Pair OSWEC variable-hydro yaw heading bank with MATLAB

.github/workflows/reference-model-baselines.yml

@@ -84,7 +84,7 @@ on:
       model:
         description: Run all models or a selected reference application
         type: choice
-        options: [all, RM3_MCR_ARRAY, SPHERE_ELEVATION_IMPORT, MORISON_FIXED, SPHERE_MOVING_MORISON, SPHERE_MOVING_MORISON_WAVE, RM3_DD_PTO, SPHERE_MPC, GBM_BARGE, SPHERE_REACTIVE_DDPTO, SPHERE_VARIABLE_MASS, ELLIPSOID_NLH_REG, ELLIPSOID_NLH_CIC, ELLIPSOID_NLH_ODE45, OSWEC_PASSIVE_YAW_IRR_CONT, OSWEC_PASSIVE_YAW_IRR, OSWEC_PASSIVE_YAW, OSWEC_FULL_DIR, OSWEC_MULTI_WAVE, RM3_B2B, RM3_MOORING_MATRIX, SPHERE_MEAN_DRIFT, RM3_MCR_SEASTATE, RM3_END_STOPS, RM3_END_STOPS_STEP, RM3_END_STOPS_STEP_FINE, RM3_END_STOPS_STEP_FINER, RM3_END_STOPS_FULL_FINE, RM3_END_STOPS_FULL_FINER, RM3_END_STOPS_FULL_PAIR]
+        options: [all, RM3_MCR_ARRAY, SPHERE_ELEVATION_IMPORT, MORISON_FIXED, SPHERE_MOVING_MORISON, SPHERE_MOVING_MORISON_WAVE, RM3_DD_PTO, SPHERE_MPC, GBM_BARGE, SPHERE_REACTIVE_DDPTO, SPHERE_VARIABLE_MASS, ELLIPSOID_NLH_REG, ELLIPSOID_NLH_CIC, ELLIPSOID_NLH_ODE45, OSWEC_PASSIVE_YAW_IRR_CONT, OSWEC_PASSIVE_YAW_IRR, OSWEC_PASSIVE_YAW, OSWEC_VARIABLE_YAW_2DEG, OSWEC_FULL_DIR, OSWEC_MULTI_WAVE, RM3_B2B, RM3_MOORING_MATRIX, SPHERE_MEAN_DRIFT, RM3_MCR_SEASTATE, RM3_END_STOPS, RM3_END_STOPS_STEP, RM3_END_STOPS_STEP_FINE, RM3_END_STOPS_STEP_FINER, RM3_END_STOPS_FULL_FINE, RM3_END_STOPS_FULL_FINER, RM3_END_STOPS_FULL_PAIR]
         default: all
 
 jobs:
@@ -94,7 +94,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        model: ${{ fromJSON(inputs.model == 'RM3_MCR_ARRAY' && '["RM3_MCR_ARRAY"]' || inputs.model == 'SPHERE_ELEVATION_IMPORT' && '["SPHERE_ELEVATION_IMPORT"]' || inputs.model == 'MORISON_FIXED' && '["MORISON_FIXED"]' || inputs.model == 'SPHERE_MOVING_MORISON' && '["SPHERE_MOVING_MORISON"]' || inputs.model == 'SPHERE_MOVING_MORISON_WAVE' && '["SPHERE_MOVING_MORISON_WAVE"]' || inputs.model == 'RM3_DD_PTO' && '["RM3_DD_PTO"]' || inputs.model == 'SPHERE_MPC' && '["SPHERE_MPC"]' || inputs.model == 'GBM_BARGE' && '["GBM_BARGE"]' || inputs.model == 'SPHERE_REACTIVE_DDPTO' && '["SPHERE_REACTIVE_DDPTO"]' || inputs.model == 'SPHERE_VARIABLE_MASS' && '["SPHERE_VARIABLE_MASS"]' || inputs.model == 'ELLIPSOID_NLH_REG' && '["ELLIPSOID_NLH_REG"]' || inputs.model == 'ELLIPSOID_NLH_CIC' && '["ELLIPSOID_NLH_CIC"]' || inputs.model == 'ELLIPSOID_NLH_ODE45' && '["ELLIPSOID_NLH_ODE45"]' || inputs.model == 'OSWEC_PASSIVE_YAW_IRR_CONT' && '["OSWEC_PASSIVE_YAW_IRR_CONT"]' || inputs.model == 'OSWEC_PASSIVE_YAW_IRR' && '["OSWEC_PASSIVE_YAW_IRR"]' || inputs.model == 'OSWEC_PASSIVE_YAW' && '["OSWEC_PASSIVE_YAW"]' || inputs.model == 'OSWEC_FULL_DIR' && '["OSWEC_FULL_DIR"]' || inputs.model == 'OSWEC_MULTI_WAVE' && '["OSWEC_MULTI_WAVE"]' || inputs.model == 'RM3_B2B' && '["RM3_B2B"]' || inputs.model == 'RM3_MOORING_MATRIX' && '["RM3_MOORING_MATRIX"]' || inputs.model == 'SPHERE_MEAN_DRIFT' && '["SPHERE_MEAN_DRIFT"]' || inputs.model == 'RM3_MCR_SEASTATE' && '["RM3_MCR_SEASTATE"]' || inputs.model == 'RM3_END_STOPS' && '["RM3_END_STOPS"]' || inputs.model == 'RM3_END_STOPS_STEP' && '["RM3_END_STOPS_STEP"]' || inputs.model == 'RM3_END_STOPS_STEP_FINE' && '["RM3_END_STOPS_STEP_FINE"]' || inputs.model == 'RM3_END_STOPS_STEP_FINER' && '["RM3_END_STOPS_STEP_FINER"]' || inputs.model == 'RM3_END_STOPS_FULL_FINE' && '["RM3_END_STOPS_FULL_FINE"]' || inputs.model == 'RM3_END_STOPS_FULL_FINER' && '["RM3_END_STOPS_FULL_FINER"]' || inputs.model == 'RM3_END_STOPS_FULL_PAIR' && '["RM3_END_STOPS_FULL_FINE", "RM3_END_STOPS_FULL_FINER"]' || '["SPHERE_ELEVATION_IMPORT", "MORISON_FIXED", "SPHERE_MOVING_MORISON", "SPHERE_MOVING_MORISON_WAVE", "RM3_DD_PTO", "RM3", "OSWEC", "OSWEC_Nonhydro", "GBM_BARGE", "SPHERE_VARIABLE_MASS", "SPHERE_REACTIVE_DDPTO", "OSWEC_FULL_DIR", "OSWEC_MULTI_WAVE", "OSWEC_PASSIVE_YAW", "Sphere", "SPHERE_MEAN_DRIFT", "RM3_B2B", "RM3_END_STOPS", "RM3_PTO_Extension", "RM3_Radiation_Options", "Sphere_Passive", "Sphere_PTO_Config", "Sphere_Reactive_PI", "Sphere_Declutching", "Sphere_Latching", "RM3_MCR", "RM3_MCR_ARRAY", "RM3_MCR_EXCEL", "RM3_MCR_MAT", "RM3_MCR_SEASTATE", "ELLIPSOID_NLH_REG", "ELLIPSOID_NLH_CIC", "ELLIPSOID_NLH_ODE45"]') }}
+        model: ${{ fromJSON(inputs.model == 'RM3_MCR_ARRAY' && '["RM3_MCR_ARRAY"]' || inputs.model == 'SPHERE_ELEVATION_IMPORT' && '["SPHERE_ELEVATION_IMPORT"]' || inputs.model == 'MORISON_FIXED' && '["MORISON_FIXED"]' || inputs.model == 'SPHERE_MOVING_MORISON' && '["SPHERE_MOVING_MORISON"]' || inputs.model == 'SPHERE_MOVING_MORISON_WAVE' && '["SPHERE_MOVING_MORISON_WAVE"]' || inputs.model == 'RM3_DD_PTO' && '["RM3_DD_PTO"]' || inputs.model == 'SPHERE_MPC' && '["SPHERE_MPC"]' || inputs.model == 'GBM_BARGE' && '["GBM_BARGE"]' || inputs.model == 'SPHERE_REACTIVE_DDPTO' && '["SPHERE_REACTIVE_DDPTO"]' || inputs.model == 'SPHERE_VARIABLE_MASS' && '["SPHERE_VARIABLE_MASS"]' || inputs.model == 'ELLIPSOID_NLH_REG' && '["ELLIPSOID_NLH_REG"]' || inputs.model == 'ELLIPSOID_NLH_CIC' && '["ELLIPSOID_NLH_CIC"]' || inputs.model == 'ELLIPSOID_NLH_ODE45' && '["ELLIPSOID_NLH_ODE45"]' || inputs.model == 'OSWEC_PASSIVE_YAW_IRR_CONT' && '["OSWEC_PASSIVE_YAW_IRR_CONT"]' || inputs.model == 'OSWEC_PASSIVE_YAW_IRR' && '["OSWEC_PASSIVE_YAW_IRR"]' || inputs.model == 'OSWEC_PASSIVE_YAW' && '["OSWEC_PASSIVE_YAW"]' || inputs.model == 'OSWEC_VARIABLE_YAW_2DEG' && '["OSWEC_VARIABLE_YAW_2DEG"]' || inputs.model == 'OSWEC_FULL_DIR' && '["OSWEC_FULL_DIR"]' || inputs.model == 'OSWEC_MULTI_WAVE' && '["OSWEC_MULTI_WAVE"]' || inputs.model == 'RM3_B2B' && '["RM3_B2B"]' || inputs.model == 'RM3_MOORING_MATRIX' && '["RM3_MOORING_MATRIX"]' || inputs.model == 'SPHERE_MEAN_DRIFT' && '["SPHERE_MEAN_DRIFT"]' || inputs.model == 'RM3_MCR_SEASTATE' && '["RM3_MCR_SEASTATE"]' || inputs.model == 'RM3_END_STOPS' && '["RM3_END_STOPS"]' || inputs.model == 'RM3_END_STOPS_STEP' && '["RM3_END_STOPS_STEP"]' || inputs.model == 'RM3_END_STOPS_STEP_FINE' && '["RM3_END_STOPS_STEP_FINE"]' || inputs.model == 'RM3_END_STOPS_STEP_FINER' && '["RM3_END_STOPS_STEP_FINER"]' || inputs.model == 'RM3_END_STOPS_FULL_FINE' && '["RM3_END_STOPS_FULL_FINE"]' || inputs.model == 'RM3_END_STOPS_FULL_FINER' && '["RM3_END_STOPS_FULL_FINER"]' || inputs.model == 'RM3_END_STOPS_FULL_PAIR' && '["RM3_END_STOPS_FULL_FINE", "RM3_END_STOPS_FULL_FINER"]' || '["SPHERE_ELEVATION_IMPORT", "MORISON_FIXED", "SPHERE_MOVING_MORISON", "SPHERE_MOVING_MORISON_WAVE", "RM3_DD_PTO", "RM3", "OSWEC", "OSWEC_Nonhydro", "GBM_BARGE", "SPHERE_VARIABLE_MASS", "SPHERE_REACTIVE_DDPTO", "OSWEC_FULL_DIR", "OSWEC_MULTI_WAVE", "OSWEC_PASSIVE_YAW", "Sphere", "SPHERE_MEAN_DRIFT", "RM3_B2B", "RM3_END_STOPS", "RM3_PTO_Extension", "RM3_Radiation_Options", "Sphere_Passive", "Sphere_PTO_Config", "Sphere_Reactive_PI", "Sphere_Declutching", "Sphere_Latching", "RM3_MCR", "RM3_MCR_ARRAY", "RM3_MCR_EXCEL", "RM3_MCR_MAT", "RM3_MCR_SEASTATE", "ELLIPSOID_NLH_REG", "ELLIPSOID_NLH_CIC", "ELLIPSOID_NLH_ODE45"]') }}
