R/BetaupdateCov.R

In SAcmu/LLSM: Package to Fit Longitudinal Latent Space Model

BetaupdateCov <-
function(Intercept,llikAll,MuBeta,VarBeta,tune,acc,Y,Z,TT,X,Beta){
    #propose new value for intercept
    BetaNew = Beta
    for(kk in 1:length(Beta)){
        BetaNew[kk] = Beta[kk] + tune[kk]*rnorm(1,0,1)
    #compute loglikelihood at proposed value
        llikNew = sum((sapply(1:TT,function(xx){
            likelihoodCov(Y[[xx]],Z[[xx]],Intercept,X[[xx]],BetaNew)})))
    #log prior at current value
    priorOld = betaprior(Beta[kk], MuBeta, VarBeta)
    #log prior at new value
    priorNew = betaprior(BetaNew[kk],MuBeta,VarBeta)
    #logratio
    logratio = llikNew - llikAll + priorNew - priorOld
    if(logratio > log(runif(1,0,1))){
        Beta[kk] = BetaNew[kk]
        acc[kk] = acc[kk] + 1
        llikAll = llikNew
    }else{BetaNew[kk]=Beta[kk]}
    }
    return(list(Beta=Beta,acc = acc,llikAll = llikAll))
}