這篇文章主要介紹了關于php實現PageRank的實例,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 $i++) { $example- caculate(); var_dump($example- rank);}
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