detailed help on your class :: RSA?

Hi,

is it possible to get help on your php class in detailed explanation?I have some questions:

I need to know mostly these:
1) why do you set in private function

$u1 = '1'; // why ?
$u2 = '0'; // ? why?
$u3 = $Em; // why
$v1 = '0'; // why
$v2 = '1'; //why
$v3 = $Ee; // why

2) what's the point to do it that way?
3) why do you set $e to be 3 in the private function findE($m)?
4) $code = '0'; in public function encrypt ?
If it is possible i want to learn why do you made all of these in that way and why not in any other way. Thanks in advance.