Revision 50d581c9eaaf69a2cd7c85afb79e85d9f8b0ce18 authored by Davor Cubranic on 03 June 2015, 00:00:00 UTC, committed by Gabor Csardi on 03 June 2015, 00:00:00 UTC
1 parent fee4afb
Falternate3.Rd
\name{Falternate3}
\alias{Falternate3}
\title{
Simultaneous coordinate and variogram estimation
}
\description{
Perform simultaneous estimation of coords and exponential or gaussian
variogram by alternating weighted least squares.
}
\usage{
Falternate3(disp, coords, model = 1, a0 = 0.1, t0 = 0.5,
max.iter = 50, max.fcal = 100, alter.lim = 50,
tol = 1e-05, prt = 0, dims = 2, lambda = 0,
ncoords, dev.mon = NULL, verbose = FALSE)
}
\arguments{
\item{disp}{
\eqn{n \times n} dispersion matrix, equal to \eqn{2 - 2 (spatial
correlation matrix)}
}
\item{coords}{
\eqn{n \times 2} coordinate matrix
}
\item{model}{
type of variogram: 1 for exponential or 2 for gaussian
}
\item{a0, t0}{
initial variogram parameter estimates
}
\item{max.iter, max.fcal}{
control parameter for calls to non-linear optimization routines
(same values used in MDS step and in variogram step)
}
\item{alter.lim}{
maximum number of iterations of pairs of alternating calls to
\code{Fmdsfit3} (coordinate estimation) and
\code{\link{Fvariogfit3}} (variogram fitting)
}
\item{tol}{
convergence criterion for coordinate estimates
}
\item{prt}{
not used
}
\item{dims}{
dimension of multi-dimensional scaling
}
\item{lambda}{
smoothing parameter
}
\item{ncoords}{
\eqn{n \times 2} optional initial coordinates to use if not G-plane
}
\item{dev.mon}{
Function to open the graphics device used for plots monitoring the
convergence of objective. If \code{NULL}, monitoring plots will not
be created.
}
\item{verbose}{
if \code{TRUE}, display the results of each iteration to the console
}
}
\details{
This version permits dimension > 2 for scaling.
In the plotting we'll use a plot symbol proportional to the
third coordinate.
}
\value{
A list containing the following named components:
\item{variogfit}{Fitted variogram parameters with new locations}
\item{ncoords}{\eqn{n\times 2} matrix with coordinates of new locations}
}
\note{
This version also passes a smoothing parameter to the optimization.
This parameter probably is not scaled exactly the same as it is
in sinterp and this has not been investigated yet.
}
\section{Warning}{
make sure that coords are scaled reasonably small
before attempting to compute; otherwise matrix inversion is
likely not to work in calculation of bending energy matrix.
}
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