use mode solver fields as default args in conversion methods

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 - Indent for the json string of Tidy3D models has been changed to `None` when used internally; kept as `indent=4` for writing to `json` and `yaml` files.
+- `freqs` and `direction` are optional in `ModeSolver` methods converting to monitor and source, respectively. If not supplied, uses the values from the `ModeSolver` instance calling the method.
 
 ### Fixed
 - Fixed the duplication of log messages in Jupyter when `set_logging_file` is used.

tests/test_plugins/test_mode_solver.py

@@ -653,3 +653,56 @@ def test_mode_solver_nan_pol_fraction():
     md = ms.solve()
 
     assert list(np.where(np.isnan(md.pol_fraction.te))[1]) == [8, 9]
+
+
+def test_mode_solver_method_defaults():
+    """Test that changes to mode solver default values in methods work."""
+
+    simulation = td.Simulation(
+        medium=td.Medium(permittivity=2),
+        size=SIM_SIZE,
+        grid_spec=td.GridSpec.auto(wavelength=1.55, min_steps_per_wvl=15),
+        run_time=1e-12,
+        symmetry=(0, 0, 1),
+        boundary_spec=td.BoundarySpec.all_sides(boundary=td.Periodic()),
+        sources=[SRC],
+    )
+
+    mode_spec = td.ModeSpec(
+        num_modes=10,
+        target_neff=3.48,
+        filter_pol="tm",
+        precision="single",
+        track_freq="central",
+    )
+
+    freqs = [td.C_0 / 1.55]
+
+    ms = ModeSolver(
+        simulation=simulation,
+        plane=td.Box(center=(0, 0, 0), size=(2, 0, 1.1)),
+        mode_spec=mode_spec,
+        freqs=freqs,
+        direction="-",
+    )
+
+    # test defaults
+    st = td.GaussianPulse(freq0=1.0, fwidth=1.0)
+
+    src = ms.to_source(source_time=st)
+    assert src.direction == ms.direction
+
+    src = ms.to_source(source_time=st, direction="+")
+    assert src.direction != ms.direction
+
+    mnt = ms.to_monitor(name="mode_mnt")
+    assert np.allclose(mnt.freqs, ms.freqs)
+
+    mnt = ms.to_monitor(name="mode_mnt", freqs=[2e14])
+    assert not np.allclose(mnt.freqs, ms.freqs)
+
+    sim = ms.sim_with_source(source_time=st)
+    assert sim.sources[-1].direction == ms.direction
+
+    sim = ms.sim_with_monitor(name="test")
+    assert np.allclose(sim.monitors[-1].freqs, ms.freqs)

tidy3d/plugins/mode/mode_solver.py

@@ -573,7 +573,7 @@ def _grid_correction(
     def to_source(
         self,
         source_time: SourceTime,
-        direction: Direction,
+        direction: Direction = None,
         mode_index: pydantic.NonNegativeInt = 0,
     ) -> ModeSource:
         """Creates :class:`.ModeSource` from a :class:`ModeSolver` instance plus additional
@@ -583,8 +583,9 @@ def to_source(
         ----------
         source_time: :class:`.SourceTime`
             Specification of the source time-dependence.
-        direction : Direction
+        direction : Direction = None
             Whether source will inject in ``"+"`` or ``"-"`` direction relative to plane normal.
+            If not specified, uses the direction from the mode solver.
         mode_index : int = 0
             Index into the list of modes returned by mode solver to use in source.
 
@@ -595,6 +596,9 @@ def to_source(
             inputs.
         """
 
+        if direction is None:
+            direction = self.direction
+
         return ModeSource(
             center=self.plane.center,
             size=self.plane.size,
@@ -604,14 +608,15 @@ def to_source(
             direction=direction,
         )
 
-    def to_monitor(self, freqs: List[float], name: str) -> ModeMonitor:
+    def to_monitor(self, freqs: List[float] = None, name: str = None) -> ModeMonitor:
         """Creates :class:`ModeMonitor` from a :class:`ModeSolver` instance plus additional
         specifications.
 
         Parameters
         ----------
         freqs : List[float]
             Frequencies to include in Monitor (Hz).
+            If not specified, passes ``self.freqs``.
         name : str
             Required name of monitor.
 
@@ -622,6 +627,15 @@ def to_monitor(self, freqs: List[float], name: str) -> ModeMonitor:
             inputs.
         """
 
+        if freqs is None:
+            freqs = self.freqs
+
+        if name is None:
+            raise ValueError(
+                "A 'name' must be passed to 'ModeSolver.to_monitor'. "
+                "The default value of 'None' is for backwards compatibility and is not accepted."
+            )
+
         return ModeMonitor(
             center=self.plane.center,
             size=self.plane.size,
@@ -663,7 +677,7 @@ def to_mode_solver_monitor(self, name: str, colocate: bool = None) -> ModeSolver
     def sim_with_source(
         self,
         source_time: SourceTime,
-        direction: Direction,
+        direction: Direction = None,
         mode_index: pydantic.NonNegativeInt = 0,
     ) -> Simulation:
         """Creates :class:`Simulation` from a :class:`ModeSolver`. Creates a copy of
@@ -674,8 +688,9 @@ def sim_with_source(
         ----------
         source_time: :class:`.SourceTime`
             Specification of the source time-dependence.
-        direction : Direction
+        direction : Direction = None
             Whether source will inject in ``"+"`` or ``"-"`` direction relative to plane normal.
+            If not specified, uses the direction from the mode solver.
         mode_index : int = 0
             Index into the list of modes returned by mode solver to use in source.
 
@@ -685,6 +700,7 @@ def sim_with_source(
             Copy of the simulation with a :class:`.ModeSource` with specifications taken
             from the ModeSolver instance and the method inputs.
         """
+
         mode_source = self.to_source(
             mode_index=mode_index, direction=direction, source_time=source_time
         )
@@ -694,17 +710,18 @@ def sim_with_source(
 
     def sim_with_monitor(
         self,
-        freqs: List[float],
-        name: str,
+        freqs: List[float] = None,
+        name: str = None,
     ) -> Simulation:
         """Creates :class:`.Simulation` from a :class:`ModeSolver`. Creates a copy of
         the ModeSolver's original simulation with a mode monitor added corresponding to
         the ModeSolver parameters.
 
         Parameters
         ----------
-        freqs : List[float]
+        freqs : List[float] = None
             Frequencies to include in Monitor (Hz).
+            If not specified, uses the frequencies from the mode solver.
         name : str
             Required name of monitor.
 
@@ -714,6 +731,7 @@ def sim_with_monitor(
             Copy of the simulation with a :class:`.ModeMonitor` with specifications taken
             from the ModeSolver instance and the method inputs.
         """
+
         mode_monitor = self.to_monitor(freqs=freqs, name=name)
         new_monitors = list(self.simulation.monitors) + [mode_monitor]
         new_sim = self.simulation.updated_copy(monitors=new_monitors)