PointsUpdatemp {adlift}R Documentation

PointsUpdatemp

Description

This function performs the update lifting step using a given configuration of neighbours and boundary handling.

Usage

PointsUpdatemp(X, coeff, nbrs, newnbrs, index, remove, pointsin, weights, lengths,
 updateboundhandl)

Arguments

X the vector of grid values.
coeff the vector of detail and scaling coefficients at that step of the transform.
nbrs the indices (into X) of the neighbours to be used in the lifting step.
newnbrs as nbrs, but repeated according to the multiple point structure of the grid.
index the indices into pointsin of nbrs, the neighbours of remove.
remove the index (into X) of the point to be removed.
pointsin The indices of gridpoints still to be removed.
weights the prediction weights obtained from the regression in the prediction step of the transform.
lengths the vector of interval lengths at the present step of the transform (to be updated).
updateboundhandl boundary handling in the update step. Possible values are "reflect", "stop" and "add". If the point to be removed is at the boundary, "reflect" updates the neighbour interval to be symmetrical about its gridpoint; "stop" extends its length up until the boundary gridpoint; and "add" increases its interval length by the interval length associated to the removed boundary point.

Details

The procedure performs a minimum norm update lifting step. Firstly the interval lengths are updated using the coefficients obtained. Secondly, the scaling and detail coefficient list is modified using the new interval lengths.

Value

coeff vector of (modified) detail and scaling coefficients to be used in the next step of the transform.
lengths the vector of interval lengths after the update step of the transform.
r the index into pointsin of remove.
N length(pointsin).
weights The regression coefficients used in prediction.
alpha the update weights used to update lengths and coeff.

Author(s)

Matt Nunes (matt.nunes@bristol.ac.uk), Marina Popa (Marina.Popa@bristol.ac.uk)

See Also

AdaptNeighmp, AdaptPredmp, CubicPredmp, fwtnpmp, LinearPredmp, QuadPredmp, UndoPointsUpdatemp

Examples

#read in data with multiple values...

data(motorcycledata)
times<-motorcycledata$time
accel<-motorcycledata$accel

short<-adjustx(times,accel,"mean")
X<-short$sepx
coeff<-short$sepx
g<-short$g

coefflist<-list()
for (i in 1:length(g)){
coefflist[[i]]<-accel[g[[i]]]
}

I<-intervals(X,"reflect")
l<-lengthintervals(X,I$intervals,neighbours=2,closest=TRUE)
lengths<-l$lengths

#work out neighbours of point to be removed (31)

out<-getnbrs(X,31,order(X),2,TRUE)
nbrs<-out$n

nbrs

newnbrs<-NULL
for (i in 1:length(nbrs)){
newnbrs<-c(newnbrs,rep(nbrs[i],times=length(g[[nbrs[i]]])))
}

#work out repeated neighbours using g...
newnbrs

p<-AdaptNeighmp(order(X),X,coefflist,coeff,nbrs,newnbrs,31,TRUE,2,"ave",g)

nbrs<-p$newinfo[[3]]
nbrs
newnbrs<-NULL
for (i in 1:length(nbrs)){
newnbrs<-c(newnbrs,rep(nbrs[i],times=length(g[[nbrs[i]]])))
}
newnbrs

coefflist[[31]]<-p$results[[6]][31]

u<-PointsUpdatemp(X,coefflist,p$newinfo[[3]],newnbrs,p$newinfo[[4]],31,order(X),p$results[[4]]
,lengths,"add")
#
#and here is the updated coefficient list...
u$coeff

[Package adlift version 0.9-6 Index]