[MAHOUT-557] Bug in Auc computation

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.4
• Fix Version/s: 0.5
• Assignee: Unassigned
• Reporter: Ted Dunning
• Created: 30/Nov/10 04:58
• Updated: 31/Jan/24 22:12
• Resolved: 12/Dec/10 22:41

Description

From Anil:

Another bug: in Auc.java
Classifier Evaluation :

when the scores are tied -
...

// how many negatives are tied?
int k0 = 0;
while (i0 < n0 && v0 == tieScore)

Unknown macro: { k0++; i0++; v0 = scores[0].get(i0); }

// and how many positives
int k1 = 0;
while (i1 < n1 && v1 == tieScore)

Unknown macro: { k1++; i1++; v1 = scores[1].get(i1); }

It sometimes goes Index out of bounds: Increment operation should be after accessing it

while (i0 < n0 && v0 == tieScore)

Unknown macro: { v0 = scores[0].get(i0); k0++; i0++; }

// and how many positives
int k1 = 0;
while (i1 < n1 && v1 == tieScore)

Unknown macro: { v1 = scores[1].get(i1); k1++; i1++; }

Verily, he speaks truth.