LKrigSetupAlpha {LatticeKrig} | R Documentation |
Creates the alpha parameter list in LatticeKrig covariance.
Description
This function is called by LKrigSetup
and
creates the list for the alpha parameters based on the information
from the call to LKrigSetup
and additional information and
conditions related to the geometry.
Usage
LKrigSetupAlpha(object, ...)
## Default S3 method:
LKrigSetupAlpha(object, ...)
LKFindAlphaVarianceWeights(x1, LKinfo, level)
Arguments
x1 |
Locations to evaluate the alpha weights. |
LKinfo |
An LKinfo object that is usually created by LKrigSetup. |
level |
Level of the multiresolution. |
object |
The partial LKinfo object created within |
... |
Any additional arguments to this method |
Details
The main function of this method is to fill in the sequence of alpha values
for a parametric model and convert those values to a list instead of a vector. In the case that the scalar nu
is supplied it is used to create the list according to:
alpha <- 2**(-2 * (1:nlevel) * nu) alpha <- alpha/sum(alpha) as.list( alpha)
Value
A list with nlevel
components each representing the alpha values
at that level. In the simplest case a vector of alpha values is converted to
a list.
LKinfo<- LKrigSetup( x, alpha=c( 1,.2,.01), nlevel=3, a.wght=4.5, NC= 3) LKrigSetupAlpha( LKinfo) [[1]] [1] 1 [[2]] [1] 0.2 [[3]] [1] 0.01
The lower level function LKFindAlphaVarianceWeights
is used to supply weights as in the default model but also evaluate the weights at arbitrary locations. This second role is part of specifying a nonstationary model where the weights vary over the spatial domain.
Author(s)
Doug Nychka
See Also
LKrigSetup
, LKrigSetupAwght
,
LKrigSAR
, LKrig
Examples
# an x that is just the limits of the domain
x<- cbind( c(0,1), c(0,1))
LKinfo<- LKrigSetup( x, alpha=c( 1,.2,.01),
nlevel=3, a.wght=4.5, NC= 3)
alphaList<- LKrigSetupAlpha( LKinfo)
LKinfo<- LKrigSetup( x, nu=1, nlevel=4, a.wght=4.5, NC= 4)
alphaList<- LKrigSetupAlpha( LKinfo)