# Falternate3: Simultaneous coordinate and variogram estimation In EnviroStat: Statistical Analysis of Environmental Space-Time Processes

## Description

Perform simultaneous estimation of coords and exponential or gaussian variogram by alternating weighted least squares.

## Usage

 1 2 3 4 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

 disp n \times n dispersion matrix, equal to 2 - 2 (spatial correlation matrix) coords n \times 2 coordinate matrix model type of variogram: 1 for exponential or 2 for gaussian a0, t0 initial variogram parameter estimates max.iter, max.fcal control parameter for calls to non-linear optimization routines (same values used in MDS step and in variogram step) alter.lim maximum number of iterations of pairs of alternating calls to Fmdsfit3 (coordinate estimation) and Fvariogfit3 (variogram fitting) tol convergence criterion for coordinate estimates prt not used dims dimension of multi-dimensional scaling lambda smoothing parameter ncoords n \times 2 optional initial coordinates to use if not G-plane dev.mon Function to open the graphics device used for plots monitoring the convergence of objective. If NULL, monitoring plots will not be created. verbose if 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:

 variogfit Fitted variogram parameters with new locations ncoords n\times 2 matrix with coordinates of new locations

## 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.

## 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.

EnviroStat documentation built on May 2, 2019, 2:32 p.m.