Akash Srivastava created MATH-1495:
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Summary: 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
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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