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  Classes of Cesar D. Rodas  >  guaranix Rank  >  gRank.php  >  Download  
File: gRank.php
Role: Class source
Content type: text/plain
Description: This is the class that will calcualte the PR
Class: guaranix Rank
Implementation of the Google page rank algorithm
Author: By
Last change: One error were fix.

On my test I defined DUMPING, but in the current version, it was changed to $this->dump;

Now it works Well.
Date: 2006-10-13 12:13
Size: 4,663 bytes
 

Contents

Class file image Download
<?
/****************************************************************************************
*    guaranix Rank                                                                      *
*                                                                                       *
*    This is a class that implements the Google Rank algorithm called PageRank.         *
*    The algorithm is too much effective  for get what Page (or what are you trying     *
*    to rank) is more important than the others.                                        *
*                                                                                       *
*    The whole algorithm with explanation could be found at:                            *
*    http://dbpubs.stanford.edu:8090/pub/1999-66                                        *
*                                                                                       *
*    Becouse the algorithm is not mine (I didn't do the research about this ranking)    *
*    this source is free                                                                *
*                                                                                       *
*                                                                                       *
****************************************************************************************/

class gRank
{
    var $mysql;
    var $table;
    
    var $dump; 
    var $sql_limit;  #SQL limit 
    
    function gRank()
    {
        $this->dump = 0.85;
        $this->sql_limit = 1000;
    }
    function calculate()
    {
        print "Preparing... ";
        $this->Prepare();
        print "Prepared\n";
        
        print "Calculating the Pagerank with out Danglins\n";
        $this->CalculatePR_WitoutDanglings();
        
        print "Calculating the Pagerank\n";
        $this->CalculatePR();
        $this->FinishPR();
        print "Finish, all the result are in the table PR_FINISHED\n";
        
        
    }
    
    function FinishPR()
    {
        global $sql_finish;
        
        foreach($sql_finish as $Sql)
            mysql_query($Sql,$this->mysql) or die(mysql_error($this->mysql));
    }
    
    function Prepare() 
    {
        global $sql;
        
        foreach($sql as $Sql)
            mysql_query($Sql,$this->mysql) or die(mysql_error($this->mysql));
        
        #Now we will calculate formulates it of each page for its PageRank 
        for($i=0; ;$i++)
        {
            $main = mysql_query("select id from tmp_pr where formula = '' limit ".$this->sql_limit,$this->mysql) or die(mysql_error($this->mysql));
            if (mysql_num_rows($main) == 0) break;
            
            while ($row = mysql_fetch_array($main)) 
            {
                $Sql = "select pagerank.master, tmp_pr.nroout from pagerank inner 
                    join tmp_pr on (tmp_pr.id = pagerank.master) where pagerank.slave = ".$row['id'];
                
                $xSql = mysql_query($Sql, $this->mysql) or die(mysql_error( $this->mysql));
                $formula = "";
                
                while ($row1 = mysql_fetch_array($xSql))
                {
                    $formula .= "PR(".$row1['master'].")/".$row1['nroout']." + ";
                }
                $formula = substr($formula,0,strlen($formula) - 2); 
                $formula = mysql_escape_string($formula);
                mysql_free_result($xSql);
                $Sql = "update tmp_pr set formula = '".$formula."' where id = ".$row['id'];
                
                mysql_query($Sql,$this->mysql) or die(mysql_error($this->mysql));
            }
        }
    }
    
    function CalculatePR_WitoutDanglings()
    {
        for ($i=0; $i < 52; $i++)
        {
            print "\tItineracion $i\n";
            for ($e = 0; ; $e++)
            {
                if ($this->InternalPRcalculator($e,false) == false)
                    break;
            }
        }
    }
    
    function CalculatePR()
    {
        for ($e = 0; ; $e++)
        {
            if ($this->InternalPRcalculator($e) == false)
                break;
        }
    }
    
    function InternalPRcalculator($Start, $dangling = true)
    {
        global $buff;
        $start = $Start * $this->sql_limit;
        $where = "";
        if (!$dangling)
        {
            $where = "where nroout != 0"; 
        }
        
        $sql = mysql_query("select id, formula from tmp_pr $where limit $start, ".$this->sql_limit,$this->mysql) or die(mysql_error($this->mysql));

        if (mysql_num_rows($sql) == 0)
            return false;
        while ($row = mysql_fetch_array($sql))
        {
            eval('$nro = (float)'.$row['formula'].';');
            $nro = (float)(1 - $this->dump) + $this->dump * ($nro);
            mysql_query("update tmp_pr set pr = '$nro' where id = ".$row['id']);
            $buff[$row['id']] = $nro; 
        }
        return true; 
    }
}

/*
*    This function will calcula the PR of a given page.
*/
function PR($i)
{
    global $buff; #This is the memory buffer
        
    if (!isset($buff[$i]))
    {
        $sql1 = mysql_query("select pr from tmp_pr where id = $i");
        $row = mysql_fetch_array($sql1);
        mysql_free_result($sql1);
        $buff[$i] = $row[0];
    }
    return $buff[$i];
}


?>