lgcp (version 1.3-3)

lgcpInits: lgcpInits function

Description

A function to declare initial values for a run of the MCMC routine. If specified, the MCMC algorithm will calibrate the proposal density using these as provisional estimates of the parameters.

Usage

lgcpInits(etainit = NULL, betainit = NULL)

Arguments

etainit

a vector, the initial value of eta to use

betainit

a vector, the initial value of beta to use

Value

• an object of class lgcpInits used in the MCMC routine.

Details

It is not necessary to supply intial values to the MCMC routine, by default the functions lgcpPredictSpatialPlusPars, lgcpPredictAggregateSpatialPlusPars, lgcpPredictSpatioTemporalPlusPars and lgcpPredictMultitypeSpatialPlusPars will initialise the MCMC as follows. For eta, if no initial value is specified then the initial value of eta in the MCMC run will be the prior mean. For beta, if no initial value is specified then the initial value of beta in the MCMC run will be estimated from an overdispersed Poisson fit to the cell counts, ignoring spatial correlation. The user cannot specify an initial value of Y (or equivalently Gamma), as a sensible value is chosen by the MCMC function.

A secondary function of specifying initial values is to help design the MCMC proposal matrix, which is based on these initial estimates.

See Also

minimum.contrast, minimum.contrast.spatiotemporal, chooseCellwidth, getpolyol, guessinterp, getZmat, addTemporalCovariates, lgcpPrior, CovFunction, lgcpPredictSpatialPlusPars, lgcpPredictAggregateSpatialPlusPars, lgcpPredictSpatioTemporalPlusPars, lgcpPredictMultitypeSpatialPlusPars

Examples

INITS <- lgcpInits(etainit=log(c(sqrt(1.5),275)), betainit=NULL)