Cakephp : 類似度関数(similar_text関数利用)

PHPの関数 : similar_text関数を用いて、２つのテキストの類似度を算出しました。
今回は課題テーブルsubjectsのviewで類似度を算出し、similaritiesテーブルに格納しました。

        public function view($id = null) {
                if (!$this->Subject->exists($id)) {
                        throw new NotFoundException(__('Invalid subject'));
                }
                $options = array('conditions' => array('Subject.' . $this->Subject->primaryKey => $id));
                $this->set('subject', $this->Subject->find('first', $options));

                $subject = $this->Subject->find('first', $options);

                App::import('Model', 'Similarity');
                $this->Similarity = new Similarity;

                for($i = 0; $i < count($subject['Report']) - 1 ; $i++){
                        for($j = $i + 1; $j < count($subject['Report']);$j++){

                                similar_text($subject['Report'][$i]['answer'], $subject['Report'][$j]['answer'], $diff);
                                $data = array('Similarity' =>
                                                array('fromid' => $subject['Report'][$i]['id'],
                                                        'toid' => $subject['Report'][$j]['id'],
                                                        'value' => $diff
                                                )
                                        );
                                $this->Similarity->create();
                                $fields = array('fromid', 'toid', 'value');
                                $this->Similarity->save($data, false, $fields);
                        }

                }
        }

参考
http://php.net/manual/ja/function.similar-text.php
http://nitou.dip.jp/blog/archives/4238