Fatal error: Allowed memory size of 25165824 bytes exhausted (tried to allocate 35 bytes)

I am using Dijkstra algorithm in PHP. But I got this error

Fatal error: Allowed memory size of 25165824 bytes exhausted (tried to allocate 35 bytes) in C:\AppServ\www\direction\dijkstra.php on line 100

how can I optimize this algorithm to reduce memory consumption

<?php 
ini_set('memory_limit', '1M'); //Raise to 512 MB
ini_set('max_execution_time', '60'); //Raise to 512 MB
class Dijkstra { 

    var $visited = array(); 
    var $distance = array(); 
    var $previousNode = array(); 
    var $startnode =null; 
    var $map = array(); 
    var $infiniteDistance = 0; 
    var $numberOfNodes = 0; 
    var $bestPath = 0; 
    var $matrixWidth = 0; 

    function Dijkstra(&$ourMap, $infiniteDistance) { 
        $this -> infiniteDistance = $infiniteDistance; 
        $this -> map = &$ourMap; 
        $this -> numberOfNodes = count($ourMap); 
        $this -> bestPath = 0; 
    } 

    function findShortestPath($start,$to) { 
        $this -> startnode = $start; 
        for ($i=0;$i<$this -> numberOfNodes;$i++) { 
            if ($i == $this -> startnode) { 
                $this -> visited[$i] = true; 
                $this -> distance[$i] = 0; 
            } else { 
                $this -> visited[$i] = false; 
                $this -> distance[$i] = isset($this -> map[$this -> startnode][$i]) 
                    ? $this -> map[$this -> startnode][$i] 
                    : $this -> infiniteDistance; 
            } 
            $this -> previousNode[$i] = $this -> startnode; 
        } 

        $maxTries = $this -> numberOfNodes; 
        $tries = 0; 
        while (in_array(false,$this -> visited,true) && $tries <= $maxTries) {             
            $this -> bestPath = $this->findBestPath($this->distance,array_keys($this -> visited,false,true)); 
            if($to !== null && $this -> bestPath === $to) { 
                break; 
            } 
            $this -> updateDistanceAndPrevious($this -> bestPath);             
            $this -> visited[$this -> bestPath] = true; 
            $tries++; 
        } 
    } 

    function findBestPath($ourDistance, $ourNodesLeft) { 
        $bestPath = $this -> infiniteDistance; 
        $bestNode = 0; 
        for ($i = 0,$m=count($ourNodesLeft); $i < $m; $i++) { 
            if($ourDistance[$ourNodesLeft[$i]] < $bestPath) { 
                $bestPath = $ourDistance[$ourNodesLeft[$i]]; 
                $bestNode = $ourNodesLeft[$i]; 
            } 
        } 
        return $bestNode; 
    } 

    function updateDistanceAndPrevious($obp) {         
        for ($i=0;$i<$this -> numberOfNodes;$i++) { 
            if(     (isset($this->map[$obp][$i])) 
                &&    (!($this->map[$obp][$i] == $this->infiniteDistance) || ($this->map[$obp][$i] == 0 ))     
              开发者_JAVA百科  &&    (($this->distance[$obp] + $this->map[$obp][$i]) < $this -> distance[$i]) 
            )      
            { 
                    $this -> distance[$i] = $this -> distance[$obp] + $this -> map[$obp][$i]; 
                    $this -> previousNode[$i] = $obp; 
            } 
        } 
    } 

    function printMap(&$map) { 
        $placeholder = ' %' . strlen($this -> infiniteDistance) .'d'; 
        $foo = ''; 
        for($i=0,$im=count($map);$i<$im;$i++) { 
            for ($k=0,$m=$im;$k<$m;$k++) { 
                $foo.= sprintf($placeholder, isset($map[$i][$k]) ? $map[$i][$k] : $this -> infiniteDistance); 
            } 
            $foo.= "\n"; 
        } 
        return $foo; 
    } 

    function getResults($to) { 
    if(trim($to)!="")
    {
        $ourShortestPath = array(); 
        $foo = ''; 
        for ($i = 0; $i < $this -> numberOfNodes; $i++) { 
            if($to !== null && $to !== $i) { 
                continue; 
            } 
            $ourShortestPath[$i] = array(); 
            $endNode = null; 
            $currNode = $i; 
            $ourShortestPath[$i][] = $i; 
            while ($endNode === null || $endNode != $this -> startnode) { 
                $ourShortestPath[$i][] = $this -> previousNode[$currNode]; 
                $endNode = $this -> previousNode[$currNode]; 
                $currNode = $this -> previousNode[$currNode]; 
            } 
            $ourShortestPath[$i] = array_reverse($ourShortestPath[$i]); 
            if ($to === null || $to === $i) { 
            if($this -> distance[$i] >= $this -> infiniteDistance) { 
                $foo .= sprintf("no route from %d to %d. \n",$this -> startnode,$i); 
            } else { 
                $foo .= sprintf(' - Distance  = %d (km) <br> - Walking time ~ %d (hrs)<br> - Running time ~ %d (hrs)<br> - Driving time ~ %d (hrs)<br> Nodes [%d] : %s'."\n" , 
                        $this -> distance[$i], round($this -> distance[$i]/5,2),$this -> distance[$i]/17.2,$this -> distance[$i]/50, 
                        count($ourShortestPath[$i]), 
                        implode('-',$ourShortestPath[$i])); 
            } 
                if ($to === $i) { 
                    break; 
                } 
            } 
        } 
        }
        else $foo="";
        return $foo; 
    } 
} // end class 
?>

The script used all the memory it had the right to consume. Try raising the memory limit in php.ini or in code like this:

ini_set('memory_limit', '512M'); //Raise to 512 MB

It seems as you really run out of memory, this is exactly 24mb of memory. You can modify the maximum memory amount for PHP by modifying memory_limit in php.ini.

Can you show your algorithm?