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copied!<p>if you don't need the seeding capability, just use <code>Math.random()</code> and build helper functions around it (eg. <code>randRange(start, end)</code>).</p> <p>I'm not sure what RNG you're using, but it's best to know and document it so you're aware of it's characteristics and limitations.</p> <p>Like Starkii said, Mersenne Twister is a good PRNG, but it isn't easy to implement. If you want to do it yourself try implementing a <a href="http://en.wikipedia.org/wiki/Linear_congruential_generator" rel="nofollow noreferrer">LCG</a> - it's very easy, has decent randomness qualities (not as good as Mersenne Twister), and you can use some of the popular constants.</p> <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false"> <div class="snippet-code"> <pre class="snippet-code-js lang-js prettyprint-override"><code>function RNG(seed) { // LCG using GCC's constants this.m = 0x80000000; // 2**31; this.a = 1103515245; this.c = 12345; this.state = seed ? seed : Math.floor(Math.random() * (this.m - 1)); } RNG.prototype.nextInt = function() { this.state = (this.a * this.state + this.c) % this.m; return this.state; } RNG.prototype.nextFloat = function() { // returns in range [0,1] return this.nextInt() / (this.m - 1); } RNG.prototype.nextRange = function(start, end) { // returns in range [start, end): including start, excluding end // can't modulu nextInt because of weak randomness in lower bits var rangeSize = end - start; var randomUnder1 = this.nextInt() / this.m; return start + Math.floor(randomUnder1 * rangeSize); } RNG.prototype.choice = function(array) { return array[this.nextRange(0, array.length)]; } var rng = new RNG(20); for (var i = 0; i < 10; i++) console.log(rng.nextRange(10, 50)); var digits = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']; for (var i = 0; i < 10; i++) console.log(rng.choice(digits));</code></pre> </div> </div> </p>

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