Pagerank Prediction Script ??

Hi

I have written pagerank prediction script but I cant get true values. Do you help me about this code ?

function futurepagerank ( $url ) {
    
    $outlink = 42;
    $den = 0.85;
    $domains = mysql_query("select b.* from exchange as a, sites as b where a.linkdomain = '".$url."' and b.domain = a.domain");
    $ug = 0;
    while ($d = mysql_fetch_array($domains)) {
        $ug+= $d[pagerank]/$outlink;
    }
    
    $d1 = $den*$ug;
    $d2 = 1-$den;
    $final = $d1+$d2;  
    return ($final);
} 

PHP:

Pagerank Formula
PRA = 1-d + d*( PRs1/Cs1 + PRs2/Cs2 + PRs3/Cs3 + ... + PRsn/Csn)

My script example output

1-dampfactor+dampfactor x ((Pr/outboundlink)+(Pr/outboundlink)+(Pr/outboundlink))

1-0.85+0.85 x ((3/42)+(3/42)+(4/42))