Gnats 5614: Additional fix to SUM for incomplete initial and final time aggregations
Phil, 4-30-2015 (b)

In the Time Aggregation Series Slot, incomplete time aggregations at the beginning or end of the source series slot were causing incorrect SUM aggregation results. This was resolved by expanding the source time range to complete aggregation slot timesteps, effectively providing NaNs for the missing timesteps.

This change had no effect on the AVE computation, where NaN values are ignored. But it does effect the FIRST and LAST computations in the obvious way, which seems reasonable.

Below are illustrations of the SUM and AVE functions, before and after this change. For AVE, the arithmetic with which the result is computed is also provided. CLICK THUMBNAILS to see full image.

SUM Annual Agg of Monthly Values Monthly Agg of Daily Values
Incomplete
Initial Agg		 InitialPartialAgg-AnnualSum.png InitialPartialAgg-MonthlySum.png
Incomplete
Final Agg		 FinalPartialAgg-AnnualSum.png FinalPartialAgg-MonthlySum.png

AVE
computation
(no change)		 InitialPartialAgg-AnnualAve.png

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