rc182 kept every profile intensity above a box sum of more than 20 sigmas. That removed the
fallback on strong spots whose profile reads a few per cent above the box (the r1 disk misses the
tail), but it also kept profiles that read 1.5-30x the box sum. Those are not tails: the fit grid
reaches out to r2 and picks up signal the disk does not hold - a second lattice, split spots, an
unpredicted neighbour, a dead detector edge. Per-reflection dumps showed them on the sets that
lost (on 7bgu 99% of the strong reflections at the outer detector edge, with a negative background;
on split and multi-crystal sets 10-25% of the strong reflections, at every resolution), while on the
sets that gained the kept reflections read what the strong population reads in their shell
(typically 1.03-1.20). Against the symmetry mates in 9fhc's unmerged output the rc182 guard added
~14000 observations more than 100% off.
The guard now falls back above the box sum only when the profile exceeds it by more than the
10-sigma margin plus 25% of the box sum (PROFILE_SUMMATION_MAX_TAIL). Below the box sum it is
unchanged. Weak reflections see a margin of 10 sigma plus at most 5 sigma, so the runaway guard
stands.
CPU-only, against the rc182 guard: 9fhc goes back to d_min 1.90 / ISa 11.1 (rc182: 1.95 / 13.5,
before rc182: 1.90 / 10.8); 7kcn R_meas 6.39% and 6v2r ISa 36.6 keep rc182's gain in full. GPU
equals CPU on 7kcn and 6v2r.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UqXYdL4qBGYRiSXSGXfCLu
leonarski_fandClaude Opus 5.5
f31ac225e9