Where the molecular transform's FFT runs on the CPU - a CPU-only build, --no-gpu, a card too small for it -
it was one single-threaded FFTW 3D r2c: 12.5 s of 13 s of the transform on 4nwv's 768^3 box, one core busy
while fifteen waited. Now MapToFPhiInParallel does it as two passes over the threads: the r2c along w of
every (u, v) column, then the 2D transform of each plane l the search keeps (l <= reach), cropping as
CropHalfL does. Each column and each plane is done by one plan, so the result does not depend on the thread
count; it agrees with FFTW's 3D plan to float rounding, not bit for bit. The GPU path is unchanged.
CPU-only (--no-gpu), timing benchmark: 4nwv's transform 13.1 -> 2.4 s (provisional, load average 13-25).
What the rounding moved: 4nwv and myob came out byte-identical; on cytc (three copies, tNCS) the null's
replicates, placed by the translation function, read the fit at +22.8 sd instead of +18.7 (MR_HAND_FIT_SIGMA),
and the placement - same R-work, R-free and every MR candidate line - came out at an origin-equivalent
position 43 A from the previous one, so its model file and maps differ while the answer (ENANTIOMORPH,
P 32 2 1, placement CC 0.744) does not. GPU runs byte-identical on all three. [MolecularReplacement] passes.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
leonarski_fandClaude Opus 5.5
8d17d05227