R/effe01.R

In CUB: A Class of Mixture Models for Ordinal Data

#' @title Auxiliary function for the log-likelihood estimation of CUB models
#' @description Compute the opposite of the scalar function that is maximized when running 
#' the E-M algorithm for CUB models with covariates for the feeling parameter.
#' @aliases effe01
#' @usage effe01(gama, esterno01, m)
#' @param gama Vector of the starting values of the parameters to be estimated
#' @param esterno01 A matrix binding together the vector of the posterior probabilities
#' that each observation has been generated by the first component distribution of the mixture, 
#' the ordinal data and the matrix of the selected covariates accounting for an intercept term
#' @keywords internal 
#' @details It is called as an argument for optim within CUB function for models with covariates for
#' feeling or for both feeling and uncertainty


effe01 <-
function(gama,esterno01,m){  
  ttau<-esterno01[,1]
  ordd<-esterno01[,2]
  covar<-esterno01[,3:ncol(esterno01)]
  return(sum(ttau*((ordd-1)*(covar%*%gama)+(m-1)*log(1+exp(-covar%*%gama)))))
}