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From Erick Erickson <erickerick...@gmail.com>
Subject Re: two word phrase search using dismax
Date Mon, 05 Dec 2011 13:51:53 GMT
Have you looked at the "pf" (phrase fields)
parameter of edismax?

http://wiki.apache.org/solr/DisMaxQParserPlugin#pf_.28Phrase_Fields.29

Best
Erick

On Sat, Dec 3, 2011 at 7:04 PM,  <alxsss@aim.com> wrote:
> Hello,
>
> Here is my request handler
>
> <requestHandler name="search" class="solr.SearchHandler" >
> <lst name="defaults">
> <str name="defType">edismax</str>
> <str name="echoParams">explicit</str>
> <float name="tie">0.01</float>
> <str name="qf">site^1.5 content^0.5 title^1.2</str>
> <str name="pf">site^1.5 content^0.5 title^1.2</str>
> <str name="fl">id,title, site</str>
> <str name="mm">2&lt;-1 5&lt;-2 6&lt;90%</str>
> <int name="ps">300</int>
> <bool name="hl">true</bool>
> <str name="q.alt">*:*</str>
> <str name="hl.fl">content</str>
> <str name="f.title.hl.fragsize">0</str>
> <str name="hl.fragsize">165</str>
> <str name="f.title.hl.alternateField">title</str>
> <str name="f.url.hl.fragsize">0</str>
> <str name="f.url.hl.alternateField">url</str>
> <str name="f.content.hl.fragmenter">regex</str>
> </lst>
> </requestHandler>
>
> I have made a few tests with debugQuery and realised that for two word phrases, solr
takes the first word and gives it a score according to qf param then takes the second word
and gives it score and etc, but not to the whole phrase. That is why if one of the words is
in the title and one of them in the content then this doc is given higher score than the one
that has both words in the content but none in the title.
>
> Ideally, I want to achieve the following order.
> 1. If one (or both) of the words are in field site, then it must be given higher score.
> 2. Then come docs with both words in the title.
> 3. Next, docs with both words in the content.
> 4. And finally docs having either of words in the title and content.
>
> I tried to change mm param to <str name="mm">1&lt;-1 5&lt;-2 6&lt;90%</str>
> This allows to achieve 1,4 but not 2,3
>
> Thanks.
> Alex.
>
>
>
>
>
>
>
>
>
>
>
>
> -----Original Message-----
> From: Chris Hostetter <hossman_lucene@fucit.org>
> To: solr-user <solr-user@lucene.apache.org>
> Sent: Thu, Nov 17, 2011 2:17 pm
> Subject: Re: two word phrase search using dismax
>
>
>
>
> : After putting the same score for title and content in qf filed, docs
>
> : with both words in content moved to fifth place. The doc in the first,
>
> : third and fourth places still have only one of the words in content and
>
> : title. The doc in the second place has one of the words in title and
>
> : both words in the content but in different places not together.
>
>
>
> details matter -- if you send futher followup mails the full details of
>
> your dismax options and the score explanations for debugQuery are
>
> neccessary to be sure people understand what you are describing (a
>
> snapshot of reality is far more valuable then a vague description of
>
> reality)
>
>
>
> off hand what you are describing sounds correct -- this is what the
>
> dismax parser is really designed to do.
>
>
>
> even if you have given both title and content equal boosts, your title
>
> field is probably shorter then your content field, so words matching once
>
> in title are likly to score higher then the same word matching once in
>
> content due to length normalization -- and unless you set the "tie" param
>
> to something really high, the score contribution from the highest scoring
>
> field (in this case title) will be the dominant factor in the score (it's
>
> disjunction *max* by default ... if you make tie=1 then it's disjunction
>
> *sum*)
>
>
>
> you haven't mentioned anything about hte "pf" param at all which i can
>
> only assume means you aren't using it -- the pf param is how you configure
>
> that scores should be increased if/when all of the words in teh query
>
> string appear together.  I would suggest putting all of the fields in your
>
> "qf" param in your "pf" param as well.
>
>
>
>
>
> -Hoss
>
>
>

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