On 4/10/2009 1:08 PM, Jack Stahl wrote: > Perhaps you'd find it easier to implement the equivalent: > > log(s1(d, q))*a1 + ... + log(sN(d, q))*aN
Yes, that's fine too - that's actually what I'd be optimizing anyway. But how would I do that? If I took the query boost route, how do I get a TermQuery to produce a score in log-space, while keeping the boost in regular space? Or if I took the CustomScoreQuery route, how do I combine two Query scores (not a Query score and a ValueSourceQuery score)? Steve > > On Fri, Apr 10, 2009 at 12:56 PM, Steven Bethard <beth...@stanford.edu>wrote: > >> I need to have a scoring model of the form: >> >> s1(d, q)^a1 * s2(d, q)^a2 * ... * sN(d, q)^aN >> >> where "d" is a document, "q" is a query, "sK" is a scoring function, and >> "aK" is the exponential boost factor for that scoring function. As a >> simple example, I might have: >> >> s1 = TF-IDF score matching "text" field (e.g. a TermQuery) >> a1 = 1.0 >> >> s2 = TF-IDF score matching "author" field (e.g. a TermQuery) >> a2 = 0.1 >> >> s3 = PageRank score (e.g. a FieldScoreQuery) >> a3 = 0.5 >> >> It's important that the "aK" parameters are exponents in the scoring >> function and not just multipliers because it allows me to do a >> particular kind of optimized search for the best parameter values. >> >> How can I achieve this? My first thought was just that I should set the >> boost factor for each query, but the boost factor is just a multiplier, >> right? >> >> My second thought was to subclass CustomScoreQuery and override >> customScore, but as far as I can tell, CustomScoreQuery can only combine >> a Query with a ValueSourceQuery, while I need to combine a Query with >> another Query (e.g. the example above with two TermQuery scores). >> >> How should I go about this? >> >> Thanks in advance, >> >> Steve >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org >> For additional commands, e-mail: java-user-h...@lucene.apache.org >> >> > --------------------------------------------------------------------- To unsubscribe, e-mail: java-user-unsubscr...@lucene.apache.org For additional commands, e-mail: java-user-h...@lucene.apache.org
