On a deflated Cheetah CXI with a per-frame mask (AGIPD 1M), half of the reader's time after the inflate
went to turning the stored frame into the image: the mask plane widened into a zeroed uint32 copy before
being tested, MarkBad testing it with a branch per pixel through a reference the store could alias, and
the photon conversion calling lroundf and branching on the mask, the finiteness and the clamp. Now the
mask is tested as stored (uint16 or uint32), and both loops are written so that the compiler vectorises
them: std::lround spelled out exactly (truncate, the exact fraction, a half or more away from zero) and
the selects done as arithmetic (Pick). Plain C++, no intrinsics.
Bit-identical: FNV hash of every image handed out (2000 frames) plus the pixel mask, before and after,
on a CXI with a CrystFEL geometry (with and without a gain), a panel-table HDF5 (with and without a
gain) and a bitshuffle/LZ4 int16 set: all identical. Reader alone, one thread: 14.1 -> 7.0 ms per
frame. rugnux on the 14,445-frame CXI run (16 workers, A/B back to back): geometry refinement sample
11.4 -> 8.9 s, image pass 27.6 -> 21.1 s, whole run 67.4 -> 58.2 s; geometry and refinement log lines
identical.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu
leonarski_fandClaude Opus 5.5
d345deaecd