[Sommaire] [Imprimer]

   1  <?php
   2  /**
   3   * Zend Framework
   4   *
   5   * LICENSE
   6   *
   7   * This source file is subject to version 1.0 of the Zend Framework
   8   * license, that is bundled with this package in the file LICENSE, and
   9   * is available through the world-wide-web at the following URL:
  10   * http://www.zend.com/license/framework/1_0.txt. If you did not receive
  11   * a copy of the Zend Framework license and are unable to obtain it
  12   * through the world-wide-web, please send a note to license@zend.com
  13   * so we can mail you a copy immediately.
  14   *
  15   * @package    Zend_Search_Lucene
  16   * @subpackage Search
  17   * @copyright  Copyright (c) 2005-2006 Zend Technologies USA Inc. (http://www.zend.com)
  18   * @license    http://www.zend.com/license/framework/1_0.txt Zend Framework License version 1.0
  19   */
  20  
  21  
  22  /**
  23   * @package    Zend_Search_Lucene
  24   * @subpackage Search
  25   * @copyright  Copyright (c) 2005-2006 Zend Technologies USA Inc. (http://www.zend.com)
  26   * @license    http://www.zend.com/license/framework/1_0.txt Zend Framework License version 1.0
  27   */
  28  class Zend_Search_Lucene_Search_Similarity_Default extends Zend_Search_Lucene_Search_Similarity
  29  {
  30  
  31      /**
  32       * Implemented as '1/sqrt(numTerms)'.
  33       *
  34       * @param string $fieldName
  35       * @param integer numTerms
  36       * @return float
  37       */
  38      public function lengthNorm($fieldName, $numTerms)
  39      {
  40          return 1.0/sqrt($numTerms);
  41      }
  42  
  43      /**
  44       * Implemented as '1/sqrt(sumOfSquaredWeights)'.
  45       *
  46       * @param float $sumOfSquaredWeights
  47       * @return float
  48       */
  49      public function queryNorm($sumOfSquaredWeights)
  50      {
  51          return 1.0/sqrt($sumOfSquaredWeights);
  52      }
  53  
  54      /**
  55       * Implemented as 'sqrt(freq)'.
  56       *
  57       * @param float $freq
  58       * @return float
  59       */
  60      public function tf($freq)
  61      {
  62          return sqrt($freq);
  63      }
  64  
  65      /**
  66       * Implemented as '1/(distance + 1)'.
  67       *
  68       * @param integer $distance
  69       * @return float
  70       */
  71      public function sloppyFreq($distance)
  72      {
  73          return 1.0/($distance + 1);
  74      }
  75  
  76      /**
  77       * Implemented as 'log(numDocs/(docFreq+1)) + 1'.
  78       *
  79       * @param integer $docFreq
  80       * @param integer $numDocs
  81       * @return float
  82       */
  83      public function idfFreq($docFreq, $numDocs)
  84      {
  85          return log($numDocs/(float)($docFreq+1)) + 1.0;
  86      }
  87  
  88      /**
  89       * Implemented as 'overlap/maxOverlap'.
  90       *
  91       * @param integer $overlap
  92       * @param integer $maxOverlap
  93       * @return float
  94       */
  95      public function coord($overlap, $maxOverlap)
  96      {
  97          return $overlap/(float)$maxOverlap;
  98      }
  99  }