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https://issues.apache.org/jira/browse/LUCENE-1360?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12987824#action_12987824
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Robert Muir commented on LUCENE-1360:
-------------------------------------
The only issue i have with the floatToByte52 is its a 'trap' so to speak,
that if you use it on a too-long field (or maybe too-small boost), you end
out with a norm of zero.
In my opinion, the whole purpose of per-field support is so that you don't
have to make these sort of tradeoffs, but i imagine someone could
use an inappropriate similarity/schema sometime (misconfiguration)
to degrade better in this case, I suggest this change, which decodes 0-byte
norms
as if they were 1-byte, so that scores won't be zeroed in the misconfiguration
case...
change:
{noformat}
static {
for (int i = 0; i < 256; i++)
NORM_TABLE[i] = SmallFloat.byte52ToFloat((byte)i);
}
{noformat}
to:
{noformat}
static {
NORM_TABLE[0] = SmallFloat.byte52ToFloat((byte)1);
for (int i = 1; i < 256; i++)
NORM_TABLE[i] = SmallFloat.byte52ToFloat((byte)i);
}
{noformat}
> A Similarity class which has unique length norms for numTerms <= 10
> -------------------------------------------------------------------
>
> Key: LUCENE-1360
> URL: https://issues.apache.org/jira/browse/LUCENE-1360
> Project: Lucene - Java
> Issue Type: Improvement
> Components: Query/Scoring
> Reporter: Sean Timm
> Assignee: Otis Gospodnetic
> Priority: Trivial
> Attachments: LUCENE-1360.patch, LUCENE-1380 visualization.pdf,
> ShortFieldNormSimilarity.java
>
>
> A Similarity class which extends DefaultSimilarity and simply overrides
> lengthNorm. lengthNorm is implemented as a lookup for numTerms <= 10, else
> as {{1/sqrt(numTerms)}}. This is to avoid term counts below 11 from having
> the same lengthNorm after stored as a single byte in the index.
> This is useful if your search is only on short fields such as titles or
> product descriptions.
> See mailing list discussion:
> http://www.nabble.com/How-to-boost-the-score-higher-in-case-user-query-matches-entire-field-value-than-just-some-words-within-a-field-td19079221.html
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