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Posted to java-user@lucene.apache.org by Mossaab Bagdouri <ba...@yahoo.fr.INVALID> on 2016/11/09 19:25:04 UTC
Isn't fieldLength in BM25 supposed to be an integer?
Hi,
On Lucene 6.2.1, I have the following explain output for a document that
contain two words. I'm wondering why the value of fieldLength is not 2.
A related question was posted on S.O. two years ago:
http://stackoverflow.com/questions/22194920
23.637165 = sum of:
10.065297 = weight(title:googl in 401658357) [BM25Similarity], result of:
10.065297 = score(doc=401658357,freq=1.0 = termFreq=1.0
), product of:
7.3866553 = idf(docFreq=414179, docCount=668609139)
1.3626325 = tfNorm, computed from:
1.0 = termFreq=1.0
1.2 = parameter k1
0.75 = parameter b
7.3254013 = avgFieldLength
2.56 = fieldLength
13.571868 = weight(title:hangout in 401658357) [BM25Similarity], result
of:
13.571868 = score(doc=401658357,freq=1.0 = termFreq=1.0
), product of:
9.960035 = idf(docFreq=31592, docCount=668609139)
1.3626325 = tfNorm, computed from:
1.0 = termFreq=1.0
1.2 = parameter k1
0.75 = parameter b
7.3254013 = avgFieldLength
2.56 = fieldLength
Regards,
Mossaab
Re: Isn't fieldLength in BM25 supposed to be an integer?
Posted by Ahmet Arslan <io...@yahoo.com.INVALID>.
Hi Mossaab,
Probably due to the encodeNormValue/decodeNormValue transformation of the document length.
Please see the aforementioned methods in BM25Similarity.java
Ahmet
On Wednesday, November 9, 2016 10:25 PM, Mossaab Bagdouri <ba...@yahoo.fr.INVALID> wrote:
Hi,
On Lucene 6.2.1, I have the following explain output for a document that
contain two words. I'm wondering why the value of fieldLength is not 2.
A related question was posted on S.O. two years ago:
http://stackoverflow.com/questions/22194920
23.637165 = sum of:
10.065297 = weight(title:googl in 401658357) [BM25Similarity], result of:
10.065297 = score(doc=401658357,freq=1.0 = termFreq=1.0
), product of:
7.3866553 = idf(docFreq=414179, docCount=668609139)
1.3626325 = tfNorm, computed from:
1.0 = termFreq=1.0
1.2 = parameter k1
0.75 = parameter b
7.3254013 = avgFieldLength
2.56 = fieldLength
13.571868 = weight(title:hangout in 401658357) [BM25Similarity], result
of:
13.571868 = score(doc=401658357,freq=1.0 = termFreq=1.0
), product of:
9.960035 = idf(docFreq=31592, docCount=668609139)
1.3626325 = tfNorm, computed from:
1.0 = termFreq=1.0
1.2 = parameter k1
0.75 = parameter b
7.3254013 = avgFieldLength
2.56 = fieldLength
Regards,
Mossaab
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