Summarise a PECLET_FLOW_MG_DEBUG=2 residual trace: per solve, the iteration count, the minimum
r/r0 reached (the ATTAINABLE FLOOR when the run is driven with an unreachable rtol), the final
r/r0, and the rebound factor final/min.
The distinction this exists for: an iteration count cannot tell a FLOOR (min == final, both far
above rtol — round-off has taken over) from a REBOUND (final > min — the CG recurrence has lost
conjugacy and is walking back up) from honest slow convergence. WO-M's whole float-vs-double
comparison turns on it, and so does reading the classical attainable-accuracy bound
||r||/||r0|| ~ O(eps * kappa(A)) off a measured plateau.
Usage: <run emitting [mg] lines> | python mg_trace_parse.py [label]
1.9.8