See http://wiki.apache.org/solr/SolrRelevancyFAQ#How_can_I_boost_the_score_of_newer_documents for more info on how to do a multiplicative boost.
-Yonik http://www.lucidimagination.com On Tue, Jun 22, 2010 at 11:13 PM, Li Li <fancye...@gmail.com> wrote: > I want to integrate document's timestamp into scoring of search. And I > find an example in the book "Solr 1.4 Enterprise Search Server" about > function query. I want to boost a document which is newer. so it may > be a function such as 1/(timestamp+1) . But the function query is > added to the final result, not multiplied. So I can't adjust the > parameter well. > e.g > search term is term1, topdocs are doc1 with score 2.0; doc2 with score 1.5. > search term is term2, topdocs are doc1 with score 20; doc2 with score 15. > it is hard to adjust the relative score of these 2 docs with add a value. i > if it is multiply, it's easy. if doc1 is very old, we assign a score > 1,and doc2 is new, we assign a score 2 > thus total score is 2.0*1 1.5*2 . So doc2 rank higher than doc1 > but when use add, 2.0 + weight*1, 1.5 +weight*2, it's hard to get a > proper weight. > if we let weight is 1, it works well for term1 > but with term2, it 20 +1*1.5 15+1*2 time has little influence on the > final result. >
