Refine all per-image scales, per-image mosaicities and the shared per-HKL
true intensities (plus the global wedge) together in one Ceres problem
(GlobalScale.{h,cpp}, GlobalScaleCeres), as an alternative to the existing
alternating merge-then-scale-each-image loop. The result feeds back into each
reflection's image_scale_corr exactly as ScaleOnTheFly does, so the rot3d
combine and MergeOnTheFly run unchanged and every metric stays comparable.
On HEWL crystal 2 the joint fit converges to the same place as the alternating
loop (anomalous S-peak vs XDS 0.53x -> 0.54x, ISa 9.4 both), confirming the
alternating path already reaches the joint optimum. Kept as a validated
alternative and the home for future global corrections.
A shared quadratic absorption surface in detector position was prototyped here
and dropped: it fit large non-physical coefficients (radially degenerate with
the per-HKL resolution structure), lowered the scaling-fit residual but raised
the error-model b (ISa 9.4 -> 7.3) and did not improve anomalous accuracy.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
leonarski_fandClaude Opus 4.8
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