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https://issues.apache.org/jira/browse/MATH-1495?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16906308#comment-16906308
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Akash Srivastava commented on MATH-1495:
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I have cloned the Apache commons math repository
> Calling NaturalRanking#rank() on an array of all NaNs throws a misleading
> ArrayIndexOutOfBoundsException when the NanStrategy is REMOVED
> ----------------------------------------------------------------------------------------------------------------------------------------
>
> Key: MATH-1495
> URL: https://issues.apache.org/jira/browse/MATH-1495
> Project: Commons Math
> Issue Type: Bug
> Reporter: Akash Srivastava
> Priority: Major
>
> Consider the following code:
> {code:java}
> import org.apache.commons.math3.stat.ranking.NaNStrategy;
> import org.apache.commons.math3.stat.ranking.NaturalRanking;
> import org.apache.commons.math3.stat.ranking.TiesStrategy;
> class AllNaNException{
> public NaturalRanking naturalranking;
> public double[] AllNaNArray(){
> naturalranking = new NaturalRanking(NaNStrategy.REMOVED,
> TiesStrategy.AVERAGE);
> double[] x = {Double.NaN, Double.NaN};
> double[] y = naturalranking.rank(x);
> return y;
> }
> public static void main(String[] args) {
> AllNaNException a = new AllNaNException();
> double[] res = a.bug();
> System.out.println(res[0] + "," + res[1]);
> }
> }
> {code}
> Compiled it by: javac -cp /usr/share/java/commons-math3-3.6.1.jar tryit.java
> Executed it by: java -cp /usr/share/java/commons-math3-3.6.1.jar:. tryit
>
> Output:
> {code:java}
> Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0
> at
> org.apache.commons.math3.stat.ranking.NaturalRanking.rank(NaturalRanking.java:231)
> at tryit.bug(tryit.java:9)
> at tryit.main(tryit.java:14)
> {code}
>
> Currently, calling NaturalRanking#rank() on an array of all NaNs throws a
> misleading ArrayIndexOutOfBoundsException when the NanStrategy is REMOVED. I
> am unsure what outcome the user should expect in code like the test case I
> have provided below. Can you shed some light on this? I am happy to write a
> pull request once I know what fix would be best. I think throwing an
> IllegalArgumentException or returning an empty array would be more apt in
> this case.
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