[cmccomb]

Purpose

Run the pinned Nonlinear_Hydro/ode45/Regular application over the full 150 s with a 0.000625 s physical step and 0.005 s output sampling. Four all-clock 0.000625 s attempts, including a fresh-process attempt in #660, lost the hosted runner during simulation and produced no scientific result. This is a separate, explicitly mixed-clock source trial in cmudrc/wec-sim-python only.

Controls and limits

The script copies the published application and changes only simu.dt from 0.05 to 0.000625 s plus an explicit simu.dtOut=0.005 s. Runtime assertions require simu.dt, nonlinearDt, cicDt, and Simulink MaxStep to remain 0.000625 s; the published wave, duration, ramp, nonlinear-hydro mode, and PTO damping are pinned. It exports all 11 active-axis motion, force, power, wave, and force-law channels at 0.005 s output times, with generated BEM HDF5 and application STL for comparison.

The #659 output-grid A/B measured exact common-grid equality when dtOut changed from 0.00125 to 0.005 s while the physical clocks stayed at 0.00125 s. That establishes logging neutrality at 1.25 ms only, not at this 0.625 ms physical step. This run must still pass the predeclared four-step source contraction, source signed-work, Python motion/PTO, and 0.1% direct signed-work gates in #655 before any derived reference can be adopted. The original 0.05 s published-input gate and status remain intact. This diagnostic alone makes no badge or issue-closure claim.

Measured Regular source result

At exact head 44b0809b295e2163d433be98b246be2ebf58113d, run 40106411780 completed the 150 s source simulation and uploaded 30,001 samples. The settings file records [dt, dtOut, nonlinearDt, cicDt, MaxStep] = [0.000625, 0.005, 0.000625, 0.000625, 0.000625] s. Against #659's fresh all-clock 0.00125 s Regular source on the same 0.005 s timestamps, wave and time agree exactly; maximum final-step changes are 0.000231452 m heave, 0.000341197 m/s speed, 409.436 N PTO force, and 333.393 W absorbed power, each below #655's predeclared source limit. The finest source signed work is 20,055,975.947 J; the fresh 0.00125 s work is 20,069,978.377 J on its full grid and 20,069,980.819 J sampled at 0.005 s. The finest force and power satisfy the pinned damping law within 1.3e-9 in their units.

These are one case's final-step source measurements. Fresh corrected-axis 0.005 and 0.0025 s histories, full four-step contraction, and independent Python limits are still required before a derived-reference claim.

Independent Regular Python measurement

Against this run's generated HDF5 and STL, the public Python model advanced independently over the full 150 s at 0.0025 and 0.00125 s. Its self-step changes were 1.47e-6 m heave, 3.66e-6 m/s speed, 4.388 N PTO force, and 3.016 W absorbed power, all below the original #655 self-step limits. On the source's 0.005 s output grid, the Python/source maximum differences were 0.000231346 m heave, 0.000338943 m/s speed, 0.000231346 m PTO stroke, 406.732 N PTO force, and 328.493 W power, all below the original #655 physical limits. Signed Python work was 20,041,991.621 J against 20,055,975.947 J source work, a 0.0697265% difference below the unchanged 0.1% gate. Python full/common work sampling differed by 2.07e-8 relative. This direct measurement still does not replace the pending four-step corrected-axis source contraction.

[cmccomb]

The successful finest Regular source artifact and its checked configuration were consolidated and independently reproduced by the exact-head convergence workflow in merged #655. This diagnostic PR is superseded.