Apache lucene inverted index

Question

Does Lucene index use tf-idf as weights? Is it possible to define your own statistics and weights for each document, and "plug" them into Lucene?

femtoRgon femtoRgon · Accepted Answer · 2013-07-10T07:25:21

Yes, the default scoring algorithm incorporates tf-idf, and is fully documented in the TFIDFSiilarity documentation.

There are a number of ways to customize the scoring of documents.

The simplest and most common is to incorporate a boost, either on a field at index time, or on a query term when querying.
Many query types modify the scoring used for that query. Examples include ConstantScoreQuery and DisjunctionMaxQuery.
The Similarity you use defines the scoring algorithm. You could select a different one (ex. BM25Similarity).
You can implement your own Similarity, Usually by extending a higher-level implementation such as DefaultSimilarity, TFIDFSimilarity, or SimilarityBase