Compared with ctruncate (CCP4 9, version 1.17.29) on rugnux's own merged
intensities of the open battery arm, three differences:
- ctruncate gives no amplitude to an intensity below -3.7 sigma (exactly
that bound on every set checked; up to 2498 reflections on one set).
Rugnux turned them into small, confident amplitudes (F/Fc ~0.3 on the
sets whose background is over-subtracted on powder/ice rings). They now
get F = NaN (missing in MTZ, '?' in mmCIF); IMEAN is kept. They are
also left out of the shell mean that sets the Wilson prior.
- The switch to sqrt(I) at I/sigma = 4 left 4-6 sigma amplitudes 2-3%
above ctruncate's on every set (1.019-1.028). The posterior now applies
up to 20 sigma (emulated: 0.995-1.000).
- A shell whose mean intensity is not positive gave a prior at the 1e-10
clamp and amplitudes of ~0 (one set's outer shell); it now takes the
nearest lower-resolution shell's mean.
The remaining gap (weak amplitudes 2-5% below ctruncate's in the outer
shells) is ctruncate's anisotropy-corrected prior; not attempted. An
offline R-free ablation put the whole ctruncate conversion at -0.0006
median (15/18 sets better) and dropping its rejected negatives at -0.0009
mean (-0.009 on the worst set).
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
23f446acbb
