R/equitability.R

In diversityArch: Computes Diversity Indices for Archaeological Data

#' @title Equitability. J Pielou index
#'
#' @description Computes J Pielou index know as equitability
#'
#' @param x Vector of dimension S (number of species) with the number of individuals observed in each species, or the distribution frequencies of species. NA values are allowed.
#'
#' @return Equitability. J Pielou index.
#'
#' @seealso \link{shannon}
#'
#' @references
#' Arnaud Barat, Andreu Sansó, Maite Arilla-Osuna, Ruth Blasco, Iñaki Pérez-Fernández, Gabriel Cifuentes-Alcobenda, Rubén Llorente, Daniel Vivar-Ríos, Ella Assaf, Ran Barkai, Avi Gopher, & Jordi Rosell-Ardèvol (2026) <doi:10.1007/s10816-026-09802-3>.
#'
#' @examples
#' data(Qesem_s)
#' equitability(Qesem_s$HU)
#'
#' @export
equitability <- function(x){               # J (Pielou)
  x <- check_x(x)
  return(shannon(x)/log(length(x)))
}