https://github.com/cran/fields
Tip revision: 19cf1a7de604fd6967782301036b3eb0e2c5515a authored by Doug Nychka on 03 January 2012, 08:50:12 UTC
version 6.6.3
version 6.6.3
Tip revision: 19cf1a7
Krig.se.grid.test.R
# fields, Tools for spatial data
# Copyright 2004-2011, Institute for Mathematics Applied Geosciences
# University Corporation for Atmospheric Research
# Licensed under the GPL -- www.gpl.org/licenses/gpl.html
library( fields)
# tests of predict.se
# using approximations for conditional simulation on a grid.
#
options( echo=FALSE)
test.for.zero.flag<-1
long.test.flag<- FALSE
data( ozone2)
as.image(ozone2$y[16,], x= ozone2$lon.lat, ncol=24, nrow=20,
na.rm=TRUE)-> dtemp
#
# A useful discretized version of ozone2 data
x<- cbind(dtemp$x[dtemp$ind[,1]], dtemp$y[dtemp$ind[,2]])
y<- dtemp$z[ dtemp$ind]
weights<- dtemp$weights[ dtemp$ind]
Krig( x, y, Covariance="Matern",
theta=1.0, smoothness=1.0, weights=weights) -> out
if(long.test.flag){
# the grid ...
glist<- list( x= dtemp$x, y=dtemp$y)
set.seed( 233)
sim.Krig.grid( out, grid= glist, M=200, extrap=TRUE)-> look
predict.surface.se( out, grid=glist, extrap=TRUE)-> test
look2<- matrix( NA, 20,24)
for( k in 1:24){
for ( j in 1:20){
look2[j,k] <- sqrt(var( look$z[j,k,], na.rm=TRUE))
}
}
test.for.zero( mean( abs(look2- test$z)/test$z), 0, relative=FALSE,
tol=.05, tag="Conditional simulation marginal se for grid")
#
# test for covariances
ind0<- expand.grid( c(1,4,5,10), c(3,4,5,10, 15))
x0<- cbind( glist$x[ind0[,1]], glist$y[ind0[,2]])
look2<- matrix( NA, 200,20)
for( k in 1:20){
look2[,k] <- look$z[ ind0[k,1], ind0[k,2],]}
predict.se( out, x0, cov=TRUE)-> test2
ds<- 1/sqrt(diag(test2))
test3<- diag(ds)%*% test2 %*% diag(ds)
#check plot( diag( test2), diag( var( look2)))
# Another plot to look at plot( c(test3), c(cor(look2)))
hold<-cor(look2)
upper<- col(hold)> row( hold)
dd<- (c(hold)- c(test3))[upper]
test.for.zero( mean( abs(dd)) ,0, relative=FALSE,
tol=.05, tag="Conditional simulation correlations for grid (RMSE) ")
} # end long test block
cat( "all done with grid based se tests", fill=TRUE)
options( echo=TRUE)