Convenience class to generate charge perturbations following model by Nedeljkovic Soref Mashanovich

Author: marc-flex

tests/test_components/test_parameter_perturbation.py

@@ -653,3 +653,24 @@ def test_index_perturbation():
             ),
             freq=freq0,
         )
+
+
+def test_delta_model():
+    """Test delta models."""
+
+    # let's first define a frequency
+    wvl = (3.5 + 4) / 2
+    freq = td.C_0 / wvl
+    delta_model = td.NedeljkovicSorefMashanovich(ref_freq=freq)
+
+    # make sure it's interpolating correctly
+    coeffs_3_5 = np.array([3.10e-21, 1.210, 6.05e-20, 1.145, 6.95e-21, 0.986, 9.28e-18, 0.834])
+    coeffs_4 = np.array([7.4e-22, 1.245, 5.43e-20, 1.153, 7.25e-21, 0.991, 9.99e-18, 0.839])
+
+    averaged_vals = (coeffs_3_5 + coeffs_4) / 2
+    interpolated_results = [
+        value.item() for _, value in delta_model._coeffs_at_ref_freq.data_vars.items()
+    ]
+    error = np.abs(np.mean(averaged_vals - np.array(interpolated_results)))
+
+    assert error < 1e-16

tidy3d/__init__.py

@@ -290,6 +290,7 @@
     IndexPerturbation,
     LinearChargePerturbation,
     LinearHeatPerturbation,
+    NedeljkovicSorefMashanovich,
     ParameterPerturbation,
     PermittivityPerturbation,
 )
@@ -432,6 +433,7 @@ def set_logging_level(level: str) -> None:
     "RotationAroundAxis",
     "PerturbationMedium",
     "PerturbationPoleResidue",
+    "NedeljkovicSorefMashanovich",
     "ParameterPerturbation",
     "LinearHeatPerturbation",
     "CustomHeatPerturbation",