php實現PageRank的執行個體

這篇文章主要介紹了關於php實現PageRank的執行個體，有著一定的參考價值，現在分享給大家，有需要的朋友可以參考一下

php簡單實現PageRank演算法

<?phpheader("Content-type:text/html; charset=utf-8");class PageRank{    public $map = [];        public $rank = [];        public $inputList = []; // example web 'a' (has input link): web 'b'    public $size;        public $keyValue = 0.85;        public function __construct(array $map) {        $this->map = $map;                $this->size = count($this->map);    }    //init rank score and transform 'map' format to 'inputList' format    public function init()    {        $size = $this->size;                foreach ($this->map as $key => $value) {                    $this->inputList[$key] = [];        }        foreach ($this->map as $key => $value) {                    $this->rank[$key] = 1/$size;                    foreach ($value as $v) {                        if (empty($this->inputList[$v])) {                            $this->inputList[$v][] = $key;                } else {                    array_push($this->inputList[$v], $key);                }            }        }    }    public function caculate()    {        $tmp = $this->rank;                $keyValue = $this->keyValue;                $size = $this->size;                foreach ($this->inputList as $key => $value) {                    $score = (1 - $keyValue)/$size;                    foreach ($value as $v) {                        $cc = count($this->map[$v]);                        if ($cc) {                            $score += ($keyValue*(1/$cc * $this->rank[$v]));                }            }            $tmp[$key] = $score;        }        $this->rank = $tmp;    }}$map = [        'a' => ['b', 'c', 'd'],// web 'a' (has out link): web 'b', web 'c', web 'd'        'b' => ['a', 'd'],        'c' => ['b'],        'd' => ['b', 'c'],];$example = new PageRank($map);$example->init();echo '<pre>';for ($i = 0; $i < 10; $i++) {    $example->caculate();    var_dump($example->rank);}

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