@adrianperea/genie.js/lib/ga/crossover.js

A highly flexible, data-agnostic, and UI-independent Genetic Algorithm Library

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.crossover = crossover;
exports.onepoint = onepoint;
exports.multipoint = multipoint;
exports.uniform = uniform;

var _random = require("../utils/random");

function crossover(parentOne, parentTwo, crossoverFunc) {
  var childDna = _getChildDna(parentOne, parentTwo, crossoverFunc);

  return new parentOne.constructor(childDna);
}

function _getChildDna(parentOne, parentTwo, crossoverFunc) {
  var childDna = parentOne.dna.map(function (parentOneChromosome, i) {
    var parentTwoChromosome = parentTwo.dna[i];
    var genes = crossoverFunc(parentOneChromosome, parentTwoChromosome);
    return parentOneChromosome.copyWithGenes(genes);
  });
  return childDna;
}

function onepoint(chromosomeOne, chromosomeTwo) {
  var point = (0, _random.randBetween)(0, chromosomeOne.length);
  return _onepoint(chromosomeOne, chromosomeTwo, point);
}

function _onepoint(chromosomeOne, chromosomeTwo, point) {
  var childGenes = chromosomeOne.genes.map(function (geneOne, i) {
    var geneTwo = chromosomeTwo.genes[i];
    return i < point ? geneOne : geneTwo;
  });
  return childGenes;
}

function multipoint(chromosomeOne, chromosomeTwo) {
  var pointOne = (0, _random.randBetween)(0, chromosomeOne.length);
  var pointTwo = (0, _random.randBetween)(pointOne, chromosomeOne.length);
  return _multipoint(chromosomeOne, chromosomeTwo, pointOne, pointTwo);
}

function _multipoint(chromosomeOne, chromosomeTwo, pointOne, pointTwo) {
  var childGenes = chromosomeOne.genes.map(function (geneOne, i) {
    var geneTwo = chromosomeTwo.genes[i];
    return i < pointOne || i >= pointTwo ? geneOne : geneTwo;
  });
  return childGenes;
}

function uniform(chromosomeOne, chromosomeTwo) {
  var probabilities = Array(chromosomeOne.length).fill(null).map(function () {
    return Math.random();
  });
  return _uniform(chromosomeOne, chromosomeTwo, probabilities);
}

function _uniform(chromosomeOne, chromosomeTwo, probabilities) {
  var childGenes = chromosomeOne.genes.map(function (geneOne, i) {
    var geneTwo = chromosomeTwo.genes[i];
    var probability = probabilities[i];
    return probability < 0.5 ? geneOne : geneTwo;
  });
  return childGenes;
}