jungfrauandClaude Opus 5
057fff98b2
The de-novo indexer projects every spot onto each of 16384 search directions and bins the projections; the peak of each direction's spectrum is a reciprocal lattice row spacing. One thread owned a whole direction, so neighbouring lanes wrote 12.6 kB apart and every warp instruction touched 32 separate sectors of a 206 MB buffer with no chance of staying in a 4 MB L2. 160 million scattered global read-modify-writes, at about 14% of the card's bandwidth. One block per direction now, with the bins in shared memory. They are counts, so they are held as integers: an integer atomicAdd is a real shared-memory instruction where the float one compiles to a compare-and-swap retry loop, and a count below 2^24 converts to float exactly, so the output is bit for bit what the repeated += 1.0 produced. Above 48 kB of bins the old kernel still runs. 245.75 ms per launch -> 4.08 ms, so 0.98 s of the run -> 0.016 s. This machine runs two of them at once on two cards, so it is worth about half a second here and about a second on the single-GPU machines the viewer and the broker run on. The FFT it feeds takes 3.3 ms; preparing its input took 70x longer than transforming it. Alongside it, the per-frame scale fit divided by k^2 once per observation per IRLS iteration, and a loop-invariant divisor does not get hoisted out of a double division - ptxas emits the whole Newton refinement of the reciprocal every time. Hoisted, as 1/sigma already is a few lines above; the same expression in the three CPU scale paths went with it so the two stay algebraically identical. 54.92 ms per launch -> 44.56 ms, 1.65 s -> 1.34 s. That one is not bit-identical - a multiply by a rounded reciprocal differs from a correctly rounded quotient in the last place - so it can move a frame that sits on the convergence tolerance. Battery: 21/24 space groups, no failures, and 17 of 24 crystals identical to the previous run, against a floor of 13 of 24 for the same binary run twice. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Jungfraujoch
Application to receive data from the PSI JUNGFRAU and EIGER detectors.
All documentation is now placed in docs/ subdirectory and for the current version hosted on Jungfraujoch Read The Docs page.