WlsStart: Computes Starting Values based on Weighted Least Squares

In GeoModels: Procedures for Gaussian and Non Gaussian Geostatistical (Large) Data Analysis

Computes Starting Values based on Weighted Least Squares

Description

Subroutine called by GeoFit. The function returns appropriate starting values for the composite-likelihood fitting procedure based on weighted least squares.

Usage

WlsStart(coordx, coordy, coordz, coordt, coordx_dyn, corrmodel, data,
         distance, fcall, fixed, grid, likelihood, maxdist, neighb,
         maxtime, model, n, param, parscale, paramrange, radius, start,
         taper, tapsep, type, varest, weighted, copula, X, memdist,
         nosym, p_neighb, thin_method)

Arguments

coordx	A numeric (d \times 2)-matrix or (d \times 3)-matrix. Coordinates on a sphere for a fixed radius radius are passed in lon/lat format expressed in decimal degrees.
coordy	A numeric vector giving 1-dimension of spatial coordinates; optional argument, default is NULL.
coordz	A numeric vector giving 1-dimension of spatial coordinates; optional argument, default is NULL.
coordt	A numeric vector assigning 1-dimension of temporal coordinates.
coordx_dyn	A list of m numeric (d_t \times 2)-matrices containing dynamical (in time) spatial coordinates. Optional argument, default is NULL.
corrmodel	String; the name of a correlation model.
data	A numeric vector or a (n \times d)-matrix or (d \times d \times n)-array of observations.
distance	String; the name of the spatial distance. Default is "Eucl" (euclidean distance).
fcall	String; "fitting" to call the fitting procedure and "simulation" to call the simulation procedure.
fixed	A named list giving the values of the parameters that will be considered as known values.
grid	Logical; if FALSE (default) the data are interpreted as a vector or a (n \times d)-matrix; if TRUE then a (d \times d \times n)-array is considered.
likelihood	String; the configuration of the composite likelihood.
maxdist	Numeric; an optional positive value indicating the maximum spatial distance considered in the composite-likelihood computation.
neighb	Numeric; an optional positive integer indicating the order of neighborhood in the composite likelihood computation.
maxtime	Numeric; an optional positive value indicating the maximum temporal separation considered in the composite-likelihood computation.
model	String; the name of the model.
n	Numeric; number of trials in a binomial random field.
param	A numeric vector of parameter values required in the simulation procedure of random fields.
parscale	A numeric vector with scaling values for improving the maximisation routine.
paramrange	A numeric vector with the range of the parameter space.
radius	Numeric; a value indicating the radius of the sphere when using great circle distance. Default value is the radius of the earth in km (i.e., 6371).
start	A numeric vector (or list) with starting values.
taper	String; the name of the type of covariance matrix. It can be "Standard" (default) or "Tapering" for tapered covariance matrices.
tapsep	Numeric; an optional value indicating the separability parameter in the space-time quasi taper (see Details).
type	String; the type of estimation method.
varest	Logical; if TRUE the estimates variances and standard errors are returned. Default is FALSE.
weighted	Logical; if TRUE the likelihood objects are weighted; see GeoFit.
copula	String; the type of copula. It can be "Clayton" or "Gaussian".
X	Numeric; matrix of spatio(temporal) covariates in the linear mean specification.
memdist	Logical; if TRUE then the distances in the composite likelihood are computed before the optimization.
nosym	Logical; if TRUE symmetric weights are not considered.
p_neighb	Numeric; a value in (0,1] specifying the expected fraction of nearest-neighbor pairs retained through stochastic thinning. If 1 (default), no thinning is applied and all nearest-neighbor pairs are used. If <1, pairs are randomly retained using independent Bernoulli sampling.
thin_method	String; thinning scheme used when p_neighb<1. Default is "iid" (independent Bernoulli thinning).

Details

Internal function called by GeoFit.

Value

A list with a set of useful information in the estimation procedure.

Author(s)

Moreno Bevilacqua, [e-mail], https://sites.google.com/view/moreno-bevilacqua/home, Víctor Morales Oñate, [e-mail], https://sites.google.com/site/moralesonatevictor/, Christian Caamaño-Carrillo, [e-mail], https://www.researchgate.net/profile/Christian-Caamano

See Also

GeoFit.

GeoModels documentation built on April 6, 2026, 5:08 p.m.