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From "Thomas Neidhart (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MATH-1203) getKernel fails for buckets with only multiple instances of the same value in random.EmpiricalDistribution
Date Sun, 08 Mar 2015 21:28:38 GMT

    [ https://issues.apache.org/jira/browse/MATH-1203?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14352272#comment-14352272
] 

Thomas Neidhart commented on MATH-1203:
---------------------------------------

I have seen that Phil fixed this issue, but there is still something wrong in case a bin has
a constant real distribution as kernel:

{code}
        final double[] data = {0, 0, 1, 1};
        EmpiricalDistribution dist = new EmpiricalDistribution(2);
        dist.load(data);

        System.out.println(dist.cumulativeProbability(0));
{code}

Will output NaN. I have seen this while taking a look, but did not yet have the time to further
dig into it.

> getKernel fails for buckets with only multiple instances of the same value in random.EmpiricalDistribution
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: MATH-1203
>                 URL: https://issues.apache.org/jira/browse/MATH-1203
>             Project: Commons Math
>          Issue Type: Bug
>    Affects Versions: 3.4, 3.4.1
>            Reporter: Kyle Kavanagh
>
> After loading a set of values into an EmpericalDistribution, assume that there's a case
where a single bin ONLY contains multiple instances of the same value.  In this case the standard
deviation will equal zero.  This will fail when getKernel attempts to create a NormalDistribution.
 The other case where stddev=0 is when there is only a single value in the bin, and this is
handled by returning a ConstantRealDistribution rather than a NormalDistrbution.
> See: https://issues.apache.org/jira/browse/MATH-984



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