mle.R

require(stats4) # 3.3.1

nloglik_lnormal <- function(lmu, lsigma){
  # df columns: b.u(pper border), b.l(ower border), n(umber of households)
  return(-sum(with(temp,
                   n*log(plnorm(b.u, meanlog=lmu, sdlog = exp(lsigma))
                         - plnorm(b.l, meanlog=lmu, sdlog = exp(lsigma))
                   )
                   -log(n))
  ) - sum(log(1:sum(df$n)))
  )
}

result.ln <- list()
for( a in df$region %>% unique()){
  print(a)
  temp <- filter(df, region == a) %>% select(b.u, b.l, n)
  result.ln[[a]] <- mle(nloglik_lnormal, start=list(lmu=log(350), lsigma=1))
}

return lsigma in logarithm