Record passing RM3 PTO extension finer-step audit

PARITY.md

@@ -58,7 +58,7 @@ the production Python code. The live wave comparison passed on 6 October
 | RM3 End_Stops force law and refined-step trajectory | Pinned MATLAB Applications `End_Stops` input; R2025b runs at published 0.1 s and diagnostic 0.025/0.0125 s steps through the published 400 s duration | Effective stroke bounds are ±0.6 m, each spring is 100 MN/m, stop damping is zero, and the 0.0001 m transition is active. The source's logged stop force matches the Python smooth-stop law within `1e-5` N even at saved samples inside the transition. The 0.025-to-0.0125 s source stroke difference is at most 2.79 mm over 400 s; the published 0.1 s run differs from the refined source by up to 286 mm after contact. The opt-in Python adaptive solver with implicit added mass agrees with the 0.0125 s MATLAB trajectory over 400 s within 0.986 mm PTO stroke, 6.77 mm/s PTO speed, 98.2 kN PTO force, and 0.139% ordinary damper energy. Paired gates cover both active body positions and velocities, PTO motion and force, and integrated energy; a separate source convergence gate checks both refined MATLAB steps. |
 | RM3 radiation force options: constant, convolution, FIR, and state-space | Pinned MATLAB Applications `Radiation_Force_Options`, BEMIO-generated RM3 HDF5, 12 s regular waves | All four published 500 s settings are checked against the Python floating-joint solver. The FIR path uses sampled kernel taps with a held radiation force during each RK4 step. Across all four cases, the largest differences are 30.7 mm surge, 2.11 mm heave, 0.00144 rad pitch, 3.25 mm PTO stroke, 1.55 mm/s PTO speed, 1.86 kN PTO force, and 1.57 kW PTO power. Direct FIR radiation-force differences remain under their paired gates. MATLAB FIR differs from MATLAB convolution by up to 345 mm surge, so the methods are not interchangeable for this case. The opt-in `radiation_method="state_space"` advances its 72 active fitted states with the independent RM3 body motion and passes the same full-duration gates; its force law on prescribed source motion is checked separately below. The fitted model has negative low-frequency damping, so this is numerical source parity, not physical passivity evidence. |
 | RM3 state-space radiation force on prescribed motion | Pinned MATLAB Applications `Radiation_Force_Options` state-space setting and [focused R2025b gate](https://github.com/cmudrc/wec-sim-python/actions/runs/37935700135) | `wecsim.hydrodynamics.radiation.replay_rm3_fitted_radiation` advances the HDF5 A/B/C channel fits from zero state using the saved six-component velocity histories, scales C by water density, and sets D to zero as the pinned MATLAB block does. Over 5,001 samples on both bodies, every radiation-force channel differs by less than `0.026%` of its source peak; the gate allows `0.03%` with a `0.0009` N floor for nearly stationary channels. This is a prescribed-motion force replay, not an independently coupled trajectory or evidence that the fitted model is passive. The default convolution solver is unchanged. |
-| RM3 PTO extension float and spar free decays | Pinned MATLAB Applications `RM3_PTO_Extension` inputs and BEMIO-generated RM3 HDF5; [three-step R2025b audit](https://github.com/cmudrc/wec-sim-python/actions/runs/38130573831) | The no-wave floating-joint solver initializes the float at +5 m or the spar at −5 m, reproducing each published case's +5 m PTO stroke. At the published 0.1 s step, maximum 30 s active-heave differences are 47.1 mm for float and 6.84 mm for spar, with speed differences of 86.0 and 1.87 mm/s. Changing only MATLAB `simu.dt` to 0.05 and 0.025 s changes the source float heave by 53.5 then 15.8 mm and spar heave by 7.32 then 3.82 mm. At matched 0.1/0.05/0.025 s steps, independent Python float-heave errors fall 47.1/22.8/11.4 mm and spar-heave errors 6.84/3.43/1.72 mm. The finest-step speed errors are 21.4 mm/s float and 0.467 mm/s spar; focused gates allow 16/2.5 mm heave and 30/0.7 mm/s speed, respectively, and cover PTO stroke, speed, force, and power. Both source and Python show decreasing step changes through these three levels; this is numerical evidence for the pinned free-decay cases, not a proof of asymptotic convergence or a general no-wave joint solver. The passive body remains stationary within numerical precision; PTO force and power are zero in Python and below `3.5e-8` in MATLAB output. |
