Thanks everyone. I updated the wiki. If you have a chance please take a look and check to make sure I got it right on the wiki.
http://wiki.apache.org/solr/DisMaxQParserPlugin#tie_.28Tie_breaker.29 Tom -----Original Message----- From: Chris Hostetter [mailto:hossman_luc...@fucit.org] Sent: Thursday, April 14, 2011 5:41 PM To: solr-user@lucene.apache.org; yo...@lucidimagination.com Cc: Burton-West, Tom Subject: Re: Understanding the DisMax tie parameter : Perhaps the parameter could have had a better name. It's essentially : max(score of matching clauses) + tie * (score of matching clauses that : are not the max) : : So it can be used and thought of as a tiebreak only in the sense that : if two docs match a clause (with essentially the same score), then a : small tie value will act as a tiebreaker *if* one of those docs also : matches some other fields. correct. w/o a tiebreaker value, a dismax query will only look at the maximum scoring clause for each doc -- the "tie" param is named for it's ability to help break ties when multiple documents have the same score from the max scoring clause -- by adding in a small portion of the scores (based on the 0->1 ratio of the "tie" param) from the other clauses. -Hoss
