goller 2004/10/13 11:42:20 Modified: src/java/org/apache/lucene/search Similarity.java Log: Improved Javadoc: Formula for score computation corrected. Revision Changes Path 1.16 +27 -4 jakarta-lucene/src/java/org/apache/lucene/search/Similarity.java Index: Similarity.java =================================================================== RCS file: /home/cvs/jakarta-lucene/src/java/org/apache/lucene/search/Similarity.java,v retrieving revision 1.15 retrieving revision 1.16 diff -u -r1.15 -r1.16 --- Similarity.java 10 Oct 2004 18:43:18 -0000 1.15 +++ Similarity.java 13 Oct 2004 18:42:20 -0000 1.16 @@ -40,14 +40,15 @@ * <td valign="middle" align="center"> * <big><big><big><big><big>Σ</big></big></big></big></big></td> * <td valign="middle"><small> - * [EMAIL PROTECTED] #tf(int) tf}(t in d) * - * [EMAIL PROTECTED] #idf(Term,Searcher) idf}(t) * + * ( [EMAIL PROTECTED] #tf(int) tf}(t in d) * + * [EMAIL PROTECTED] #idf(Term,Searcher) idf}(t)^2 * + * [EMAIL PROTECTED] Query#getBoost getBoost}(t in q) * * [EMAIL PROTECTED] Field#getBoost getBoost}(t.field in d) * - * [EMAIL PROTECTED] #lengthNorm(String,int) lengthNorm}(t.field in d) + * [EMAIL PROTECTED] #lengthNorm(String,int) lengthNorm}(t.field in d) ) * </small></td> * <td valign="middle" rowspan="2"> * * [EMAIL PROTECTED] #coord(int,int) coord}(q,d) * - * [EMAIL PROTECTED] #queryNorm(float) queryNorm}(q) + * [EMAIL PROTECTED] #queryNorm(float) queryNorm}(sumOfSqaredWeights) * </td> * </tr> * <tr> @@ -56,6 +57,28 @@ * </td> * </tr> * </table> + * + * <p> where + * + * <table cellpadding="0" cellspacing="0" border="0"> + * <tr> + * <td valign="middle" align="right" rowspan="2">sumOfSqaredWeights =<br></td> + * <td valign="middle" align="center"> + * <big><big><big><big><big>Σ</big></big></big></big></big></td> + * <td valign="middle"><small> + * ( [EMAIL PROTECTED] #idf(Term,Searcher) idf}(t) * + * [EMAIL PROTECTED] Query#getBoost getBoost}(t in q) )^2 + * </small></td> + * </tr> + * <tr> + * <td valign="top" align="right"> + * <small>t in q</small> + * </td> + * </tr> + * </table> + * + * <p> Note that the above formula is motivated by the cosine-distance or dot-product + * between document and query vector, which is implemented by [EMAIL PROTECTED] DefaultSimilarity}. * * @see #setDefault(Similarity) * @see IndexWriter#setSimilarity(Similarity)
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