[LUCENE-1993] MoreLikeThis - allow to exclude terms that appear in too many documents (patch included)

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.9
• Fix Version/s: 3.0
• Component/s: modules/other
• Lucene Fields: New, Patch Available
• Assignee: Michael McCandless
• Reporter: Christian Steinert
• Created: 19/Oct/09 11:48
• Updated: 28/Aug/22 12:11
• Resolved: 20/Oct/09 12:00

Description

The MoreLikeThis class allows to generate a likeness query based on a given document. So far, it is impossible to suppress words from the likeness query, that appear in almost all documents, making it necessary to use extensive lists of stop words.

Therefore I suggest to allow excluding words for which a certain absolute document count or a certain percentage of documents is exceeded. Depending on the corpus of text, words that appear in more than 50 or even 70% of documents can usually be considered insignificant for classifying a document.