randomizer.js

README.md

randomizer.js

Random number generator, based on http://michalbe.blogspot.com/2011/02/javascript-random-numbers-with-custom.html

Features

• You can serialize the state of the Randomizer for later use.
• Keeps track of how many times .next was called on the original seed.
• Access to the constant, prime, seed, and maximum.

Usage

var gen = new Randomizer({ seed: 1337 });
gen.next().seed; // 10954078
gen.next().seed; // 89746761091
gen.next().seed; // 735295213618600
gen.next().seed; // 709183569150976
gen.next().seed; // 697462746006528

randomizer.js

function Randomizer(opts){
    opts = opts || {};
    if(!(this instanceof Randomizer)){
        return new Randomizer(opts);
    }
    this.__opts = opts;
    this.update(this.__opts);

    return this;
}

Randomizer.prototype.update = function(opts){
    this.seed = opts.seed || Date.now();
    this.constant = opts.constant || (Math.pow(2, 13) + 1);
    this.prime = opts.prime || 37;
    this.maximum = opts.maximum || Math.pow(2, 50);
    this.index = opts.index || 0;

    return this;
}

Randomizer.prototype.reset = function(opts){
    this.update(this.__opts);
    return this;
}

Randomizer.prototype.next = function(){
    this.seed *= this.constant;
    this.seed += this.prime;
    this.seed %= this.maximum;
    this.index += 1;

    return this;
}

Randomizer.prototype.serialize = function(){
    return {
        seed: this.seed,
        constant: this.constant,
        prime: this.prime,
        maximum: this.maximum,
        index: this.index
    }
}