[MAHOUT-692] OnlineSummarizer does not tolerate fewer than 100 samples

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.4
• Fix Version/s: 0.6
• Assignee: Ted Dunning
• Reporter: Paul Baclace
• Created: 10/May/11 23:39
• Updated: 09/Feb/12 14:00
• Resolved: 04/Jun/11 16:15

Description

If fewer than 100 samples are add()ed to an instance of org.apache.mahout.math.stats.OnlineSummarizer an exception will be thrown during a sort when getQuartile() is called:

Caused by: java.lang.IndexOutOfBoundsException: from: 0, to: 99, size=89

at org.apache.mahout.math.list.AbstractList.checkRangeFromTo(AbstractList.java:87)
at org.apache.mahout.math.list.DoubleArrayList.sortFromTo(DoubleArrayList.java:573)
at org.apache.mahout.math.stats.OnlineSummarizer.sort(OnlineSummarizer.java:116)
at org.apache.mahout.math.stats.OnlineSummarizer.getQuartile(OnlineSummarizer.java:129)

The problem is that sort is on index range 0,99 but 0,n-1 should be used.