Apache Solr Search Patterns

Options to TF-IDF similarity

In addition to the default TF-IDF similarity implementation, other similarity implementations are available by default with Lucene and Solr. These models also work around the frequency of the searched term and the documents containing the searched term. However, the concept and the algorithm used to calculate the score differ.

Let us go through some of the most used ranking algorithms.

BM25 similarity

The Best Matching (BM25) algorithm is a probabilistic Information Retrieval (IR) model, while TF-IDF is a vector space model for information retrieval. The probabilistic IR model operates such that, given some relevant and non-relevant documents, we can calculate the probability of a term appearing in a relevant document, ...