Random number generating (Box-Muller)

gistfile1.js

var Random = {

  /**
   * Numbers between ~( -2 to 2 )
   * http://stackoverflow.com/questions/75677/converting-a-uniform-distribution-to-a-normal-distribution
   * http://c-faq.com/lib/gaussian.html
   */
  gaussian: function() {
    var x1, x2, r;

    do {
      x1 = 2 * Math.random() - 1;
      x2 = 2 * Math.random() - 1;
      r = x1 * x1 + x2 * x2;      
      // Check if generated number is range [0,1]
    } while (r >= 1 || r === 0);
    return Math.sqrt(-2 * Math.log(r) / r) * x1;
  },

  normalDist: function(mean, stdDev) {
    return mean + (this.gaussian() * stdDev);
  }
};
for (var i = -20; i <= 20; i += .25) 
  document.write(Random.normalDist(0, i) + '<br />');