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https://issues.apache.org/jira/browse/MATH-1131?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14043857#comment-14043857
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Thomas Neidhart commented on MATH-1131:
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I did briefly debug the example and indeed the calculation hangs when calling
roundedK, or more precisely in createH.
There powers of BigFraction objects are created with really big numerators and
denominators. Some of the calculations later on take then forever because of
this, e.g. when internally calculating the gcd.
Looking at the implementation from the referenced paper, there the H values are
computed with double precision. Was there a specific reason to use BigFraction
in our implementation? Is there a specific need for that level of accuracy for
the Kolmogorov-Smirnov Test? The other inference tests do not seem to be so
stringent.
It looks like there is no easy way to limit the maxDenominator when calling
multiply() as it is possible when creating a BigFraction object.
> Kolmogorov-Smirnov Tests takes 'forever' on 10,000 item dataset
> ---------------------------------------------------------------
>
> Key: MATH-1131
> URL: https://issues.apache.org/jira/browse/MATH-1131
> Project: Commons Math
> Issue Type: Bug
> Affects Versions: 3.3
> Environment: Java 8
> Reporter: Schalk W. Cronjé
> Attachments: 1.txt, ReproduceKsIssue.groovy, ReproduceKsIssue.java
>
>
> I have code simplified to the following:
> KolmogorovSmirnovTest kst = new KolmogorovSmirnovTest();
> NormalDistribution nd = new NormalDistribution(mean,stddev);
> kst.kolmogorovSmirnovTest(nd,dataset)
> I find that for my dataset of 10,000 items, the call to kolmogorovSmirnovTest
> takes 'forever'. It has not returned after nearly 15minutes and in one my my
> tests has gone over 150MB in memory usage.
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