Reitingo apskaiciavimo formule/funkcija (PHP)

Gal kas turit pasirases funkcija ar bent formule pasidalinsit kaip apskaiciuot reitinga? :) Narsau google, bet ten meta basic tokius sprendimu budus. Imti average ir panasiai. Bet man reik, kad reitingas atspindetu reitinga atsizvelgiant i balsavusiu skaiciu.

Pvz.: Uz kazka prabalsuoja 125 zmones ir vidutinis reitingas buna 4.5. Kazkas prabalsuoja uz kita daikta 5 balais ir iskart sitas soka i virsu, nes turi didesni bala.

Gal kas minciu? :)

Taip. Facemash atsimeni? Ten labai nebloga reitingavimo sistema. http://en.wikipedia.org/wiki/Elo_rating_system#Mathematical_details

Iš įdomumo pabandžiau panaudoti šiek tiek modifikuotą Bayes'o teoremą. Kažkas gavosi, bet labai netestavau:

$users = array();

$user = new stdClass();
$user->votes = array(5,5,5,5,5,5,4,3,3,3,3);
$users[1] = $user;

$user = new stdClass();
$user->votes = array(5,5,5,5);
$users[2] = $user;

$user = new stdClass();
$user->votes = array(5,5,5,5,5,1,1,1,3,3,3);
$users[3] = $user;

$user = new stdClass();
$user->votes = array(5,5,5,5,3,3,3,3,3,3,3,1,1,1);
$users[4] = $user;



$all_ratings_count = 0;
$all_ratings_averages = 0;

foreach ($users as $user)
{
$all_ratings_count += count($user->votes);
$all_ratings_averages += array_sum($user->votes) / count($user->votes);
}


foreach ($users as $user)
{
$user->ba = ((($all_ratings_count / count($users)) * ($all_ratings_averages / count($users))) + array_sum($user->votes) * 1.5) / (count($user->votes) + (($all_ratings_count / count($users))));
$user->count = count($user->votes);
$user->avg = array_sum($user->votes) / count($user->votes);

       // Ismetu balsus del formatavimo
unset($user->votes);
}

echo "<pre>"; var_dump($users); echo "</pre>";

Rezultatas (perskaičiuotas reitingas "ba" kintamajam):

array(4) {
 [1]=>
 object(stdClass)#1 (3) {
   ["ba"]=>
   float(5.1533704390847)
   ["count"]=>
   int(11)
   ["avg"]=>
   float(4.1818181818182)
 }
 [2]=>
 object(stdClass)#2 (3) {
   ["ba"]=>
   float(4.9443413729128)
   ["count"]=>
   int(4)
   ["avg"]=>
   int(5)
 }
 [3]=>
 object(stdClass)#3 (3) {
   ["ba"]=>
   float(4.5105132962276)
   ["count"]=>
   int(11)
   ["avg"]=>
   float(3.3636363636364)
 }
 [4]=>
 object(stdClass)#4 (3) {
   ["ba"]=>
   float(4.3841991341991)
   ["count"]=>
   int(14)
   ["avg"]=>
   float(3.1428571428571)
 }
}