If I set the boost=0 at query time and the query contains only terms with boost=0, the scores are NaN (because weight.queryNorm = 1/0 = infinity), instead of 0.
Peter On Sun, Mar 1, 2009 at 9:27 PM, Erick Erickson <erickerick...@gmail.com>wrote: > FWIW, Hossman pointed out that the difference between index and > query time boosts is that index time boosts on title, for instance, > express "I care about this document's title more than other documents' > titles [when it matches]" Query time boosts express "I care about matches > on the title field more than matches on other fields". > > Best > Erick > > On Sun, Mar 1, 2009 at 8:57 PM, Peter Keegan <peterlkee...@gmail.com> > wrote: > > > As suggested, I added a query-time boost of 0.0f to the 'literals' field > > (with index-time boost still there) and I did get the same scores for > both > > queries :) (there is a subtlety between index-time and query-time > boosting > > that I missed.) > > > > I also tried disabling the coord factor, but that had no affect on the > > score, when combined with the above. This seems ok in this example since > > the > > the matching terms had boost = 0. > > > > Thanks Yonik, > > Peter > > > > > > > > On Sat, Feb 28, 2009 at 6:02 PM, Yonik Seeley < > yo...@lucidimagination.com > > >wrote: > > > > > On Sat, Feb 28, 2009 at 3:02 PM, Peter Keegan <peterlkee...@gmail.com> > > > wrote: > > > >> in situations where you deal with simple query types, and matching > > > query > > > > structures, the queryNorm > > > >> *can* be used to make scores semi-comparable. > > > > > > > > Hmm. My example used matching query structures. The only difference > was > > a > > > > single term in a field with zero weight that didn't exist in the > > matching > > > > document. But one score was 3X the other. > > > > > > But the zero boost was an index-time boost, and the queryNorm takes > > > into account query-time boosts and idfs. You might get closer to what > > > you expect with a query time boost of 0.0f > > > > > > The other thing affecting the score is the coord factor - the fact > > > that fewer of the optional terms matched (1/2) lowers the score. The > > > coordination factor can be disabled on any BooleanQuery. > > > > > > If you do both of the above, I *think* you would get the same scores > > > for this specific example. > > > > > > -Yonik > > > http://www.lucidimagination.com > > > > > > --------------------------------------------------------------------- > > > To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org > > > For additional commands, e-mail: java-user-h...@lucene.apache.org > > > > > > > > >
