RFcrossvalidate {RandomFields}R Documentation

Fitting model parameters to spatial data (regionalised variables) and to linear (mixed) models

Description

The function estimates arbitrary parameters of a random field specification with various methods. Currenty, the model to be fitted can be

The fitting of max-stable random fields and others has not been implemented yet.

Usage

RFcrossvalidate(model, x, y = NULL, z = NULL, T = NULL, grid=NULL, data,
 lower = NULL, upper = NULL, method="ml",
 users.guess = NULL,
 distances = NULL, dim, optim.control = NULL,transform = NULL,
 full = FALSE, ...)

Arguments

model, x, y, z, T, grid, data,lower, upper, users.guess, distances, dim, optim.control, transform, ...

see RFfit

method

Single method to be used for estimating, either one of the methods or one of the sub.methods see RFfit

full

logical. if TRUE then crossvalidatiaon is also performed for intermediate models used in RFfit (if any).

Value

An object of the class "RFcrossvalidate" which is a list with the following components, cf. xvalid in the package geoR :

data

the original data.

predicted

the values predicted by cross-validation.

krige.var

the cross-validation prediction variance.

error

the differences data - predicted value.

std.error

the errors divided by the square root of the prediction variances.

p

In contrast to geoR the p-value is returned, i.e. the probability that a difference with absolute value larger than the absolute value of the actual difference is observed.

A method for summary returns summary statistics for the errors and standard errors similar to geoR.

If cross_refit = TRUE and detailed_output = TRUE the returned object also constains a fitted which is a list of fitted models.

Methods

print

prints the summary

summary

gives a summary

Note

An important option is cross_refit that determines whether the model is refitted for each location left out. Default is FALSE. See also RFoptions.

Note

This function does not depend on the value of RFoptions()$PracticalRange. The function RFcrossvalidate always uses the standard specification of the covariance model as given in RMmodel.

Author(s)

Martin Schlather, schlather@math.uni-mannheim.de http://ms.math.uni-mannheim.de/de/publications/software

References

See Also

RFratiotest RFfit RMmodel, RandomFields, weather.

Examples

RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
##                   RFoptions(seed=NA) to make them all random again




## currently disabled!
[Package RandomFields version 3.1.50 Index]