how is calculated score in group queries?

[Vincenzo D'Amore]

Hi all,

I have a couple of questions about grouping, I hope you can help me.

I'm trying to understand how is calculated group score in group queries.

So, I did my home work and it seems that group score is taken from score of
first document for each group found, i.e.:

<lst name="grouped">
   <lst name="slug_preferenziale">
      <int name="matches">3653</int>
        <arr name="groups">
          <lst>
             <str name="groupValue">
                       /xxxxxx/yyyyyyy/xxxxxxxx
             </str>
             <result name="doclist" numFound="437" start="0"
maxScore="0.775318">
                <doc>
                   <str name="namesearch">
                        Document title
                   </str>
                        <float name="score">0.775318</float>
                 </doc>
[omissis]

So for all the groups, what I see is that maxScore is the same value of
first document into the returned group. Am'I right?

I'm still using Solr 4.8.1, any chance this thing is changed/fixed in the
early releases?

I as this because reading the documentation I see now we should prefer
"Collapse and Expand", even if not in all cases we can use it... not clear
when.

So what's the difference? Can be explained with a real word example?

Best regards and thanks for all the time you will spent with me,
Vincenzo


-- 
Vincenzo D'Amore
email: v.dam...@gmail.com
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