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https://issues.apache.org/jira/browse/MATH-1065?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13830983#comment-13830983
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Phil Steitz commented on MATH-1065:
-----------------------------------

I think the intent of this class is to represent a discrete, but real-valued 
distribution.  EnumeratedDistributions are discrete distributions with a 
finite, "enumerated" set of values.  The problem here is that 
EnumeratedRealDistribution extends AbstractRealDistribution and does not 
override the default inverse cum method that basically assumes a continuous 
distribution.  What it should implement is something like the discrete 
algorithm implemented in AbstractIntegerDistribution.  I agree this is a bug 
and I think the correct fix is to implement inverseCumulativeProbability in 
EnumeratedRealDistribution by adapting the implementation of this method in 
AbstractIntegerDistribution.

> EnumeratedRealDistribution.inverseCumulativeProbability returns values not in 
> the samples set
> ---------------------------------------------------------------------------------------------
>
>                 Key: MATH-1065
>                 URL: https://issues.apache.org/jira/browse/MATH-1065
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 3.2
>            Reporter: matteodg
>             Fix For: 4.0, 3.3
>
>         Attachments: EnumeratedRealDistributionTest.java
>
>
> The method EnumeratedRealDistribution.inverseCumulativeProbability() 
> sometimes returns values that are not in the initial samples domain...
> I will attach a test to exploit this bug.



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