R/operator.EARecombinatorUniformCrossover.R

In jakobbossek/ecr3: Evolutionary Computation in R - Version 3

#' @title
#' Uniform crossover recombinator.
#'
#' @description
#' Produces two child individuals. The i-th gene is from parent1 with probability
#' \code{p} and from parent2 with probability \code{1-p}.
#'
#' @param inds [\code{list}]\cr
#'   Parents, i.e., list of exactly two numeric or binary vectors of equal length.
#' @param p [\code{numeric(1)}]\cr
#'   Probability to select gene from parent1.
#' @return [\code{list}]
#' @family recombinators
#' @export
EARecombinatorUniformCrossover = function(p = 0.5) {
  EARecombinator$new(
    name = "Uniform crossover",
    representations = c("binary", "real"),
    params = list(p = p),
    n.parents = 2L,
    n.children = 2L,
    fun = function(inds, p = 0.5) {
      n = length(inds[[1L]])

      mask = (runif(n) < p)

      # extract parents
      parent1 = inds[[1L]]
      parent2 = inds[[2L]]

      # back part from other parent
      child1 = parent1
      child2 = parent2

      # front part from "their" parent
      child1[mask] = parent2[mask]
      child2[mask] = parent1[mask]

      return(list(child1, child2))
    }
  )
} # EARecombinatorUniformCrossover