Solr/Lucene Scorer

Scorer are parts of lucene Queries via the ‘weight’ query method. In short, the framework calls Query.weight(..).scorer(..) . Have a look at To use your own Query class in Solr, you’ll need to implement your own solr QueryParserPlugin that uses your own QParser that generates your previously implemented lucene Query. You then … Read more

Remove results below a certain score threshold in Solr/Lucene?

You could write your own Collector that would ignore collecting those documents that the scorer places below your threshold. Below is a simple example of this using Lucene.Net and C#. You’ll need to modify the example if you want to keep the calculated score. using System; using System.Collections.Generic; using Lucene.Net.Index; using Lucene.Net.Search; public class … Read more

Update specific field on SOLR index

Solr does not support updating individual fields yet, but there is a JIRA issue about this (almost 3 years old as of this writing). Until this is implemented, you have to update the whole document. UPDATE: as of Solr 4+ this is implemented, here’s the documentation.

get cosine similarity between two documents in lucene

As Julia points out Sujit Pal’s example is very useful but the Lucene 4 API has substantial changes. Here is a version rewritten for Lucene 4. import; import java.util.*; import org.apache.commons.math3.linear.*; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.core.SimpleAnalyzer; import org.apache.lucene.document.*; import org.apache.lucene.document.Field.Store; import org.apache.lucene.index.*; import*; import org.apache.lucene.util.*; public class CosineDocumentSimilarity { public static final String CONTENT … Read more

Hibernate Search | ngram analyzer with minGramSize 1

Updated answer for Hibernate Search 6 With Hibernate Search 6, you can define a second analyzer, identical to your “ngram” analyzer except that it does not have an ngram filter, and assign it as the searchAnalyzer for your field: public class Hospital { // … @FullTextField(analyzer = “ngram”, searchAnalyzer = “my_analyzer_without_ngrams”) private String name = … Read more