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From Chris Hostetter <hossman_luc...@fucit.org>
Subject RE: How to get mapping of query terms to number of their occurrences in a doc?
Date Wed, 08 Feb 2006 18:04:20 GMT

: That's what I did, for debugging.  The query is "biology", and here's
: what the API tells me for term frequencies:
: biolog 15
: biologi 31
: biologist 4
:
: I actually see 13 occurrences of "biologist" and "biologists", 64
: occurrences of "biology", 27 occurrences of "biological".
:
: I see "inform 22" but the actual count of the word "information" in the
: document is 33.  But "ioniz 7" is correct.

I think I missunderstood what you ment when you said the counts don't
match up.  Are you comparing the number you get from that code with the
number of times you personally see the word in the source document before
it has been analyzed?

If so, then there could be a couple of things going on ... i would start
by using a tool like Luke to see the actual lists of Terms for each doc --
there may be something else your analyzer is doing that you don't realize.

It's also possible that you are hitting the maxFieldLength in the
IndexWriter ... when that happens IndexWriter throws away any remaining
tokens, so if your documenst are really large.

Lastly, I would add a *lot* more debugging to your code.  Print out the
contents of "terms", when you loop over "tfvs" print out the field and the
full list of strTerms, in the inner most loop when you incriment the
count, print out the field/text/and count.

that's the best advise i have for spotting what's wrong.



: ________________________________
:
: From: Chris Hostetter [mailto:hossman_lucene@fucit.org]
: Sent: Tue 2/7/2006 4:10 PM
: To: java-user@lucene.apache.org
: Subject: Re: How to get mapping of query terms to number of their occurrences in a doc?
:
:
:
:
: A cursory reading of your code looks ok ... stemming shouldn't be an issue
: as long as your measure of success is comparing docs that match your
: orriginal query with the counts you get out.
:
: What i mean by that is that any stemming should have already been taken
: care of when your query object was constructed (either by you manually, or
: by QueryParser).  the direct equals comparisons you are dong should be
: fine.
:
: have you tried adding logging of the raw term field/text and the freq
: counts you get back to see if that helps you spot the problem?
:
:
: : Date: Mon, 6 Feb 2006 14:34:05 -0800
: : From: Dmitry Goldenberg <dmitry.goldenberg@weblayers.com>
: : Reply-To: java-user@lucene.apache.org
: : To: java-user@lucene.apache.org
: : Subject: How to get mapping of query terms to number of their occurrences
: :     in a doc?
: :
: : Given a query, I want to be able to, for each query term, get the number of occurrences
of the term.  I have tried what I'm including below and it does not seem to provide reliable
results.  Seems to work fine with exact matching but as soon as stemming kicks in, all bets
are off as to value of the number of occurrences returned.
: :
: : Any ideas, anyone?  Can this be written in a simpler and/or more efficient way?
: : Thanks -
: :
: :       int totalOccurrences = 0;
: :
: :       reader = IndexReader.open(getDirectory(indexDirPath));
: :       HashSet terms = new HashSet();
: :       query.extractTerms(terms);
: :
: :       TermFreqVector[] tfvs = reader.getTermFreqVectors(docId);
: :       if (tfvs != null) {
: :
: :         // For each term frequency vector (i.e. for each field)
: :         for (int i = 0; i < tfvs.length; i++) {
: :           String field = tfvs[i].getField();
: :           String[] strTerms = tfvs[i].getTerms();
: :           int[] tfs = tfvs[i].getTermFrequencies();
: :
: :           if (strTerms != null) {
: :
: :             // For each term in the query
: :             for (Iterator iter = terms.iterator(); iter.hasNext();) {
: :
: :               Term term = (Term) iter.next();
: :               // For each term in the vector
: :               for (int j = 0; j < strTerms.length; j++) {
: :
: :                 // If found the query term among the vector terms
: :                 if (field.equals(term.field()) && strTerms[j].equals(term.text()))
{
: :
: :                   // Add the term frequency to the total
: :                   totalOccurrences += tfs[j];
: :
: :                 }
: :               }
: :             }
: :           }
: :         }
: :       }
: :
:
:
:
: -Hoss
:
:
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:



-Hoss


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