The pre-scan's spot-shape estimate (spot_width::EstimateBandwidth) becomes the run's bandwidth where it
is significant (z > 3) and neither the file nor --bandwidth states one; an explicit value, including
--bandwidth 0, still wins. Everything that already reads GetBandwidthFWHM() - prediction, partiality,
the profile's radial width, the stencil growth, scaling - takes it from there. Below z 3 the bandwidth
stays unset, so monochromatic runs are bit-identical (12 mono sets checked on p.hkl md5).
The width tiers stop as soon as r80 settles, often at 15 frames and a few hundred spots, which is
too few for the slope. The pre-scan now keeps measuring spot shapes for the bandwidth alone until the
pool holds 1000 spots or the sample ends. Those extra frames feed neither r80 nor the powder
measurement, so r1..r3, powder and the spot-resolution quantiles are unchanged. Over the 68-set
battery plus the known mono controls (47 sets re-probed) no monochromatic set crosses z 3 (highest
lyso_x06da_5keV 2.0, insu 5-6 keV 1.7); the one new positive is 9z44 (ALS 8.2.1, multilayer
beamline, 0.38% at z 3.1 from 382 spots instead of z 1.0 from 94).
Two hidden b > 0 mode switches go, so the bandwidth acts continuously:
- the background clip default dropped from 4 to 3 sigma when a bandwidth was set. With the measured
bandwidth, clip 3 vs 4 on the MicroMAX pink sets: REFRES R_meas 0.0507/0.0507 (lyso),
0.0842/0.0844 (thau), REFRES ISa 28.83/28.77, 14.12/14.12 - no bandwidth-specific effect.
- the "--integration-stencil has no effect without --bandwidth" message, which is decided before the
pre-scan and would now be wrong.
The one set where clip 3 helps (9z44, 7 A: R_meas 0.252 -> 0.201) gains the same at zero bandwidth, so
that is a property of the clip, not of the beam.
Effect of the measured bandwidth (stencil 0, clip 4), against hq-integ 9b6736dbd at the same
resolution range (REFRES; open sets rerun with --report-resolution at the base d_min): R_meas up on
all six consumers - MicroMAX pink lyso 0.0499 -> 0.0507, thau 0.0824 -> 0.0844, 9q41 0.250 -> 0.265,
8u0i 0.0796 -> 0.0816, 9sl0 0.0758 -> 0.0773, 9z44 0.252 -> 0.255; CC1/2 unchanged to 1e-4; CC_MODEL
overall +0.001/+0.0004/+0.0005/-0.0025 (9q41/8u0i/9sl0/9z44); no space-group change.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D1G8gJVAy6gp1K5Dz3NE5C
leonarski_fandClaude Opus 5.5
1a307d9c36
