Re: Want explanation on lucene norms

[Adrien Grand <jp...@gmail.com>]

Hi,

Norms are inputs to the score that are independent from the query. It
is typically computed as a function of the number of terms of a
document: the more terms, the higher the normalization factor and the
lower the score.

Lucene computes and indexes length normalization factors automatically
for Text fields at index-time, and automatically uses them at search
time. There is nothing to do. The way normalization scores are
computed and folded into the final score is controlled by the
org.apache.lucene.search.similarities.Similarity.

Boosts are factors to the score that are independent from the
document. You can set them on a query via Lucene's
org.apache.lucene.search.BoostQuery. (Note that old Lucene versions
had a concept of index-time boosts, which would get combined with the
length normalization factor, but it was not recommended and it has
been removed.)

On Mon, Dec 20, 2021 at 6:08 PM Sowmiya M 4085 <so...@gmail.com> wrote:
>
> I just want to know what is norms in lucene 4.10.4.
> How to implement norms in a program.
> What are their types.
> What is the difference between boost and norms?
> Sample programs on norms



-- 
Adrien

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