\name{RFpseudovariogram}
\alias{RFpseudovariogram}
\title{Pseudovariogram}
\description{
 Calculates the theoretical and empirical Pseudovariogram. 
}
\usage{

RFpseudovariogram(model, x, y=NULL, z = NULL, T=NULL, grid, params, distances,
            dim, ..., data, bin=NULL, phi=NULL, theta = NULL,
            deltaT = NULL, vdim=NULL)

}
\arguments{
\item{model,params}{\argModel }
 \item{x}{\argX}
 \item{y,z}{\argYz}
 \item{T}{\argT}
 \item{grid}{\argGrid}
 \item{distances,dim}{\argDistances}
 \item{...}{\argDots}
 \item{data}{\argData}
 \item{bin}{\argBin}
 \item{phi}{\argPhi} 
 \item{theta}{\argTheta} 
 \item{deltaT}{\argDeltaT}
 \item{vdim}{\argVdim}
}
\details{ \command{\link{RFpseudovariogram}} computes the empirical
pseudovariogram for given (multivariate) spatial data. 

%The empirical
% prsepseudovariogram of two random fields \eqn{X}{X} and \eqn{Y}{Y} is given by 
%2 \deqn{\gamma(r):=\frac{1}{2N(r)} \sum_{(t_{i},t_{j})|t_{i,j}=r} (X(t_{i})-X(t_{j}))(Y(t_{i})-Y(t_{j}))}{\gamma(r):=1/2N(r) \sum_{(t_{i},t_{j})|t_{i,j}=r} (X(t_{i})-X(t_{j}))(Y(t_{i})-Y(t_{j}))}
%where \eqn{t_{i,j}:=t_{i}-t_{j}}{t_{i,j}:=t_{i}-t_{j}}, and where \eqn{N(r)}{N(r)} denotes the number of pairs of data points with distancevector 
%\eqn{t_{i,j}=r}{t_{i,j}=r}.

 
 The spatial coordinates \code{x}, \code{y}, \code{z}
   should be vectors. For random fields of
 spatial dimension \eqn{d > 3} write all vectors as columns of matrix x. In
 this case do neither use y, nor z and write the columns in
 \code{gridtriple} notation.

 If the data is spatially located on a grid a fast algorithm based on
 the fast Fourier transformed (fft) will be used.
 As advanced option the calculation method can also be changed for grid
 data (see \command{\link{RFoptions}}.)

}
\value{
 an objects of class
 \command{\link[=RFempVariog-class]{RFempVariog}}. 
}
\references{
  Gelfand, A. E., Diggle, P., Fuentes, M. and Guttorp,
  P. (eds.) (2010) \emph{Handbook of Spatial Statistics.}
  Boca Raton: Chapman & Hall/CRL.
  
  Stein, M. L. (1999) \emph{Interpolation of Spatial Data.}
  New York: Springer-Verlag 
}


\me
 
\seealso{
 \command{\link{RMstable}},
 \command{\link{RMmodel}},
 \command{\link{RFsimulate}},
 \command{\link{RFfit}},
 \command{\link{RFcov}},
 \command{\link{RFmadogram}}.
 \command{\link{RFvariogram}},
}

\examples{\dontshow{StartExample()}
RFoptions(seed=0) ## *ANY* simulation will have the random seed 0; set
##                   RFoptions(seed=NA) to make them all random again


model <- RMbiwm(nudiag=c(1, 2), nured=1, rhored=1, cdiag=c(1, 5), 
                s=c(1, 1, 2))
x <- seq(0, 20, 0.1)
z <- RFsimulate(model, x=x, y=x, n=2)
emp.vario <- RFpseudovariogram(data=z)
plot(emp.vario, model=model)

\dontshow{FinalizeExample()}}

\keyword{spatial}
\keyword{models}