public function testDistribution()
{
$twister = new MersenneTwister();
$twister->seed(424242);
$bins = array_fill(0, 2, 0);
for ($i = 0; $i < 1000; $i++) {
$number = $twister->extractNumber();
$bin = (int) floor($number / pow(2, 31));
$bins[$bin]++;
}
foreach ($bins as $count) {
$this->assertGreaterThan(400, $count);
}
}
/**
* Shuffle with seed
* @param array $arr
* @param $seed
* @return array
*/
function shuffle($arr, $seed = -1)
{
if ($seed == -1) {
return $arr;
}
$mt = new MersenneTwister($seed);
$new = $arr;
for ($i = count($new) - 1; $i > 0; $i--) {
$j = $mt->getNext(0, $i);
$tmp = $new[$i];
$new[$i] = $new[$j];
$new[$j] = $tmp;
}
return $new;
}