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From Paul Libbrecht <p...@activemath.org>
Subject Re: best way to interest two queries?
Date Sat, 15 May 2010 21:17:51 GMT

Le 12-mai-10 à 10:55, mark harwood a écrit :

>
>
>>> two terminology questions:
>
>>> - is multiplier in the mail mentioned there the same as boost?
>
> This factor controls how many decimal places precision is retained  
> in the adjusted scores. Pick to low a multiplier and scores that are  
> only differentiated by a very small value will appear equal. Pick  
> too high a multiplier and you start to lose the most significant  
> parts of the score. This trade-off is summarised here for various  
> settings of "multiplier":

sorry, had overseen. Yes, that seems realistic to me.

> - I intended to use prefix and fuzzyqueries. I believe this is  
> contradictory to this or?
>
> You can wrap any queries with this class - the only limitation is it  
> hides all match info in a single byte encoded into the score which  
> only allows for 8 bits or 8 match flags i.e. reports on max 8  
> clauses. You could try use > 8 bits encoded into the score but then  
> you lose more score precision again (see above).

I'm having an NPE with the query who's toString gives:

  QueryMatchMonitor (QueryMatchMonitor ((title-fr:segm~0.5 title- 
phonetic-fr:SKM~0.5^0.8)) QueryMatchMonitor (((title-en:segm~0.5 title- 
phonetic-en:SKM~0.5^0.8))^0.95) QueryMatchMonitor (((title-de:segm~0.5  
title-phonetic-de:SKM~0.5^0.8))^0.9025) QueryMatchMonitor (((title- 
en:segm~0.5 title-phonetic-en:SKM~0.5^0.8))^0.85737497))

at

java.lang.NullPointerException
	at org.apache.lucene.search.FlagRecordingQuery 
$FlagRecordingQueryWeight.scorer(FlagRecordingQuery.java:104)
	at org.apache.lucene.search.BooleanQuery 
$BooleanWeight.scorer(BooleanQuery.java:297)
	at org.apache.lucene.search.FlagCombiningQuery 
$FlagCombiningQueryWeight.scorer(FlagCombiningQuery.java:100)
	at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java: 
246)
	at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java: 
173)
	at org.apache.lucene.search.Searcher.search(Searcher.java:181)
	at org.apache.lucene.search.Searcher.search(Searcher.java:191)

(but note that I removed explain from my FlagCombiningQuery; what's  
null is the delegateScorer).
Any clue?

paul
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