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https://issues.apache.org/jira/browse/LUCENE-3440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13114402#comment-13114402
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Koji Sekiguchi commented on LUCENE-3440:
----------------------------------------
{quote}
Hm, I thought about something like that:
{code:xml}
<highlighting>
<fragmentsBuilder name="ordered"
class="org.apache.solr.highlight.ScoreOrderFragmentsBuilder" default="false"/>
<fragmentsBuilder name="weighted"
class="org.apache.solr.highlight.WeightOrderFragmentsBuilder" default="true"/>
</highlighting>
{code}
For Solr-users (like me). If somebody would like to use the boost-based
ordering, he could. Maybe, for some use-cases the boost-based approach is
better than the weighted one.
{quote}
I thought that, too. But I saw the following in the patch:
{code}
public List<WeightedFragInfo> getWeightedFragInfoList( List<WeightedFragInfo>
src ) {
Collections.sort( src, new ScoreComparator() );
// Collections.sort( src, new WeightComparator() );
return src;
}
{code}
And I thought you wanted to use WeightComparator from
ScoreOrderFragmentsBuilder. :)
Well now, let's introduce WeightOrderFragmentsBuilder.
> FastVectorHighlighter: IDF-weighted terms for ordered fragments
> ----------------------------------------------------------------
>
> Key: LUCENE-3440
> URL: https://issues.apache.org/jira/browse/LUCENE-3440
> Project: Lucene - Java
> Issue Type: Improvement
> Components: modules/highlighter
> Affects Versions: 3.5, 4.0
> Reporter: sebastian L.
> Priority: Minor
> Labels: FastVectorHighlighter
> Fix For: 3.5, 4.0
>
> Attachments: LUCENE-3.5-SNAPSHOT-3440-3.patch,
> LUCENE-4.0-SNAPSHOT-3440-3.patch
>
>
> The FastVectorHighlighter uses for every term found in a fragment an equal
> weight, which causes a higher ranking for fragments with a high number of
> words or, in the worst case, a high number of very common words than
> fragments that contains *all* of the terms used in the original query.
> This patch provides ordered fragments with IDF-weighted terms:
> total weight = total weight + IDF for unique term per fragment * boost of
> query;
> The ranking-formula should be the same, or at least similar, to that one used
> in org.apache.lucene.search.highlight.QueryTermScorer.
> The patch is simple, but it works for us.
> Some ideas:
> - A better approach would be moving the whole fragments-scoring into a
> separate class.
> - Switch scoring via parameter
> - Exact phrases should be given a even better score, regardless if a
> phrase-query was executed or not
> - edismax/dismax-parameters pf, ps and pf^boost should be observed and
> corresponding fragments should be ranked higher
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