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