 10
for (i in 1:n) {
readline(paste("Simulation no.", i, ": press return", sep=""))
plot(RFsimulate(model, x=x, n=6, seed=i), ylim=c(-5,5))
}