Examples of org.apache.lucene.search.similarities.LMDirichletSimilarity

Package org.apache.lucene.search.similarities

Examples of org.apache.lucene.search.similarities.LMDirichletSimilarity

org.apache.lucene.search.similarities.LMDirichletSimilarity
Bayesian smoothing using Dirichlet priors. From Chengxiang Zhai and John Lafferty. 2001. A study of smoothing methods for language models applied to Ad Hoc information retrieval. In Proceedings of the 24th annual international ACM SIGIR conference on Research and development in information retrieval (SIGIR '01). ACM, New York, NY, USA, 334-342.
The formula as defined the paper assigns a negative score to documents that contain the term, but with fewer occurrences than predicted by the collection language model. The Lucene implementation returns {@code 0} for suchdocuments.
@lucene.experimental

    // Can be null, in which case we don't check for credentials.
    this.credentials = credentials;


    IndexReader reader = DirectoryReader.open(FSDirectory.open(indexPath));
    searcher = new IndexSearcher(reader);
    searcher.setSimilarity(new LMDirichletSimilarity(2500.0f));
  }

View Full Code Here

    IndexSearcher searcher = new IndexSearcher(reader);


    if (similarity.equalsIgnoreCase("BM25")) {
      searcher.setSimilarity(new BM25Similarity());
    } else if (similarity.equalsIgnoreCase("LM")) {
      searcher.setSimilarity(new LMDirichletSimilarity(2500.0f));
    }


    QueryParser p = new QueryParser(Version.LUCENE_43, StatusField.TEXT.name,
        IndexStatuses.ANALYZER);

View Full Code Here

    IndexSearcher searcher = new IndexSearcher(reader);


    if (similarity.equalsIgnoreCase("BM25")) {
      searcher.setSimilarity(new BM25Similarity());
    } else if (similarity.equalsIgnoreCase("LM")) {
      searcher.setSimilarity(new LMDirichletSimilarity(2500.0f));
    }


    QueryParser p = new QueryParser(Version.LUCENE_43, IndexStatuses.StatusField.TEXT.name, IndexStatuses.ANALYZER);
    Query query = p.parse(queryText);
    Filter filter = NumericRangeFilter.newLongRange(StatusField.ID.name, 0L, maxId, true, true);

View Full Code Here


    @Inject
    public LMDirichletSimilarityProvider(@Assisted String name, @Assisted Settings settings) {
        super(name);
        float mu = settings.getAsFloat("mu", 2000f);
        this.similarity = new LMDirichletSimilarity(mu);
    }

View Full Code Here

TOP

Related Classes of org.apache.lucene.search.similarities.LMDirichletSimilarity

cc.twittertools.search.api.TrecSearchHandler

cc.twittertools.search.local.RunQueries

cc.twittertools.search.local.SearchStatuses

org.apache.lucene.search.Explanation

org.elasticsearch.index.similarity.LMDirichletSimilarityProvider

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.