One chain runs at a time there, after the parallel candidate solves, on 1-3.5 cores of an otherwise
idle machine. Ceres sums per-thread cost and gradient pieces, so the thread count may move a result at
rounding level; measured, it did not: identical outputs on the four reference sweeps and all 22 smoke
sets, and a sweep that indexes poorly (a chain after every spot-budget rung) went from 96 to 62 s.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01D1G8gJVAy6gp1K5Dz3NE5C
leonarski_fandClaude Opus 5.5
d71cd5b85e