+| RM3 PTO extension float and spar free decays | Pinned MATLAB Applications `RM3_PTO_Extension` inputs and BEMIO-generated RM3 HDF5; [three-step R2025b audit](https://github.com/cmudrc/wec-sim-python/actions/runs/38130573831) and [passing fourth-step audit](https://github.com/cmudrc/wec-sim-python/actions/runs/38324343546) | The no-wave floating-joint solver initializes the float at +5 m or the spar at −5 m, reproducing each published case's +5 m PTO stroke. At the published 0.1 s step, maximum 30 s active-heave differences are 47.1 mm for float and 6.84 mm for spar, with speed differences of 86.0 and 1.87 mm/s. Changing only MATLAB `simu.dt` from 0.05 to 0.025 to 0.0125 s changes the source float heave by 15.81 then 8.53 mm and spar heave by 3.82 then 1.96 mm; the last changes are 54.0% and 51.2% of the previous ones. The corresponding float-speed changes are 77.96 then 39.14 mm/s, and spar-speed changes are 2.443 then 1.222 mm/s. At matched 0.025/0.0125 s steps, independent Python float-heave errors fall from 11.37 to 5.69 mm and spar-heave errors from 1.72 to 0.861 mm; speed errors fall from 21.40 to 10.69 mm/s and from 0.467 to 0.233 mm/s. The 0.0125 s gate allows 9/1.5 mm heave and 17/0.4 mm/s speed for float/spar and requires each error to fall below 75% of its 0.025 s value. PTO stroke and speed have the same errors as active heave and speed within numerical precision; PTO force and power are zero in Python and below `3.5e-8` in MATLAB output. Both CI cases pass full 30 s source self-change and independent Python motion/PTO gates. The passive body remains stationary within numerical precision. This is refined-step numerical evidence, not a passing gate for either published 0.1 s case, proof of asymptotic convergence, or a general no-wave joint solver. |
 | RM3 Multiple Condition Runs Option 1 physical sweep | Pinned MATLAB Applications RM3 input, expanded to eight scalar height × period × PTO-damping combinations | The Python `regularCIC` floating-joint solver agrees across all eight 400 s conditions within 75.1 mm surge, 0.387 mm heave, 0.000183 rad pitch, 0.413 mm PTO stroke, 0.231 mm/s PTO speed, 0.479 kN PTO force, and 0.487 kW PTO power. These scalar runs validate each physical condition; all three MCR drivers are separately checked below. |
 | RM3 Multiple Condition Runs Options 1–3 orchestration | Pinned MATLAB Applications arrays, Option 2 Excel grid, Option 3 MAT file, and three actual MATLAB R2025b `wecSimMCR` runs | The Python loaders produce the same ordered eight-case table for all three published inputs. Each driver has a separate paired gate for every body's 4,001 position and velocity samples, every PTO stroke, speed, force, and power trace, the eight mean powers, and two 2×2 power matrices with period rows and height columns. Python mean absorbed powers differ from MATLAB by at most 0.155 kW or 0.059% across eight conditions in the MAT driver. The Option 2 Excel and Option 3 MAT driver outputs agree numerically exactly; Option 1 array and Option 3 MAT body positions differ by at most `1.9e-12` m. MATLAB's PTO power sign is opposite Python's positive absorbed-power convention. Phase-seed sweeps, multiple PTOs, and other postprocessing are not yet paired. |
 | Public RM3 floating-joint configuration | Pinned MATLAB MCR Option 1 array condition 1 and published MooringMatrix application; fresh paired [MCR](https://github.com/cmudrc/wec-sim-python/actions/runs/37787926107) and [mooring](https://github.com/cmudrc/wec-sim-python/actions/runs/37787936962) runs | `WEC.floating_joint` routes a Python-configured two-body device through the already paired pitched-slider solver and returns named body, four-coordinate, and PTO histories. In the 400 s MCR case, maximum differences are 35.1 mm surge, 0.228 mm heave, `3.46e-6` rad pitch, 0.243 mm PTO stroke, 163 N PTO force, and 118 W absorbed power; explicit gates cover positions, speeds, stroke, force, and power at all 4,001 samples. A second public configuration reproduces the 400 s imported-elevation MooringMatrix run, including its initial spar offset and joint surge spring, under the existing 40,001-sample body/PTO/mooring gates. Both fresh MATLAB jobs pass. The builder's implicit added-mass default remains physical; source-compatible delayed feedback is explicit for the MCR comparison. This layout does not represent arbitrary Simscape joints or off-axis PTO endpoints. |