mt_srand

<?php

$val = mt_rand();

mt_srand($val);
$arr1 = array();

for($i = 0; $i < 1000; ++$i) {
    $arr1[] = mt_rand();
}

mt_srand($val);
$arr2 = array();

for($i = 0; $i < 1000; ++$i) {
    $arr2[] = mt_rand();
}

if($arr1 == $arr2) {
    echo 'true';
}
else {
    echo 'false';
}