Clear() reallocated sum and count but left sum2 as the constructor had
sized it. Every caller reuses one profile across the images of a dataset
(rugnux keeps one per worker, the viewer one per view), so the squares
kept accumulating while the means restarted at zero: the per-image
standard deviation written to /entry/azint and shown in the plots was
meaningless from the second image on, and grew without bound over a run.
The size mismatch was the sharper edge. Clearing to a mapping with a
different bin count left sum2 shorter than sum, and GetStd() and
operator+= then read past its end - reachable in the viewer by opening a
dataset with a wider q range than the one before it.
Both are covered by tests: the same frame twice with a Clear() in
between has to give the same standard deviation, and a profile cleared
to a wider mapping has to report the right value in a bin that only the
wider mapping has.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5
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