[R-sig-Geo] help in CompRandFld package

[Saman Monfared]

Dear All.
I Try to use CompRandFld package for Spatio-temporal modeling of Irish
wind data.
I write Irish wind data in txt format. I calculate times in days
((year*365)+(month*30)+day)
and saved in a coloumn with name times. I want fit a spatio-temporal
covariance  like gneiting
model.

A part of My program is :


rm(list=ls())
library(CompRandFld)
library(RandomFields)
dd<-read.table("wind.txt",header=T)
names(dd)
x <- dd$x
y <- dd$y
mean <- mean(dd$values)
sill <- 1
nugget <- 0
scale <- 3
set.seed(331)
# Define the temporal sequence:
times <- seq(1,10,1)
# Simulation of a spatio-temporal Gaussian random field:
data <- RFsim(x, y, times, corrmodel="gneiting",
param=list(mean=mean,scale_s=3,scale_t=3,sill=sill,
nugget=0,power_s=1,power_t=1,sep=0.2))$data
************************************************
Error in chol.default(varcov) :
  the leading minor of order 11 is not positive definite.

Please help me.


-- 

Saman Monfared
Msc Student,
Department of Statistics, Shiraz University,
Shiraz 71454, Iran
Email: Samanmonfared1 at gmail.com

Tel: +98 917 5305167