chore: minor EME docstring and validation improvements

CHANGELOG.md

@@ -72,6 +72,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Port names in `ModalComponentModeler` and `TerminalComponentModeler` can no longer include the `@` symbol.
 - Improved speed of convolutions for large inputs.
 - Default value of `EMEModeSpec.interp_spec` is `ModeInterpSpec.cheb(num_points=3, reduce_data=True)` for faster multi-frequency EME simulations.
+- Default value of `num_sweep` in `EMECoefficientMonitor` is now `None`, recording all sweep indices.
+- Maximum number of frequencies in an `EMESimulation` is now larger if mode interpolation via `ModeInterpSpec` is used.
 
 ### Fixed
 - Ensured the legacy `Env` proxy mirrors `config.web` profile switches and preserves API URL.

schemas/EMESimulation.json

@@ -4718,7 +4718,6 @@
           "type": "integer"
         },
         "num_sweep": {
-          "default": 1,
           "minimum": 0,
           "type": "integer"
         },

tests/sims/full_fdtd.json

@@ -140,6 +140,7 @@
                 "type": "CustomMedium",
                 "interp_method": "nearest",
                 "subpixel": false,
+                "derived_from": null,
                 "eps_dataset": null,
                 "permittivity": "SpatialDataArray",
                 "conductivity": null
@@ -988,6 +989,7 @@
                 "type": "CustomMedium",
                 "interp_method": "nearest",
                 "subpixel": false,
+                "derived_from": null,
                 "eps_dataset": null,
                 "permittivity": "SpatialDataArray",
                 "conductivity": null
@@ -1032,7 +1034,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1075,7 +1078,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1117,7 +1121,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1159,7 +1164,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1200,7 +1206,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1236,6 +1243,7 @@
                 "type": "CustomMedium",
                 "interp_method": "nearest",
                 "subpixel": false,
+                "derived_from": null,
                 "eps_dataset": null,
                 "permittivity": {
                     "attrs": {},
@@ -1304,7 +1312,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1371,7 +1380,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1431,7 +1441,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1491,7 +1502,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {
@@ -1544,7 +1556,8 @@
                     ]
                 ],
                 "interp_method": "nearest",
-                "subpixel": false
+                "subpixel": false,
+                "derived_from": null
             }
         },
         {

tests/test_components/test_eme.py

@@ -419,14 +419,29 @@ def test_eme_simulation():
     with AssertLogLevel("WARNING", "slow-down"):
         sim_bad.validate_pre_upload()
 
-    sim_bad = sim.updated_copy(
+    sim_ok = sim.updated_copy(
         freqs=list(sim.freqs) + list(1e14 * np.linspace(1, 2, 1000)),
         grid_spec=sim.grid_spec.updated_copy(wavelength=1),
     )
+    sim_ok.validate_pre_upload()
+    eme_grid_spec_no_interp = td.EMECompositeGrid(
+        subgrids=[
+            s.updated_copy(interp_spec=None, path="mode_spec")
+            for s in sim_ok.eme_grid_spec.subgrids
+        ],
+        subgrid_boundaries=[-1, 1],
+    )
+    sim_bad = sim_ok.updated_copy(eme_grid_spec=eme_grid_spec_no_interp)
     with pytest.raises(SetupError):
         sim_bad.validate_pre_upload()
-    sim_bad = sim.updated_copy(
+    sim_bad = sim_ok.updated_copy(
+        freqs=list(sim.freqs) + list(1e14 * np.linspace(1, 2, 5000)),
+    )
+    with pytest.raises(SetupError):
+        sim_bad.validate_pre_upload()
+    sim_bad = sim_ok.updated_copy(
         freqs=list(sim.freqs) + list(1e14 * np.linspace(1, 2, 100)),
+        eme_grid_spec=eme_grid_spec_no_interp,
     )
     with AssertLogLevel("WARNING", contains_str="expensive"):
         sim_bad.validate_pre_upload()

tidy3d/components/eme/monitor.py

@@ -59,7 +59,7 @@ class EMEMonitor(AbstractMonitor, ABC):
     eme_cell_interval_space: Literal[1] = pd.Field(
         1,
         title="EME Cell Interval",
-        description="Number of eme cells between monitor recordings. If equal to 1, "
+        description="Number of EME cells between monitor recordings. If equal to 1, "
         "there will be no downsampling. If greater than 1, the step will be applied, but the "
         "first and last cells are always included. Not used in all monitors. "
         "Not all monitors support values different from 1.",
@@ -141,7 +141,7 @@ class EMEModeSolverMonitor(EMEMonitor):
     eme_cell_interval_space: pd.PositiveInt = pd.Field(
         1,
         title="EME Cell Interval",
-        description="Number of eme cells between monitor recordings. If equal to 1, "
+        description="Number of EME cells between monitor recordings. If equal to 1, "
         "there will be no downsampling. If greater than 1, the step will be applied, but the "
         "first and last cells are always included. Not used in all monitors. "
         "Not all monitors support values different from 1.",
@@ -214,7 +214,7 @@ class EMEFieldMonitor(EMEMonitor, AbstractFieldMonitor):
     eme_cell_interval_space: Literal[1] = pd.Field(
         1,
         title="EME Cell Interval",
-        description="Number of eme cells between monitor recordings. If equal to 1, "
+        description="Number of EME cells between monitor recordings. If equal to 1, "
         "there will be no downsampling. If greater than 1, the step will be applied, but the "
         "first and last cells are always included. Not used in all monitors. "
         "Not all monitors support values different from 1. Note: this field is not used for "
@@ -280,12 +280,21 @@ class EMECoefficientMonitor(EMEMonitor):
     eme_cell_interval_space: pd.PositiveInt = pd.Field(
         1,
         title="EME Cell Interval",
-        description="Number of eme cells between monitor recordings. If equal to 1, "
+        description="Number of EME cells between monitor recordings. If equal to 1, "
         "there will be no downsampling. If greater than 1, the step will be applied, but the "
         "first and last cells are always included. Not used in all monitors. "
         "Not all monitors support values different from 1.",
     )
 
