Re: 答复: About the Sorting of Groups during Grouping by

[Tom Burton-West <tb...@umich.edu>]

Hello Oliver,

We are very interested in group sorting based on some aggregation function
also. Would you consider contributing your code to Lucene, or posting your
results?

Tom

Tom Burton-West
Information Retrieval Programmer
Digital Library Production Service
University of Michigan Library
http://www.hathitrust.org/blogs/large-scale-search



On Mon, Feb 11, 2013 at 3:55 PM, Oliver Xu <ol...@gmail.com> wrote:

> Right. I understand that the TermFirstPassGroupingCollector is extended
> from
> Collector class too. Let me try.
>
> Many thanks to you!
>
> -----邮件原件-----
> 发件人: martijn.is.hier@gmail.com [mailto:martijn.is.hier@gmail.com] 代表
> Martijn v Groningen
> 发送时间: 2013年2月11日 19:29
> 收件人: java-user@lucene.apache.org
> 主题: Re: About the Sorting of Groups during Grouping by
>
> Hi,
>
> My purpose is trying to sort the groups based on some way of aggregation
> > values of the scores of all the documents in each group, such as their
> sums
> > or averages.
> >
> At the moment this isn't possible out of the box. You could implement your
> own
> collector that collects these statistics per group. Embed the the result in
> a FieldComparator
> that you use as custom sort in the TermFirstPassGroupingCollector. But this
> is just a wild idea.
>
>
> >
> >
> >
> > There is an 'Enum TopGroups.ScoreMergeMode' in the
> > org.apache.lucene.search.grouping package with the description as "How
> the
> > GroupDocs score (if any) should be merged." Is it exactly introduced for
> > the
> > purpose above? If yes, how to included it into the grouping code? A demo
> > code would be perfect.
> >
> The enum is actually only used by the join module
> (ToParentBlockJoinCollector).
> The enum controls how the block join group scores are aggregated during a
> distributed search.
>
> Martijn
>
>
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