R/mymaxlik.R

In msears8/PROJ1.STATS: Introductory Package

#' @title Max liklihood function
#' @description A function that produces a plot fo maximum liklihood probability
#' @param lfun function to be performed
#' @param x number of successes (Binomial)
#' @param param number of trials
#' @param ... other parameters to introduce in the function
#'
#' @return a plot of the maximum liklihood probability p for the number of
  #' successes y in the amount of trials
#' @export
#'
#' @examples
#' mymaxlik(x=c(9,9,1,9,9,9),param=seq(0,1,length=1000),lfun=logbin,
  #' xlab=expression(pi),main="Binomial",cex.main=2)

mymaxlik=function(lfun,x,param,...){
  np=length(param)
  z=outer(x,param,lfun)
  y=apply(z,2,sum)

  plot(param,y,col="Blue",type="l",lwd=2,...)

  i=max(which(y==max(y)))
  abline(v=param[i],lwd=2,col="Red")

  points(param[i],y[i],pch=19,cex=1.5,col="Black")
  axis(3,param[i],round(param[i],2))

  ifelse(i-3>=1 & i+2<=np, slope<-(y[(i-2):(i+2)]-y[(i-3):(i+1)])/(param[(i-2):(i+2)]-param[(i-3):(i+1)]),slope<-"NA")
  return(list(i=i,parami=param[i],yi=y[i],slope=slope))
}