On rotation data the signal radius is now r1 = clamp(round(2*r80), 4, 6),
where r80 is the 80% encircled-flux radius of the crystal's own spots. The
background ring keeps its area (r3 = sqrt(r2^2 + 133)), so r1 = 4 is the
shipped default bit for bit and 26 of the 38 battery crystals come out
byte-identical.
The width had to be measured somewhere new. rugnux already has one -
shell_sigma2[].tan - but it is a second moment taken inside the r1 disk it
would be setting, and it saturates at r1/2, so feeding it back measures the
cap and not the crystal. SpotWidth instead measures encircled flux over an
aperture fixed for the whole file (14 px, normalised at 8), in the pre-scan,
from spots the finder already produces on the frames the beam-stop projection
already reads. It touches no integrator output and runs before the first
integration pass, so there is no loop, it costs no extra frame reads, and
both passes - including the space-group search, which runs in pass 1 - see
the same radius. A default run pays a median 1.9 s.
k = 2 is not fitted. For a Gaussian r80 = 1.794 sigma, so r1 = 2*r80 is
3.59 sigma, where the truncated second moment recovers 0.990 of sigma^2. The
new test checks the estimator returns 1.794 sigma on a known Gaussian.
Battery, 38 crystals, both arms run twice: the space group is identical on
all 38 and 35 agree with the reference in both arms. Per shell on the 12
crystals the rule moves, 6 win and 4 tie, with mean per-shell <I/sigma> up
30.6, 24.6, 15.8, 9.1, 8.0 and 5.1 per cent and R_meas down as much as 23.8.
Runtime is neutral - 19m13s against 22m00s warm.
One crystal is a real cost and is named in docs/RUGNUX.md with its
workaround: an I222 case that is simultaneously the widest-spot and among the
highest-mosaicity in the set loses 28.5% of its observations at unchanged
completeness, because at r1 = 6 its predicted reflection density leaves the
background ring too few clean pixels. No cheap guard separates it - its
predicted spacing is mid-table, larger than five crystals that survive r1 =
12 - and the guard that would, on the measured drop rate out of pass 1, needs
a diagnostic channel out of both integration engines and is not yet
validated.
This depends on 3ea120677: at the previous twin-law bound of 1.70 the
wider radius costs one crystal its 422, refused on an H ratio of 1.73 even
though every operator correlation confirms the point group.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CHMmeM1d489zvNFT7ZMN2P
leonarski_fandClaude Opus 5
48008e1447