GA.js

Genetic Algorithm with tournament selection and elite (the best solution always go further).

Example

Example

Read test.js and index.html.

Usage

Include underscore.js and ga.js in the header of the html file.

Create a new instance of Genetic. Pass as argument an object with the fitness function and the stop criteria as properties:

var ga = new Genetic({
    size: 100,
    steps: 1000,
    fitness:  function(c){
        return Math.sqrt(c.x*c.x+c.y*c.y);
    },
    criteria: function (){
        //bestFitness will give the fitness of the best, at any moment
        return this.bestFitness()<0.001;
    }
});

Add the features. The constructor must be called with functions to generate (random) and mutate features, and also the feature name:

ga.add(new Feature({
    name: 'x',
    random: function(){
        return Math.random();
    },
    mutate: function (x){
        return x * (1 + 0.1 * (0.5-Math.random()));
    }
}));

ga.add(new Feature({
    name: 'y',
    random: function(){
        return Math.random();
    },
    mutate: function (x){
        return x * (1 + 0.1 * (0.5-Math.random()));
    }
}));

Then:

ga.createPopulation();
ga.solve();

Access status:

var status = ga.status();
var result = ga.bestResult();

Results are satisfactory? If not, call solve again to iterate over more steps:

ga.solve();

To reset the GA, and create new population, pass some or none of the same arguments used in the constructor:

ga.reset({
    size: 100
});