Write a PHP function to get random float numbers

<?php
function rand_float($st_num=0,$end_num=1,$mul=1000000)
{
if ($st_num>$end_num) return false;
return mt_rand($st_num*$mul,$end_num*$mul)/$mul;
}
echo rand_float()."\n";
echo rand_float(0.6)."\n";
echo rand_float(0.5,0.6)."\n";
echo rand_float(0,20)."\n";
echo rand_float(0,3,2)."\n"; 
echo rand_float(0,2,20)."\n";
?>

Sample Output:

0.613314                                                    
0.886207                                                    
0.57955                                                     
17.570268                                                   
1.5                                                         
1.6