[Xapian-tickets] [Xapian] #435: Remove score_evenness() functions in matchspy.h

[Xapian]

#435: Remove score_evenness() functions in matchspy.h
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 Reporter:  richard  |       Owner:  richard  
     Type:  task     |      Status:  new      
 Priority:  normal   |   Milestone:  1.1.4    
Component:  Other    |     Version:  SVN trunk
 Severity:  normal   |    Keywords:           
Blockedby:           |    Platform:  All      
 Blocking:           |  
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 The score_evenness() functions in matchspy.h were intended to be a way to
 determine how good a particular set of facet results is.  However, after
 experience using the facet support in real-life situations for a couple of
 years, I'm very dubious that they ever give useful results: each time I've
 tested them out, the choice of facets produced by score_evenness() has
 been pretty poor: a manual fixed choice of order of facets has always been
 an improvement.

 It's possible that the calculation from score_evenness() might be useful
 in some situations I've not come across, but it's not hard to implement an
 equivalent outside Xapian.

 I therefore propose to move the score_evenness() functions out of Xapian
 trunk.  I'd leave them on the !MatchSpy branch for now, but if we've not
 found a real use for them by the time we've worked out a clean API for the
 !MultiValueCountMatchSpy, I think we can drop them.

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Ticket URL: <http://trac.xapian.org/ticket/435>
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