R/M_Index_Age.R

In ctross/SkewCalc: Estimation Of Reproductive Skew

#' M index accounting for diminishing returns to age.
#'
#' @param r A vector of RS values.
#' @param t A vector of ages at death or last census.
#' @param t A vector of ages at first census. Defaults to zero.
#' @return The M index accounting for diminishing returns to age.
#' @examples
#' RS = rpois(100, 5) 
#' Age = rpois(100, 45)
#' M_index_age(RS, Age)

M_index_age = function(r,t,t0=0,Samples=100) {
  if(min(t-t0) <= 0){
  return(NA)
   } else{
     E_Mraw = rep(NA,Samples)
       beta = elast(r,t,t0) 
       tt = t^beta - t0^beta
    for(j in 1: Samples){
      R = sum(r)
      t_hat = tt/sum(tt)
      E_Mraw[j] <- Mraw_index_age(rmultinom(1,R,t_hat),t,t0)
      }
    M = Mraw_index_age(r,t,t0) - mean(E_Mraw)
  return(M)
  }
}