     name: ${{ matrix.model }}
     steps:
       - uses: actions/checkout@v7
@@ -108,7 +108,7 @@ jobs:
             source
             examples/${{ matrix.model }}
       - uses: actions/checkout@v7
-        if: matrix.model == 'SPHERE_ELEVATION_IMPORT' || matrix.model == 'MORISON_FIXED' || matrix.model == 'SPHERE_MOVING_MORISON' || matrix.model == 'SPHERE_MOVING_MORISON_WAVE' || matrix.model == 'RM3_DD_PTO' || matrix.model == 'SPHERE_MPC' || matrix.model == 'GBM_BARGE' || matrix.model == 'SPHERE_REACTIVE_DDPTO' || matrix.model == 'SPHERE_VARIABLE_MASS' || matrix.model == 'ELLIPSOID_NLH_REG' || matrix.model == 'ELLIPSOID_NLH_CIC' || matrix.model == 'ELLIPSOID_NLH_ODE45' || matrix.model == 'Sphere' || matrix.model == 'SPHERE_MEAN_DRIFT' || matrix.model == 'Sphere_Passive' || matrix.model == 'Sphere_PTO_Config' || matrix.model == 'Sphere_Reactive_PI' || matrix.model == 'Sphere_Declutching' || matrix.model == 'Sphere_Latching' || matrix.model == 'RM3_B2B' || matrix.model == 'RM3_MOORING_MATRIX' || matrix.model == 'RM3_END_STOPS' || matrix.model == 'RM3_END_STOPS_STEP' || matrix.model == 'RM3_END_STOPS_STEP_FINE' || matrix.model == 'RM3_END_STOPS_FULL_FINE' || matrix.model == 'RM3_END_STOPS_FULL_FINER' || matrix.model == 'RM3_END_STOPS_STEP_FINER' || matrix.model == 'RM3_PTO_Extension' || matrix.model == 'RM3_Radiation_Options' || matrix.model == 'RM3_MCR' || matrix.model == 'RM3_MCR_ARRAY' || matrix.model == 'RM3_MCR_EXCEL' || matrix.model == 'RM3_MCR_MAT' || matrix.model == 'RM3_MCR_SEASTATE' || matrix.model == 'OSWEC_Nonhydro' || matrix.model == 'OSWEC_MULTI_WAVE' || matrix.model == 'OSWEC_FULL_DIR' || matrix.model == 'OSWEC_PASSIVE_YAW' || matrix.model == 'OSWEC_PASSIVE_YAW_IRR' || matrix.model == 'OSWEC_PASSIVE_YAW_IRR_CONT'
+        if: matrix.model == 'SPHERE_ELEVATION_IMPORT' || matrix.model == 'MORISON_FIXED' || matrix.model == 'SPHERE_MOVING_MORISON' || matrix.model == 'SPHERE_MOVING_MORISON_WAVE' || matrix.model == 'RM3_DD_PTO' || matrix.model == 'SPHERE_MPC' || matrix.model == 'GBM_BARGE' || matrix.model == 'SPHERE_REACTIVE_DDPTO' || matrix.model == 'SPHERE_VARIABLE_MASS' || matrix.model == 'ELLIPSOID_NLH_REG' || matrix.model == 'ELLIPSOID_NLH_CIC' || matrix.model == 'ELLIPSOID_NLH_ODE45' || matrix.model == 'Sphere' || matrix.model == 'SPHERE_MEAN_DRIFT' || matrix.model == 'Sphere_Passive' || matrix.model == 'Sphere_PTO_Config' || matrix.model == 'Sphere_Reactive_PI' || matrix.model == 'Sphere_Declutching' || matrix.model == 'Sphere_Latching' || matrix.model == 'RM3_B2B' || matrix.model == 'RM3_MOORING_MATRIX' || matrix.model == 'RM3_END_STOPS' || matrix.model == 'RM3_END_STOPS_STEP' || matrix.model == 'RM3_END_STOPS_STEP_FINE' || matrix.model == 'RM3_END_STOPS_FULL_FINE' || matrix.model == 'RM3_END_STOPS_FULL_FINER' || matrix.model == 'RM3_END_STOPS_STEP_FINER' || matrix.model == 'RM3_PTO_Extension' || matrix.model == 'RM3_Radiation_Options' || matrix.model == 'RM3_MCR' || matrix.model == 'RM3_MCR_ARRAY' || matrix.model == 'RM3_MCR_EXCEL' || matrix.model == 'RM3_MCR_MAT' || matrix.model == 'RM3_MCR_SEASTATE' || matrix.model == 'OSWEC_Nonhydro' || matrix.model == 'OSWEC_MULTI_WAVE' || matrix.model == 'OSWEC_FULL_DIR' || matrix.model == 'OSWEC_PASSIVE_YAW' || matrix.model == 'OSWEC_VARIABLE_YAW_2DEG' || matrix.model == 'OSWEC_PASSIVE_YAW_IRR' || matrix.model == 'OSWEC_PASSIVE_YAW_IRR_CONT'
