SOLR-16291 : Decay function queries gauss,linear,exponential

[danrosher]

https://issues.apache.org/jira/browse/SOLR-16291

Description

This is a Solr version of the Decay functions [available in Elasticsearch ] (https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-function-score-query.html#function-decay )

Decay functions score a document with a function that decays depending on the distance of a numeric field value of the document from a user given origin. This is similar to a range query, but with smooth edges instead of boxes.

Solution

implemented as ValueSourceParsers

Tests

Test are in org.apache.solr.search.function.decayfunction for testing exponential, gauss and linear implementations

Checklist

Please review the following and check all that apply:

• [x] I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• [x] I have created a Jira issue and added the issue ID to my pull request title.
• [x] I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• [x] I have developed this patch against the main branch.
• [ ] I have run ./gradlew check.
• [x] I have added tests for my changes.
• [ ] I have added documentation for the Reference Guide

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[janhoy]

@risdenk Why do you think it is doing too much? As I interpret this, it will only parse the values for date (d) and geo fields (km), which is very user friendly. But if you wish you could still use it on pure numeric field and combine with other functions?

[github-actions[bot]]

This PR had no visible activity in the past 60 days, labeling it as stale. Any new activity will remove the stale label. To attract more reviewers, please tag someone or notify the [email protected] mailing list. Thank you for your contribution!

[epugh]

Hi all, this seems like a really nice addition to Solr... Assuming @danrosher is still up for adding the Ref Guide docs, this seems like a good capablity. Not sure how strongly you feel @risdenk on this versus the positive indication from @janhoy ? Be curious if there are some specificis that could be made to get this to a LGTM !