The POINTLESS-style symmetry search discarded a real point group on two
hard rotation-test crystals:
- Ins_I_3 (I23): one of the eight cubic 3-fold operators scored CC 0.483,
just under the 0.5 per-operator floor, so I23 fell to I222 and merging
collapsed (3-fold orientation ambiguity; CC1/2 1%, R-meas 558%). Gate A
now scores each CONJUGACY CLASS of a point group's rotations by its mean
CC - conjugate operators are symmetry-equivalent and must stand or fall
together - so the cubic 3-fold class (mean 0.57) is confirmed. -> I23,
CC1/2 99.9%. Degenerate (few-pair / NaN) class members are skipped
rather than vetoing the class.
- Benas_3/7 (F432): the chi^2 self-consistency gate rejected the true
cubic group because the weak-data error model is badly miscalibrated
(reduced chi^2 ~150), which inflates the chi^2 ratio with point-group
order for genuine high symmetry too. The ratio bound is now widened by
log10(chi2_ref) so a broken error model does not veto real symmetry,
while a false operator whose ratio is far worse than its subgroup's is
still caught. The bound stays a per-candidate chi^2 test - chi^2 still
arbitrates and is never bypassed. Verified: F432 (chi2_ref 151, ratio
3.2 < bound 4.2) accepted; a calibrated pseudo/twin R32 (Ins_H_3:
chi2_ref 2.6, ratio 4.2 > bound 2.4) still rejected, stays R3.
SearchSpaceGroup.{cpp,h} only. Validated on the 24-crystal rotation-test
battery: exactly these two space groups change (both now match the
reference); zero regressions - every pseudo-symmetry P1 case and every
correct assignment unchanged.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 4.8
8c288c8697