The gate for merging the space-group search's all-observation arm on a copy of the engine, beside
the first arm, judged an engine at a fixed 256 B per observation. It now counts what the ingest
knows - observations, rocking events (at most one full each) and distinct hkl (at most one ASU
group each) - at 80 / 260 / 200 B, the envelope of the measured per-engine peaks (helpers
included: error-model fit, Wilson outlier test, pair sort), plus a fifth, and keeps 3 GB of the
card for what else stays resident (context, the run's indexers: measured up to 2.3 GB at the gate
with no speculative pass running).
Measured per-engine peaks (scratch build tracking each engine's device allocations): 4nwv 7.98 GB,
8a1a 8.15, 8tyy 9.36, 8qaw 13.3 - two engines do not fit a 16 GB card on any of these, so they stay
serial. The old constant was not an over-estimate there (fulls cost ~260 B each at the surface
fit). What changes: 9 battery sets of 33-53 M observations at high multiplicity (8s38, 8sqt,
7ph1, 9min, 9i80, 9sl0, 9h0q, 8v4o, 6ze4) now merge the arm beside; none goes the other way.
Their merge-step VRAM peak is 11.0-14.1 GiB of 15.9, no out-of-memory, no failed speculative probe.
Every engine peak measured on 11 sets is at most 81% of the estimate.
Output identical (p.hkl md5 and MTZ data, 40 sets incl. ci tier). Gain is small: the two merges
share one GPU, so the arm beside slows the main P1 merge by ~0.5 s while saving ~0.7-1 s of wait
at the search; alternating A/B on 5 of the sets: -1.1 s output pass in total.
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
9d6a3f1e04