R/checkPosteriorsNA.R

In ClusterVAR: Fitting Latent Class Vector-Autoregressive (VAR) Models

checkPosteriorsNA <- function(FZY, K)
{
    iterationReset = FALSE
    if(any(is.na(FZY)))
    { # FZY = ifelse(is.na(FZY), 1/K, FZY)
      # if posterior prob for any person is NA reset that posterior tau_{ij} to a "blind" prior: 1/k
        if(all(is.na(FZY))) stop("All posteriors are NA in one EM-iteration", "\n")
        #cat("\n Warning: Some posteriors are NA in EM-iteration", EMiteration, ", memberships reset \n")
        FZY[which(is.na(FZY))] = 1 / K # Set those p(Y|z_{ik}) that are NA for some person to 1/K
        FZY = t(scale(t(FZY), center = FALSE, scale = rowSums(FZY))) # Scale posteriors so they sum to 1 again
        iterationReset = TRUE
    }

    stopifnot(sum(FZY) != 0) # sum(FZY should equal N)

    invisible(list(FZY = FZY, iterationReset = iterationReset))

}