The per-direction peak search starts at the 10 A floor, so a lattice row shorter than that was
reported at a multiple of itself past it and the cell built from such rows was an exact integer
supercell. A second first-pass hypothesis at a 5 A floor (the short-axis pass) won the true cell
back on frame counts, and could not reach an axis below 5 A at all.
On rotation data (a scanning axis) every shortlisted row reported within three times the floor is
now asked, by a direct sum over the accumulated spots, at each whole fraction of its length down
to 3 A; the shortest fraction that keeps half the row's amplitude replaces it. The cells of those
rows are reduced (widened: a small cell's in-plane combinations fill the standard window) and
refined beside the standard cells, and ranked with them, so where a cell and its supercell index
alike the smaller one is taken. Protein shortlists have no rows that short, so nothing changes for
them; stills and grid scans keep the search they had. The short-axis pass, its speculative pool and
its live warm-up are removed; the refined-length bound of the cell fit goes from 5 to 2.5 A.
The 40 % overlap test of the candidate refinement no longer deletes a cell for its overlap with an
integer multiple or sub-cell of it - one lattice contains the other, so that overlap is total by
construction. Such candidates are kept after every cell the test accepts, which keep their order,
so the first lattice and the extra crystals are what they were. The rotation indexer carries the
refined integer supercells of the cell it chooses, and the twin-composite test asks them as well as
the standing cell: once the search offers a twin domain's own cell, the coincidence lattice it used
to stand on is one of those.
Measured (battery subsets vs rc181-b2): a small-molecule crystal with an axis under 5 A, indexed as an
index-5 supercell now gives its true cell and group; the 13 sets the short-axis pass rescued keep
their verdicts; the sparse reticular twin keeps its domain and overlap.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UqXYdL4qBGYRiSXSGXfCLu
leonarski_fandClaude Opus 5.5
9b4acd6ab4