         with:
           repository: WEC-Sim/WEC-Sim_Applications
           ref: d53d4d4c9eda2581f04204f5d394a6ef84bb099e
@@ -128,6 +128,7 @@ jobs:
             Passive_Yaw/PassiveYawOFF
             Passive_Yaw/PassiveYawON
             Passive_Yaw/PassiveYawRegression
+            Variable_Hydro/Passive_Yaw
             Body-to-Body_Interactions/B2B_Case1
             Body-to-Body_Interactions/B2B_Case2
             Body-to-Body_Interactions/B2B_Case3
@@ -402,6 +403,11 @@ jobs:
         env:
           WEC_SIM_SPHERE_H5: applications/_Common_Input_Files/Sphere/hydroData/sphere.h5
           WEC_SIM_MATLAB_MODEL_OUTPUT_DIR: matlab-reference-model-output
+      - run: python -m pytest -q -s tests/test_variable_yaw_heading_bank.py
+        if: matrix.model == 'OSWEC_VARIABLE_YAW_2DEG'
+        env:
+          WEC_SIM_APPLICATIONS_DIR: applications
+          WEC_SIM_MATLAB_MODEL_OUTPUT_DIR: matlab-reference-model-output
       - run: python -m pytest -q tests/test_sphere_pto_config_parity.py
         if: matrix.model == 'Sphere_PTO_Config'
         env:

PARITY.md

@@ -57,6 +57,7 @@ the production Python code. The live wave comparison passed on 6 October
 | OSWEC `Multiple_Wave_Spectra` with two independent PM seas | Pinned MATLAB Applications `Multiple_Wave_Spectra` input and BEMIO-generated OSWEC HDF5 | The public `run_case` interface sums separate 2 m, 0° and 1 m, 90° seas with saved independent phase realizations over 100 s. Combined elevation agrees within `1e-11` m and both bodies' six excitation-force components within `1e-6` N or N m. The fixed hydrodynamic base remains stationary. With the ordinary implicit added-mass default, maximum flap differences are 106 mm surge, 10.8 mm heave, and 0.0213 rad pitch; PTO torque differs by at most 7.25 kN m. The explicit source-delay comparison reduces these to 10.3 mm, 1.20 mm, 0.00207 rad, and 818 N m. Both dynamics paths have separate paired gates. The source enables passive-yaw preprocessing, but its hinge has zero yaw motion; the source's spline frequency interpolation is selected explicitly for this case. Moving-yaw dynamics and fixed-base reactions remain unsupported. |
 | OSWEC `Full_Directional_Waves` imported spectrum | Pinned MATLAB Applications `Full_Directional_Waves` input and BEMIO-generated OSWEC HDF5 | The imported 47-frequency, 180-heading spectrum and realized phases reproduce all 8,001 wave-elevation samples within `9e-14` m. The source force block omits heading-bin width although its wave-elevation block includes it: logged excitation is about `1/sqrt(2° in radians) = 5.352` times the physically integrated force. Python keeps heading integration as its default. Explicit `matlab_omitted` quadrature plus `spline_frequency` interpolation matches all six logged excitation components for both bodies within `4e-7` N or N m. With that source forcing and ordinary implicit added mass, the 400 s flap differs by at most 12.8 mm surge, 3.52 mm heave, 0.00258 rad pitch, and 56.6 N m PTO torque. The separate opt-in Simulink-delay comparison reduces these to 1.53 mm, 0.293 mm, 0.000306 rad, and 5.54 N m. Source-compatible agreement does not establish that the omitted-width force is physically correct. The fixed base remains stationary; its ground reactions are not computed. |
