Learn R Programming

GeoModels (version 2.2.2)

StartParam: Initializes the Parameters for Estimation Procedures

Description

Subroutine called by the fitting procedures. The procedure initializes the parameters for the fitting procedure.

Usage

StartParam(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, typereal, weighted, copula, X, memdist, nosym,
           p_neighb, thin_method)

Value

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

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). See the Section Details.

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. See the Section Details for more information.

maxtime

Numeric; an optional positive value indicating the maximum temporal lag considered in the composite-likelihood computation.

model

String; the density associated to the likelihood objects. "Gaussian" is the default.

n

Numeric; number of trials for binomial random fields.

param

A numeric vector of parameter values required in the simulation procedure of random fields.

parscale

A numeric vector of scaling factors to improve the maximizing procedure; see optim.

paramrange

A numeric vector of parameter ranges; see optim.

radius

Numeric; the radius of the sphere in the case of lon-lat coordinates. The default is 6371, the radius of the earth.

start

A named list with the initial values of the parameters that are used by the numerical routines in the maximization procedure.

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 adaptive taper (see Details).

type

String; the type of likelihood objects. Temporary value set to "WLeastSquare" (weighted least-square) in order to compute starting values.

typereal

String; the real type of likelihood objects. See GeoFit.

weighted

Logical; if TRUE the likelihood objects are weighted; see GeoFit.

copula

String; the type of copula.

X

Numeric; matrix of space-time covariates.

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 WlsStart.