lmeBM {covBM}

lmeBM

Description

This function is a wrapper for lme.formula that allows Brownian motion, fractional Brownian motion or integrated Ornstein-Uhlenbeck components to be included in linear mixed models, with related parameter estimates and confidence intervals returned in their natural parameterisation.

Usage

lmeBM(fixed, data, random, covariance = NULL, method = c("REML", "ML"),
  control = list(), keep.data = TRUE)

Arguments

fixed

This is as specified for lme.formula.

data

This is as specified for lme.formula.

random

This is as specified for lme.formula.

covariance

An optional corStruct object describing the within-group covariance structure. In addition to those available in nlme, covBM can be used to incorporate a Brownian motion component, covFracBM can be used to incorporate a fractional Brownian motion component and covIOU can be used to incorporate an integrated Ornstein-Uhlenbeck process in relation to a continuous variable.

method

This is as specified for lme.formula.

control

This is as specified for lme.formula.

keep.data

This is as specified for lme.formula.

Value

An object of class "lme" representing the linear mixed effects model fit.

Examples

BMmodel<-lmeBM(sqrtcd4~t, data=cd4, random=~t|newpid, covariance=covBM(form=~t|newpid),
							method="ML", control=list(opt="link{nlm}"))