On Aug 8, 2005, at 1:19 PM, Rajesh Munavalli wrote:
2 How term weight is calculated in Lucene, how many types of term
weight calculating formulas are implemented and what are they?
TF-IDF weighting is used with some modifications to how the raw
score is
computed. You can refer to "Lucene In Action" by Otis Gospodnetic and
Erik Hatcher" page 78. Here is the formula
= SUMMATION {tf(t in d).idf(t).boost(t.field in d). lengthNorm
(t.field
in d)
t in q
Note that the most crucial errata for Lucene in Action is on that
very formula. The corrected one is here:
http://www.lucenebook.com/blog/errata/scoring_formula_omission.html
Erik
