Nothing
"matern.specdens" <-
function(omega,param,d=2){
# spectral density for Matern correlation function
# param should be in the form of (correlation scale, differentiability) (often called rho,nu)
# this uses the form of the Matern in which rho and nu interact minimally, namely,
# R(\tau)=\frac{1}{\Gamma(\nu) 2^(\nu-1)} (\frac{2\sqrt{nu} tau}{\rho})^\nu K_{\nu}(\frac{2\sqrt{nu} tau}{\rho}) - see Stein (1999; p. 50), Interpolation of Spatial Data: Some Theory for Kriging
if(is.vector(omega) || (is.matrix(omega) && min(dim(omega))==1) || (is.array(omega) && length(dim(omega))==1)){
if(d==2 && length(omega)!=2){
warning("You specified d=2 but gave a vector of frequencies; interpreting as d=1.\n")
d=1
omega=matrix(c(omega),ncol=1)
}
if(d==2 && length(omega)==2){
warning("Assuming a single two-dimensional frequency.\n")
omega=matrix(omega,nrow=1,ncol=d)
}
} else{
if(!(
(is.matrix(omega) && ncol(omega)==2) ||
(is.array(omega) && length(dim(omega))==2 && dim(omega)[2]==2) ||
(is.data.frame(omega) && ncol(omega)==2)
)){
stop("omega must be a vector or a two-dimensional matrix/array")
}
}
if(is.matrix(omega) && min(dim(omega))>1 && d==1){
stop("omega is a matrix with more than one row, but you specified d=1")
}
if(length(param)!=2 || param[1]<=0 || param[2]<=0){
stop("Matern spectral density requires two positive parameters")
}
rho=param[1]
nu=param[2]
if(d==1){
omegaTomega=omega*omega
} else{
omegaTomega=omega[,1]*omega[,1]+omega[,2]*omega[,2]
}
exp(lgamma(nu+d/2)+nu*log(4*nu)-(d/2)*log(pi)-lgamma(nu)-2*nu*log(rho*pi)-(nu+d/2)*log(4*nu/(pi*pi*rho*rho)+omegaTomega))
}
Any scripts or data that you put into this service are public.
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.