 | OSWEC passive yaw off and on | Pinned MATLAB Applications `PassiveYawOFF` and `PassiveYawON` inputs, BEMIO-generated OSWEC HDF5, and fresh R2025b trajectories | The public `WEC` interface defines a yawing flap, fixed hydrodynamic base, and 120,000 N m s/rad rotational PTO. Both published 600 s cases use 2.5 m, 8 s waves at 10°. With passive yaw off, Python and MATLAB flap yaw agree within `4e-14` rad. With passive yaw on, excitation follows the body-relative wave heading and turns the flap toward the 10° incident heading; yaw and angular-speed differences stay below 0.00149 rad and 0.000193 rad/s. PTO torque and absorbed power differ by at most 23.2 N m and 0.128 W, accounting for MATLAB's negative absorbed-power sign. On the saved MATLAB yaw trajectory, all six reconstructed excitation components differ by at most 100 N or N m except yaw moment, which differs by 467 N m. The source holds heading coefficients until yaw changes by 0.01°, while Python interpolates continuously. The fixed base is stationary; full three-dimensional joint mechanics remain unsupported. |
+| OSWEC variable-hydrodynamics passive yaw, 2° bank | Pinned MATLAB Applications `Variable_Hydro/Passive_Yaw` with its published regular-wave, 600 s, 0.01 s case and the first published `-40:2:40` direction bank; fresh R2025b [paired run](https://github.com/cmudrc/wec-sim-python/actions/runs/37792909630) | The Python `WEC.body(..., passive_yaw=True, yaw_heading_bank=range(-40, 41, 2))` selects the nearest body-relative BEM heading using the source rule. The selected heading matches MATLAB at all 60,001 saved MATLAB states; yaw excitation evaluated on that path differs by at most 867 N m. Before the first heading-event split at 64.57 s, yaw, yaw speed, and PTO torque differ by at most `3.89e-5` rad, `3.32e-5` rad/s, and 3.98 N m. At 64.57 s the paths differ by only `3.7e-5` rad but select different headings for one sample. Discrete events amplify that offset; over the full run the maximum yaw, speed, and PTO torque differences are 0.164 rad, 0.0221 rad/s, and 2.65 kN m. Full-trajectory parity is **unestablished**. This mode covers the published pure-yaw/fixed-base regular-wave bank, not general variable hydrodynamics. |
 | OSWEC irregular passive yaw | Pinned MATLAB Applications `PassiveYawRegression` input, BEMIO-generated OSWEC HDF5, and fresh R2025b trajectory | The public `PMWave` replays the published 500-frequency phase realization over 250 s with 40 s radiation memory. Frequency bins, spectral amplitudes, and widths agree within `6e-15`; elevation agrees within `1e-13` m. The public `passive_yaw_threshold=1` selects the published coefficient hold and nearby BEM-heading snap. On MATLAB's saved yaw path, that opt-in force law matches all six logged excitation components within `1e-7` N or N m. The source's yaw radiation convolution reconstructs from its saved