R/solow2005.R

In Clara-Casabona/ExtinctModels: Models to infer the date of extinction

#' Solow2005.eq7.fun
#'
#' @param dd
#'
#' @return
#' @export
#'
#' @examples
Solow2005.eq7.fun <-
  function(dd){
    names(dd) <-  c("yrs", "sights")
    dd$year   <-  dd$yrs-min(dd$yrs)
    sSolow    <-  sum(dd$year*dd$sights)
    tn        <-  max(dd[(dd$sights>0),]$year)
    TSolow    <-  max(dd$year)
    n         <-  sum(dd$sights)
    y         <-  tn/sSolow
    dummy     <-  0
    if(floor(1/y)>0){

      for(i in seq(floor(1/y))){

        dummy<-dummy+(-1)^(i-1)*choose(n,i)*(1-i*y)^(n-1)
      }
    }

    Fs1    <-  1-dummy
    y      <-  TSolow/sSolow
    dummy  <-  0

    if(floor(1/y)>0){

      for(i in seq(floor(1/y))){

        dummy<-dummy+(-1)^(i-1)*choose(n,i)*(1-i*y)^(n-1)
      }
    }

    Fs2 <- 1-dummy
    res <- Fs1/Fs2
    return(res)
  }