The stills scale/merge after the image loop was almost entirely serial:
- every scaling-reference merge (MergeAll: the per-image scaling reference and the two
partiality post-refinement references) ran French-Wilson single-threaded on its export,
about 3 s each, and assigned free-R flags - neither is read by a reference, which uses I
only. MergeAll now exports intensities alone (MergeOnTheFly::ExportIntensities).
- the merge accumulated into a std::map; it is now an unordered_map exported in key order,
which is the std::map order.
- AddImage, the error-model collection and the R_meas pass of MergeStats did the
per-observation work (systematic-absence test, ASU key, filters, error-model sigma,
outlier test, merged-I lookup) in one serial loop. They now reduce a block of images in
parallel and consume it in image order (ReduceImagesInOrder), so every floating-point
sum, half-set choice and hash-map insertion is made in the serial order.
Measured on a 25k-frame XFEL stills run (box loaded, load 9-14): merge P1 19.0 -> 7.1 s,
final-group merge 27.7 -> 13.2 s; on a second run 23.4 -> 7.7 s and 29.7 -> 13.6 s.
mtz/unmerged mtz data, hkl, cif and report identical on both runs, mx and --mode scale.
New test MergeOnTheFly_AddImagesIsTheSerialMerge checks the parallel merge against the
serial loop across a block boundary.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5.5
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