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https://issues.apache.org/jira/browse/STATISTICS-90?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17937409#comment-17937409
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Alex Herbert commented on STATISTICS-90:
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I have added the range functions to the master branch:
Descriptive statistic instances are created using {{{}ofRange{}}}.
The median and quantile use {{{}evaluateRange{}}}.
E.g.
{code:java}
int[] values = {1, 1, 2, 3, 5, 8, 13, 21};
IntMax max = IntMax.ofRange(values, 3, 6); // max=8
double median = Median.withDefaults().evaluateRange(values, 3, 6); //
median=5.0
{code}
Note: Overload of the {{evaluate}} method for the quantile with range arguments
can lead to a potential user error due to the use of varargs for the
probabilities:
{code:java}
// Existing
public double[] evaluate(int[] values, double... p);
// Overloaded
public double[] evaluate(int[] values, int from, int to, double... p);
// Should this be a range, or the quantiles [0.0, 1.0, 0.5]?
double[] x = ...
Quantile.withDefaults().evaluate(x, 0, 1, 0.5)
{code}
In this case it is a more consistent API to include Range in the method name.
> Support statistic creation using an array range
> -----------------------------------------------
>
> Key: STATISTICS-90
> URL: https://issues.apache.org/jira/browse/STATISTICS-90
> Project: Commons Statistics
> Issue Type: New Feature
> Components: descriptive
> Affects Versions: 1.1
> Reporter: Alex Herbert
> Priority: Minor
>
> Add support for using part of an array to create statistics:
> {code:java}
> double[] x = ...
> int from = ...
> int to = ...
> Min.ofRange(x, from, to);
> DoubleStatistics.ofRange(EnumSet.of(Statistic.MIN), x, from, to);{code}
> This change should have no impact on performance for full length arrays and
> improve memory consumption by avoiding array copies on sub-ranges. Results
> from STATISTICS-89 indicate a non-negligible performance gain for fast
> computing statistics.
> Note: Support for sub-ranges is present in the Commons Math
> UnivariateStatistic interface. This change will allow supporting replacement
> of the Math API with Statistics.
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