- Summary:
Fix bugzilla bug 131668.
- Bugzilla Bug (s) Resolved:
[131668] The function Total.percentile() works out the wrong result
- Description:
Excel uses its own formula to calculate the percentile value. The formula can
be explained by the following pseudocode:
Say, if you want pct-th percentile from acading
array a[],
k=Math.floor((pct/4)*(n-1))+1)
f=(pct/4)*(n-1))+1 - k; // We also need
to calculate fraction:
ad = a[k]+(f*(a[k+1]-a[k])) //Then we can
calculate out the adjustment:
result = a[k] + ad; //Finally we get the
result.
The original implementation of percentile and quartile
total function failed to comply with this rule.
The bug is fixed in source.
- Tests Description:
Unit test.
- Files Edited:
"/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/aggregation/rank/PercentileAccumulator.java"
"/org.eclipse.birt.data/test/org/eclipse/birt/data/engine/aggregation/TotalTest.java"
- Files Added:
N/A
- Files Deleted:
N/A
- Notes to Build Team:
N/A
- Notes to Developers:
N/A
- Notes to QA:
N/A
- Notes to Documentation:
N/A
