Two places where the absence tests threw away information they already had.
The screw evidence was POOLED across axial rows, so one unmeasured row vetoed a confirmed one. A
crystal reading h: +18/+24 and k: -6/+8 answered a silent P222 rather than "2_1 along a confirmed, b
undetermined". Scoring each zone separately, and letting a zone abstain, is what POINTLESS has always
done; the conditions are independent, so their log-likelihoods add.
Centring was decided on a COUNT of net absences while screws used a Beta-tail likelihood. On one
crystal that made F222 (1662 absent, 356 violations, absent class at 34% of present) beat C222_1
(1098 absent, 15 violations, 0.4%) purely because 1306 > 1083. Giving centring the same likelihood
separates them by 1717 nats - F222 -357.9, C222_1 +1359.3, I222 -787.6 - and needs no bound:
min_absent_observed and max_absent_present_ratio are untouched, and nothing was tuned to this case.
The deposited structure for that crystal is C222_1.
Corpus of 94 datasets, both arms at -N 6: 78 comparable, 73 bit-identical, point group correct on 68
against 66, space-group number on 54 against 51, nothing regressed. The 73 bit-identical results are
also the determinism control - two binaries cannot agree byte-for-byte that often by chance.
An earlier ranking key summed each group's single gating number and demoted a P2_12_12_1 to P2_12_12,
because pooling three genuine screws reads weaker than two when the third row is shallower. Summing
the per-zone log-likelihoods is what fixes that, and the whole corpus was re-run on the corrected
binary.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Lc5JG6kJqZoCWaoZ43JGTW
leonarski_fandClaude Opus 5
8634e9a72b