I am cross-posting this question here on behalf of a co-worker. The
original question is on StackOverflow at
http://stackoverflow.com/questions/1645197/boosting-multi-value-fields, but
I thought there is a better chance that someone on this list has come across
something similar than the more-general StackOverflow crowd. Any suggestions
would be greatly appreciated.
---------------------
I have a set of documents containing scored items that I'd like to index.
Our data structure looks like:
Document
ID
Text
List<RelatedScore>
RelatedScore
ID
Score
My first thought was to add each RelatedScore as a multi-value field using
the Boost property of the Field to modify the value of the particular score
when searching.
foreach (var relatedScore in document.RelatedScores) {
var field = new Field("RelatedScore", relatedScore.ID,
Field.Store.YES, Field.Index.UN_TOKENIZED);
field.SetBoost(relatedScore.Score);
luceneDoc.Add(field);
}
However, it appears that the "Norm" that is calculated applies to the entire
multi-field - all the RelatedScore" values for a document will end up having
the same score.
Is there a mechanism in Lucene to allow for this functionality? I would
rather not create another index just to account for this - it feels like
there should be a way using a single index. If there isn't a means to
accomplish this, a few ideas that we have to compensate are :
1. Insert the multi-value field items in order of descending value. Then
somehow add a positional-aware analysis to assign higher boost/score to the
first items in the field.
2. Add a high value score multiple times to the field. So, a RelatedScore
with Score==1 might be added three times, while a RelatedScore with
Score==.3 would only be added once.
Both of these will result in a loss of search fidelity on these fields, yes,
but they may be good enough. Any thoughts on this?