+    num_sweep: Optional[pd.NonNegativeInt] = pd.Field(
+        None,
+        title="Number of Sweep Indices",
+        description="Number of sweep indices for the monitor to record. "
+        "Cannot exceed the number of sweep indices for the simulation. "
+        "If the sweep does not change the monitor data, the sweep index "
+        "will be omitted. A value of 'None' will record all sweep indices.",
+    )
+
     def storage_size(
         self,
         num_cells: int,

tidy3d/components/eme/simulation.py

@@ -51,8 +51,9 @@
 
 
 # eme specific simulation parameters
-WARN_NUM_FREQS = 20
-MAX_NUM_FREQS = 500
+WARN_NUM_SAMPLING_POINTS = 20
+MAX_NUM_SAMPLING_POINTS = 500
+MAX_NUM_FREQS = 2000
 MAX_NUM_SWEEP = 100
 
 
@@ -105,7 +106,7 @@ class EMESimulation(AbstractYeeGridSimulation):
 
         **Frequency Sweeps**
 
-        Frequency sweeps are supported by including multiple frequencies in the `freqs` field. However, our EME solver repeats the mode solving for each new frequency, so frequency sweeps involving a large number of frequencies can be slow and expensive. If a large number of frequencies are required, consider using our FDTD solver instead.
+        Frequency sweeps are supported by including multiple frequencies in the `freqs` field. To avoid recomputing the modes at each frequency, the modes are interpolated according to the `EMEModeSpec.interp_spec` in the cells `eme_grid_spec`. By setting this `interp_spec`, the interpolation can be changed or disabled (repeating the solve at each frequency, which can be slow).
 
         **Passivity and Unitarity Constraints**
 
@@ -159,10 +160,9 @@ class EMESimulation(AbstractYeeGridSimulation):
         ...,
         title="Frequencies",
         description="Frequencies for the EME simulation. "
-        "The field is propagated independently at each provided frequency. "
-        "This can be slow when the number of frequencies is large. In this case, "
-        "consider using the approximate 'EMEFreqSweep' as the 'sweep_spec' "
-        "instead of providing all desired frequencies here.",
+        "The field is propagated independently at each provided frequency, "
+        "but the modes are only computed at a few sampling points and interpolated. "
+        "To change this behavior, you can use 'EMEModeSpec.interp_spec'.",
     )
 
     axis: Axis = pd.Field(
@@ -817,17 +817,23 @@ def _validate_size(self) -> None:
         if num_freqs > MAX_NUM_FREQS:
             raise SetupError(
                 f"Simulation has {num_freqs:.2e} frequencies, "
-                f"a maximum of {MAX_NUM_FREQS:.2e} are allowed. Mode solving "
-                f"is repeated at each frequency, so EME simulations with too many frequencies "
-                f"can be slower and more expensive than FDTD simulations. "
-                f"Consider using an 'EMEFreqSweep' instead for a faster approximate solution."
+                f"a maximum of {MAX_NUM_FREQS:.2e} are allowed."
             )
-        if num_freqs > WARN_NUM_FREQS:
+        num_sampling_points = self._num_sampling_points
+        if num_sampling_points > MAX_NUM_SAMPLING_POINTS:
+            raise SetupError(
+                f"Simulation has {num_sampling_points:.2e} frequency sampling points, "
+                f"a maximum of {MAX_NUM_SAMPLING_POINTS:.2e} are allowed. Mode solving "
+                f"is repeated at each sampling point, so EME simulations with too many "
+                f"frequencies can be slower and more expensive than FDTD simulations. "
+                f"Consider using 'EMEModeSpec.interp_spec' instead for a faster approximate solution."
+            )
+        if num_sampling_points > WARN_NUM_SAMPLING_POINTS:
             log.warning(
-                f"Simulation has {num_freqs:.2e} frequencies. Mode solving "
-                f"is repeated at each frequency, so EME simulations with too many frequencies "
-                f"can be slower and more expensive than FDTD simulations. "
-                f"Consider using an 'EMEFreqSweep' instead for a faster approximate solution."
+                f"Simulation has {num_sampling_points:.2e} frequency sampling points. Mode solving "
+                f"is repeated at each sampling point, so EME simulations with too many "
+                f"frequencies can be slower and more expensive than FDTD simulations. "
+                f"Consider using 'EMEModeSpec.interp_spec' instead for a faster approximate solution."
             )
 
     def _validate_monitor_size(self) -> None:
@@ -934,6 +940,18 @@ def monitors_data_size(self) -> dict[str, float]:
             data_size[monitor.name] = storage_size
         return data_size
 
+    @property
+    def _num_sampling_points(self) -> int:
+        """Max number of sampling freqs in the simulation."""
+        freqs = set()
+        for mode_spec in self.eme_grid.mode_specs:
+            interp_spec = mode_spec.interp_spec
+            if interp_spec is None:
+                freqs |= set(self.freqs)
+            else:
+                freqs |= set(interp_spec.sampling_points(self.freqs))
+        return len(freqs)
+
     @property
     def _num_sweep(self) -> pd.PositiveInt:
         """Number of sweep indices."""