Eugenics

Eugenics is an immutable typescript library for genetic algorithms. It is designed to be used in a functional programming style, returning new objects instead of mutating existing ones for libraries like React or Redux.

The library has been inspired by Python's DEAP library.

Installation

npm install eugenics

Usage

Knapsack problem

Here's an example implementation of the knapsack problem using eugenics.

import { crossTwoPoint, mutFlipBit, selTournament, evolveSimple } from 'eugenics';

const generateProblem = n => {
	const weights = [];
	const values = [];
	for (let i = 0; i < n; i++) {
		weights.push(Math.ceil(Math.random() * 10 + 5));
		values.push(Math.ceil(Math.random() * 10 + 5));
	}
	return { weights, values };
};
const max_weight = 40;
const problem = generateProblem(10);

const fitness = (individual: boolean[]) => {
	let weight = 0;
	let value = 0;
	for (let i = 0; i < individual.length; i++) {
		if (individual[i]) {
			weight += problem.weights[i];
			value += problem.values[i];
		}
	}
	if (weight > max_weight) {
		return 0;
	}
	return value;
};

const population = Array.from({ length: 100 }, () =>
	Array.from({ length: problem.weights.length }, () => Math.random() > 0.5)
);

const {population: newPopulation} = evolveSimple(population, {
	fitness,
	crossover: crossTwoPoint,
	mutation: mutFlipBit(0.05),
	selection: selTournament,
}, {
	ngen: 100
});