https://github.com/cran/fields
Tip revision: c71fb7f6ffa323303affebf0e35a0070faa9c24d authored by Doug Nychka on 10 May 2004, 00:00:00 UTC
version 1.7.2
version 1.7.2
Tip revision: c71fb7f
Wimage.cov.R
"Wimage.cov" <-
function( Y=NULL,ind=NULL, H.obj, find.row=FALSE ){
# local multipcation by H function
Mult.H<-function( u, H.obj){
IND<- H.obj$ind0
u[IND] <- H.obj$H0%*%c(u[IND])
u*H.obj$H1
}
#
# This is a shortcut option to find a single row of the covariance matrix
#
if( find.row){ Y<-1}
#
# if ind is passed fill complete image with the Y subset
#
if(is.null(ind)){
tmp<- Y}
else{
tmp<- matrix(0,nrow=H.obj$m,ncol=H.obj$n)
tmp[ind]<- Y
}
#
#
hold<- Wtransform.image( tmp, cut.min=H.obj$cut.min, inv=TRUE,transpose=TRUE)
#
hold<- Mult.H( hold, H.obj=H.obj) # Note if H not symmetric this should be
# multiplication by transpose.
hold<- Mult.H( hold, H.obj=H.obj)
Wtransform.image( hold, cut.min=H.obj$cut.min, inv=TRUE)
}