File Content: DefaultSimilarity.php <?php /** * Zend Framework (http://framework.zend.com/) * * @link http://github.com/zendframework/zf2 for the canonical source repository * @copyright Copyright (c) 2005-2012 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd New BSD License * @package Zend_Search */ namespace ZendSearch\Lucene\Search\Similarity; use ZendSearch\Lucene\Search\Similarity\AbstractSimilarity; /** * @category Zend * @package Zend_Search_Lucene * @subpackage Search */ class DefaultSimilarity extends AbstractSimilarity { /** * Implemented as '1/sqrt(numTerms)'. * * @param string $fieldName * @param integer $numTerms * @return float */ public function lengthNorm($fieldName, $numTerms) { if ($numTerms == 0) { return 1E10; } return 1.0/sqrt($numTerms); } /** * Implemented as '1/sqrt(sumOfSquaredWeights)'. * * @param float $sumOfSquaredWeights * @return float */ public function queryNorm($sumOfSquaredWeights) { return 1.0/sqrt($sumOfSquaredWeights); } /** * Implemented as 'sqrt(freq)'. * * @param float $freq * @return float */ public function tf($freq) { return sqrt($freq); } /** * Implemented as '1/(distance + 1)'. * * @param integer $distance * @return float */ public function sloppyFreq($distance) { return 1.0/($distance + 1); } /** * Implemented as 'log(numDocs/(docFreq+1)) + 1'. * * @param integer $docFreq * @param integer $numDocs * @return float */ public function idfFreq($docFreq, $numDocs) { return log($numDocs/(float)($docFreq+1)) + 1.0; } /** * Implemented as 'overlap/maxOverlap'. * * @param integer $overlap * @param integer $maxOverlap * @return float */ public function coord($overlap, $maxOverlap) { return $overlap/(float)$maxOverlap; } } Submit