R/operator.EARecombinatorOnePointCrossover.R

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

#' @title
#' One-point crossover recombinator.
#'
#' @description
#' The one-point crossover recombinator is defined for float and binary
#' representations. Given two real-valued/binary vectors of length n, the
#' selector samples a random position i between 1 and n-1. In the next step
#' it creates two children. The first part of the first child contains of the
#' subvector from position 1 to position i of the first parent, the second part
#' from position i+1 to n is taken from the second parent. The second child
#' is build analogously.
#' If the parents are list of real-valued/binary vectors, the procedure described
#' above is applied to each element of the list.
#'
#' @param inds [\code{list}]\cr
#'   Parents, i.e., list of exactly two numeric or binary vectors of equal length.
#' @return [\code{list}]
#' @family recombinators
#' @export
EARecombinatorOnePointCrossover = function() {
  EARecombinator$new(
    name = "One-point crossover",
    representations = c("binary", "real"),
    params = list(),
    n.parents = 2L,
    n.children = 2L,
    fun = function(inds) {
      n = length(inds[[1L]])

      # recombinate sub genes
      parent1 = inds[[1L]]
      parent2 = inds[[2L]]

      idx = sample(seq(n - 1), size = 1L)
      # back part from other parent
      child1 = parent2
      child2 = parent1
      # front part from "their" parent
      child1[1:idx] = parent1[1:idx]
      child2[1:idx] = parent2[1:idx]

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