The L-test now divides each intensity by its resolution-shell mean before
forming pairs, over the shells whose <I/sigma> reaches 1 (the floor the
second moment already used). Two index steps are not the same resolution,
and on a small cell with a steep fall-off the raw pairs read <|L|> up to
0.08 high: an untwinned crystal 0.568 and a partial twin 0.427 where
phenix.xtriage reads 0.486 and 0.360. Normalised, the four reference merges
(6toc, 6iu9, 5j23, a lysozyme) agree with xtriage within 0.02 (0.487,
0.376, 0.374, 0.480). Selection stays by shell, never by the reflection's
own I/sigma, which biases <|L|> down. Equal-count shells were tried for
the second moment and widen its gap to xtriage, so the shells are kept.
The L-test is no longer switched off in holohedral Laue classes. Merging
I(h) with I(Th) under a false operator gives (I(h)+I(Th))/2 for every twin
fraction, the perfect-twin distribution, so <|L|> < 0.42 there is reported
as an adopted operator averaging unequal intensities (promotion suspect, or
a twin law absorbed into the point group) - a warning, not a veto. Over 42
holohedral merges of the corpus the genuine ones read 0.436-0.513, the
over-promoted H3 twin 0.374, and one ~490 A-axis crystal 0.365.
The verdict is one line (TwinningVerdictLine) used by the stats text, the
report prose, the summary row, the warning and the viewer; a new
TWINNING_VERDICT key names it. The twin fraction comes from the statistic
that carries the verdict (the L-test unless the call rests on the second
moment alone), is not quoted from a second moment under a detected
pseudo-translation, and is not quoted at all on a merge under a suspect
operator.
The pre-search numbers (measured on the P1 search merge) are user-visible,
are measured with that merge's own pseudo-translation declared, and leave
out the reflections the lattice centring extinguishes - an R lattice in
its hexagonal cell otherwise pairs present with absent reflections (5j23:
0.633 with them, 0.40 without).
Report-only: no space-group decision, merge or intensity changes.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 5
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