speed and pinned HDF5 within `5.4e-9` N m; added mass, hydrodynamic force balance, and rigid inertia balance close within `1.4e-8` N m. In a native Python run a heading update occurs one 0.01 s sample early at 53.45 s: MATLAB's relative heading is 10.99980° and Python's is 11.00004°, on opposite sides of the 11° update boundary. The yaw difference there is `4.3e-6` rad, and replaying MATLAB's logged force produces nearly the same pre-event drift (`4.29e-6` rad). Later event differences accumulate to 0.203 rad maximum yaw and 0.0277 rad/s speed differences over 250 s. With continuous heading interpolation, Python differs from the published trajectory by up to 0.452 rad yaw and 0.101 rad/s yaw speed. Replaying MATLAB's logged six-component force through the Python dynamics reduces these maximum differences to 0.00180 rad and 0.0000935 rad/s. The source force laws and balances are paired, but published-case trajectory parity with native excitation remains **unestablished** because the threshold amplifies small integration differences. |
 | OSWEC irregular passive yaw, continuous-heading control | Same pinned MATLAB input and phase realization, with only `body(1:2).yaw.threshold` changed from 1° to 0° in a temporary application copy | MATLAB and Python then agree over all 25,001 time samples: maximum differences are `1.1e-7` N or N m across the six excitation components on the MATLAB yaw path, `3.16e-5` rad flap/PTO angle, `7.30e-6` rad/s yaw/PTO speed, `0.875` N m PTO torque, and `0.0123` W source-signed power. Wave elevation differs by less than `1e-13` m and the fixed base remains stationary. This control validates the continuous-heading Python dynamics; it does not erase the published 1° threshold difference. |
 | OSWEC fixed nonhydrodynamic base | Pinned MATLAB Applications `Nonhydro_Body` case and its BEMIO-generated OSWEC HDF5 | The regular-wave solver reports the stationary base and nonlinear flap motion about the PTO hinge. Against a fresh 400 s MATLAB R2025b run (4,001 samples), maximum flap position differences are 20.8 mm surge, 7.9 mm heave, and 0.00444 rad pitch; velocity differences are 15.6 mm/s surge, 6.8 mm/s heave, and 0.00328 rad/s pitch. All six excitation-force components differ by less than 1 N, the base position and velocity agree exactly, and zero PTO torque differs only by MATLAB numerical noise below `3.3e-7` N m. The base's ground-constraint reaction forces are not calculated. |

README.md

@@ -207,6 +207,13 @@ keeps continuous interpolation. The sampled setting is available for PM waves
 with one incident direction; small trajectory differences can change its
 update sample and accumulate over long runs.
 
+For the published `Variable_Hydro/Passive_Yaw` regular-wave case, pass
+`yaw_heading_bank=range(-40, 41, 2)` alongside `passive_yaw=True` on the
+flap. This chooses the nearest 2° BEM heading from the wave direction relative
+to yaw. The source-path force and heading selection are paired to MATLAB;
+the long trajectory remains sensitive to one-sample heading changes (see
+[`PARITY.md`](PARITY.md)).
+
 The published `Morison_Element/morisonElement` application has a fixed
 monopile and tower without HDF5 hydrodynamic bodies. Its nonlinear drag and
 fluid-inertia force can be configured with a body-local point: