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Combined time and relevant sorting is the "magic solution" to ranking results which we believe will deliver the best results, especially for projects where the most recent items are usually more important than older inforrmation |
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relevance_score
: original relevance score of document wrt the querybase
: parameter use to adjust the impact of relevance. Higher this value, higher impact of relevance score (if you set this value very high, e.g 100, you can see impact of time factor is very minor, relevance score contributes mostly in final score)range
: range of decay, higher this value, longer decay range (if range = 0 you will see final score depends only on relevance score)decay
: decay speed, higher this value, quicker decay value (if decay = 0 you will see final score depends only on relevance score)age_days
: number of days from now sincecreated_at
time of documents.
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Beside above parameters we introduce as well low_relevance
and old_period
parameters to handle edge cases where very new document with very low relevance or very old document with very high relevance should be always put at the end of result list. Default value is 180 days for old_period
and 0.25 for low_relevance;
looking at above curve of relevance scores you can see the relevance scores are quite flat after value 0.25)
How to Configure
This setting can be defined either using your browser, when you create a new project, using the Advanced Options or by changing the value of time_relevance in Squirro search results can be sorted in by time_relevance
as default on a per-project basis by using the Advanced Options.
The factors of ranking formula (base, range, decay, low_relevance, old_period) can be tuned in in common.ini, in the [ranking] section, which can be set to;
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But why use not Elasticsearch's decay function?
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