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https://issues.apache.org/jira/browse/STATISTICS-71?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17739367#comment-17739367
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Gilles Sadowski commented on STATISTICS-71:
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bq. [...] for a simple statistic (min, max, sum) then computing the count is a
waste of resources.
I imagine than an increment by one is a marginal cost wrt the mechanics of
streams.
Even it is not necessary for computing the value, the count may be an
information needed by many users.
bq. [...] you only require one [count].
Indeed, recomputing the same values several times would indicate a design
problem.
What about {{Count}} being a {{DoubleStorelessStatistics}}, on which other(s)
could depend?
When using a "shared" {{Count}} instance (e.g. in a {{SummaryStatistics}}),
we'll have to ensure that all individual statistics can only be updated
together.
> Implementation of Univariate Statistics
> ---------------------------------------
>
> Key: STATISTICS-71
> URL: https://issues.apache.org/jira/browse/STATISTICS-71
> Project: Commons Statistics
> Issue Type: Task
> Components: descriptive
> Reporter: Anirudh Joshi
> Priority: Minor
> Labels: gsoc, gsoc2023
>
> Jira ticket to track the implementation of the Univariate statistics required
> for the updated SummaryStatistics API.
> The implementation would be "storeless". It should be used for calculating
> statistics that can be computed in one pass through the data without storing
> the sample values.
> Currently I have the definition of API as (this might evolve as I continue
> working)
> {code:java}
> public interface DoubleStorelessUnivariateStatistic extends DoubleSupplier {
> DoubleStorelessUnivariateStatistic add(double v);
> long getCount();
> void combine(StorelessUnivariateStatistic other);
> } {code}
>
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