When a space group is supplied without a reference cell, de-novo two-pass
rotation indexing fed the FFT's Niggli-reduced primitive cell straight into
XtalOptimizer as if it were the conventional cell. For non-primitive lattices
(centered I/F/R/C, or hexagonal where the primitive pair sits at gamma=60) the
conventional-system model then refined to a wrong minimum and indexed 0% of
frames: cytC (P3121) gave 103.9/103.9/78 instead of 83.7/83.7/88.6, insulin
(I213) 66.7 instead of 77.65, insulin-R3 51/51/36 instead of 81.4/81.4/33.3.
Run LatticeSearch on the FFT primitive cell (it already yields the correct
conventional cell + reindex for I/F/R/C). For the one remaining gap - a
metrically hexagonal lattice that the geometry-keyed search lands on the
ortho-hexagonal C setting - re-express the reduced primitive cell in
conventional hexagonal axes (b -> b - a opens gamma 60 -> 120).
De-novo "-S" now indexes cytC/insu/Ins_H/lyso/MyoB/EP/lyso_ref at 100% with the
correct cell; the "-C -S" path is unchanged. The helper stays in this .cpp
(g++) rather than CrystalLattice.h to avoid recompiling CUDA units, which is
broken under the box's CUDA-13 nvcc; promote it to a method once that is fixed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
leonarski_fandClaude Opus 4.8
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