Change EME validation to only depend on transverse grids (FXC-3746)

CHANGELOG.md

@@ -71,6 +71,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Fixed frequency sampling of `TransmissionLineDataset` within `MicrowaveModeData` when using group index calculation.
 - Fixed DRC parsing for quoted categories in klayout plugin.
 - Removed mode solver warnings about evaluating permittivity of a `Medium2D`.
+- Maximum number of grid points in an EME simulation is now based solely on transverse grid points. Maximum number of EME cells is unchanged.
 
 ### Removed
 - Removed deprecated `use_complex_fields` parameter from `TwoPhotonAbsorption` and `KerrNonlinearity`. Parameters `beta` and `n2` are now real-valued only, as is `n0` if specified.

tests/test_components/test_eme.py

@@ -412,16 +412,10 @@ def test_eme_simulation():
         _ = sim.updated_copy(monitors=[monitor])
 
     # test max sim size and freqs
-    sim_bad = sim.updated_copy(size=(1000, 1000, 1000))
+    sim_bad = sim.updated_copy(size=(150, 150, 3))
     with pytest.raises(SetupError):
         sim_bad.validate_pre_upload()
-    sim_bad = sim.updated_copy(size=(1000, 500, 3), monitors=[], store_port_modes=True)
-    with pytest.raises(SetupError):
-        sim_bad.validate_pre_upload()
-    sim_bad = sim.updated_copy(size=(1000, 500, 3), monitors=[], store_port_modes=False)
-    with pytest.raises(SetupError):
-        sim_bad.validate_pre_upload()
-    sim_bad = sim.updated_copy(size=(500, 500, 3), monitors=[])
+    sim_bad = sim.updated_copy(size=(50, 50, 3), monitors=[])
     with AssertLogLevel("WARNING", "slow-down"):
         sim_bad.validate_pre_upload()
 

tidy3d/components/eme/simulation.py

@@ -43,11 +43,11 @@
 from .sweep import EMEFreqSweep, EMELengthSweep, EMEModeSweep, EMEPeriodicitySweep, EMESweepSpecType
 
 # maximum numbers of simulation parameters
-MAX_GRID_CELLS = 20e9
 WARN_MONITOR_DATA_SIZE_GB = 10
 MAX_MONITOR_INTERNAL_DATA_SIZE_GB = 50
 MAX_SIMULATION_DATA_SIZE_GB = 50
 WARN_MODE_NUM_CELLS = 1e5
+MAX_MODE_NUM_CELLS = 5e6
 
 
 # eme specific simulation parameters
@@ -807,14 +807,6 @@ def _validate_monitor_setup(self) -> None:
 
     def _validate_size(self) -> None:
         """Ensures the simulation is within size limits before simulation is uploaded."""
-
-        num_comp_cells = self.num_cells / 2 ** (np.sum(np.abs(self.symmetry)))
-        if num_comp_cells > MAX_GRID_CELLS:
-            raise SetupError(
-                f"Simulation has {num_comp_cells:.2e} computational cells, "
-                f"a maximum of {MAX_GRID_CELLS:.2e} are allowed."
-            )
-
         num_freqs = len(self.freqs)
         if num_freqs > MAX_NUM_FREQS:
             raise SetupError(
@@ -876,6 +868,12 @@ def _validate_modes_size(self) -> None:
         def warn_mode_size(monitor: AbstractModeMonitor, msg_header: str, custom_loc: list) -> None:
             """Warn if a mode component has a large number of points."""
             num_cells = np.prod(self.discretize_monitor(monitor).num_cells)
+            if num_cells > MAX_MODE_NUM_CELLS:
+                raise SetupError(
+                    msg_header + f"has {num_cells:.2e} computational cells "
+                    "in the transverse directions, "
+                    f"a maximum of {MAX_MODE_NUM_CELLS:.2e} are allowed."
+                )
             if num_cells > WARN_MODE_NUM_CELLS:
                 consolidated_logger.warning(
                     msg_header + f"has a large number ({num_cells:1.2e}) of grid points. "