Every merge downloaded the fulls' frame and group keys and built both CSRs by serial counting
sorts on the host - four passes over the fulls, two of them scattering into an array as long
as the distinct hkl (15 M on 4nwv) - and uploaded them again. They are now stable radix sorts
of the resident fulls on the card, with the counts summed there; the host gets the counts per
frame and the group CSR it walks itself. The same permutations (stable sorts list each frame's
and each group's fulls in index order, as the counting sorts did): p.hkl identical on cytc
and 4nwv.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EizBKhTqrAYago9KJG3dA3
leonarski_fandClaude Opus 5.5
eb7a65d051