The stills first pass drew frames from a shared cursor and stopped when a shared counter
reached its target, which got two things wrong at once. The cursor walked the equally
spaced sample in ascending order, so stopping early read only its leading PREFIX - the
beam centre, distance and cell were fitted to the beginning of the run, not across it,
and the comment claiming otherwise was wrong. And where the stop landed depended on how
the workers happened to interleave, so the set of frames varied run to run: on the same
data at -N 32 and -N 8 the pass examined 483 and 457 frames and refined the detector
distance to 168.0481 and 168.0530 mm.
The sample is now cut into a fixed number of interleaved stripes, each stopping once it
has contributed its share. Every stripe spans the whole run, so an early stop no longer
biases the fit, and a stripe is processed identically whichever worker claims it - so
what gets examined depends only on the data, not on timing and not on -N. The same three
runs now give 451 frames examined and 168.0452 mm, identically.
The bundle selection was order-dependent too: frames are collected in worker-completion
order and sorted by spot count with a non-stable sort, so equally strong frames swapped
places between runs. They carry their image ordinal now and it breaks the tie.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5
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