[LUCENE-3220] Implement various ranking models as Similarities

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: flexscoring branch
• Fix Version/s: flexscoring branch
• Component/s: core/query/scoring, core/search
• Labels: gsoc gsoc2011
• Lucene Fields: New
• Assignee: David Mark Nemeskey
• Reporter: David Mark Nemeskey
• Due: 04/Jul/11
• Created: 20/Jun/11 10:48
• Updated: 28/Aug/22 12:50
• Resolved: 12/Aug/11 13:22

Description

With LUCENE-3174 done, we can finally work on implementing the standard ranking models. Currently DFR, BM25 and LM are on the menu.

Done:

• EasyStats: contains all statistics that might be relevant for a ranking algorithm
• EasySimilarity: the ancestor of all the other similarities. Hides the DocScorers and as much implementation detail as possible
• BM25: the current "mock" implementation might be OK
• LM
• DFR
• The so-called Information-Based Models

Issue Links

• is depended upon by: LUCENE-3357 Unit and integration test cases for the new Similarities