Feel free to create a JIRA and put up a patch if you can. On Tue, Dec 29, 2015 at 4:26 PM, Alessandro Benedetti <abenede...@apache.org > wrote:
> Hi guys, > While I was exploring the way we build the More Like This query, I > discovered a part I am not convinced of : > > > > Let's see how we build the query : > org.apache.lucene.queries.mlt.MoreLikeThis#retrieveTerms(int) > > 1) we extract the terms from the interesting fields, adding them to a map : > > Map<String, Int> termFreqMap = new HashMap<>(); > > *( we lose the relation field-> term, we don't know anymore where the term > was coming ! )* > > org.apache.lucene.queries.mlt.MoreLikeThis#createQueue > > 2) we build the queue that will contain the query terms, at this point we > connect again there terms to some field, but : > > ... >> // go through all the fields and find the largest document frequency >> String topField = fieldNames[0]; >> int docFreq = 0; >> for (String fieldName : fieldNames) { >> int freq = ir.docFreq(new Term(fieldName, word)); >> topField = (freq > docFreq) ? fieldName : topField; >> docFreq = (freq > docFreq) ? freq : docFreq; >> } >> ... > > > We identify the topField as the field with the highest document frequency > for the term t . > Then we build the termQuery : > > queue.add(new ScoreTerm(word, *topField*, score, idf, docFreq, tf)); > > In this way we lose a lot of precision. > Not sure why we do that. > I would prefer to keep the relation between terms and fields. > The MLT query can improve a lot the quality. > If i run the MLT on 2 fields : *description* and *facilities* for example. > It is likely I want to find documents with similar terms in the > description and similar terms in the facilities, without mixing up the > things and loosing the semantic of the terms. > > Let me know your opinion, > > Cheers > > > -- > -------------------------- > > Benedetti Alessandro > Visiting card : http://about.me/alessandro_benedetti > > "Tyger, tyger burning bright > In the forests of the night, > What immortal hand or eye > Could frame thy fearful symmetry?" > > William Blake - Songs of Experience -1794 England > -- Anshum Gupta