R/loglikcubecsi.R

In CUB: A Class of Mixture Models for Ordinal Data

#' @title Log-likelihood function of CUBE model with covariates only for feeling
#' @aliases loglikcubecsi
#' @description 
#' Compute the log-likelihood function of a CUBE model for ordinal data with subjects' 
#' covariates only for feeling.
#' @usage loglikcubecsi(m, ordinal, W, pai, gama, phi)
#' @keywords internal
#' @param m Number of ordinal categories
#' @param ordinal Vector of ordinal responses
#' @param W Matrix of covariates for explaining the feeling component
#' @param pai Uncertainty parameter
#' @param gama Vector of parameters for the feeling component, with length 
#' equal to NCOL(W) + 1 to account for an intercept term (first entry of gama)
#' @param phi Overdispersion parameter
#' @seealso internal


loglikcubecsi <-
function(m,ordinal,W,pai,gama,phi){
  
  if (is.factor(ordinal)){
    ordinal<-unclass(ordinal)
  }
  W<-as.matrix(W)
  csivett<-logis(W,gama)
  probi<-pai*(betabinomialcsi(m,ordinal,csivett,phi)-1/m)+1/m
  return(sum(log(probi)))
}