abb94ca450b38850da01f2af5b650cd736df632d
The per-ring sums were floats reduced by atomics, so the ring sigma - and with it the detection threshold - depended on the order the blocks happened to arrive in. Detection compares an INTEGER pixel value against that threshold, so a threshold that drifts across an integer flips every pixel of that value in the ring at once, which is how a last-bit difference turned into a different spot list. A preprocessed pixel is an exact int32 and the masked and saturated sentinels are skipped, so v and v*v are exact in 64 bits, and integer addition is associative: the sums no longer care about arrival order. Both engines now accumulate the same way, so they agree exactly rather than approximately, and the GPU spot list is bit-identical across runs. The corrected sums that feed the reported azimuthal profile stay float - a pixel value times a float correction has no exact integer form - but they do not enter the detection decision. Cost: the ring reduction needs 28 bytes per bin instead of 20 in the plain pass, which drops it from eight co-resident blocks per SM to seven and costs about 11% of that kernel (0.582 -> 0.650 ms/frame on a 4.5 Mpx frame). End to end it does not show: alternating runs on three rotation crystals came out the same or slightly faster, and the battery is unchanged in every number. The CPU engine got 30% faster (32.2 -> 22.6 ms/frame), integers being cheaper than doubles. Tests: exact CPU/GPU agreement on the spot list, and 50 repeats of bit-identical output where there were four. Co-Authored-By: Claude Opus 5 (1M context) <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.
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