The online broker cancelled a collection with "Crystal lattice is coplanar and has no reciprocal
cell". The candidate filter in PostIndexingRefinement (used by FFT, FFTW and ffbidx) tests lengths,
angles and spot count only; three rows 120 deg apart in one plane pass all of them, and spots along
the plane normal index as (0,0,0). Such a candidate - from ffbidx, or one the least-squares
refinement walked flat - went on to LatticeSearch and XtalOptimizer, which refuses it and leaves it
in place, and then reached Astar() in AnalyzeIndexing/prediction, which throws; the receiver turns
that into a cancelled acquisition.
- Refine() rejects a candidate below MIN_BASIS_VOLUME_FRACTION, like any other bad candidate.
- XtalOptimizerInternal builds the refined lattice first and counts a coplanar result as a failed
refinement, writing nothing back (the residual's volume clamp lets a solve end there and report
success).
Test: PostIndexingRefinement_CoplanarCandidateIsRejected threw the exact message before the fix.
rugnux p.mtz unchanged on the three in-house reference sets at --prepass-fraction 1.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SVmAWnzCmRKAXVUCdc4iNi