lucene-java-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Kasun Perera <>
Subject Calculating IDF value more efficiently
Date Sat, 28 Apr 2012 02:38:03 GMT
This is my program to calculate TF-IDF value for a document in a collection
of documents. This is working fine, but takes lot of time when calculating
the "IDF" values (finding the no of documents which contains particular

Is there a more efficient way of finding the no of documents which contains
a particular term?

freq = termsFreq.getTermFrequencies();

terms = termsFreq.getTerms();

int noOfTerms = terms.length;

score = new float[noOfTerms];
DefaultSimilarity simi = new DefaultSimilarity();

        for (i = 0; i < noOfTerms; i++) {

            int noofDocsContainTerm = noOfDocsContainTerm(terms[i]);

            float tf =[i]);

            float idf = simi.idf(noofDocsContainTerm, noOfDocs);

            score[i] = tf * idf ;



public int noOfDocsContainTerm(String querystr) throws
CorruptIndexException, IOException, ParseException{

QueryParser qp=new QueryParser(Version.LUCENE_35, "docuemnt", new

Query q=qp.parse(querystr);

int hitsPerPage = docNames.length; //minumum number or search results
IndexSearcher searcher = new IndexSearcher(ramMemDir, true);
TopScoreDocCollector collector = TopScoreDocCollector.create(hitsPerPage, true);, collector);

ScoreDoc[] hits = collector.topDocs().scoreDocs;

    return hits.length;


Kasun Perera

  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message