Minor fixes to docstrings and import error messages

tidy3d/components/geometry.py

@@ -3402,15 +3402,20 @@ class TriangleMesh(Geometry, ABC):
         description="Surface mesh data.",
     )
 
-    @pydantic.root_validator(pre=True)
-    def _check_trimesh_library(cls, values):
+    @classmethod
+    def _check_trimesh_library(cls):
         """Check if the trimesh package is imported."""
         if not TRIMESH_AVAILABLE:
             raise ImportError(
                 "The package 'trimesh' was not found. Please install the 'trimesh' "
                 "dependencies to use 'TriangleMesh'. For example: "
                 "pip install -r requirements/trimesh.txt."
             )
+
+    @pydantic.root_validator(pre=True)
+    def _validate_trimesh_library(cls, values):
+        """Check if the trimesh package is imported as a validator."""
+        cls._check_trimesh_library()
         return values
 
     @pydantic.validator("mesh_dataset", pre=True, always=True)
@@ -3492,6 +3497,8 @@ def process_single(mesh: trimesh.Trimesh) -> TriangleMesh:
             mesh.apply_translation(origin)
             return cls.from_trimesh(mesh)
 
+        cls._check_trimesh_library()
+
         scene = trimesh.load(filename, **kwargs)
         meshes = []
         if isinstance(scene, trimesh.Trimesh):
@@ -3587,6 +3594,9 @@ def from_vertices_faces(cls, vertices: np.ndarray, faces: np.ndarray) -> Triangl
             The custom surface mesh geometry given by the vertices and faces provided.
 
         """
+
+        cls._check_trimesh_library()
+
         vertices = np.array(vertices)
         faces = np.array(faces)
         if len(vertices.shape) != 2 or vertices.shape[1] != 3:
@@ -3600,6 +3610,8 @@ def from_vertices_faces(cls, vertices: np.ndarray, faces: np.ndarray) -> Triangl
     @classmethod
     def _triangles_to_trimesh(cls, triangles: np.ndarray) -> trimesh.Trimesh:
         """Convert an (N, 3, 3) numpy array of triangles to a ``trimesh.Trimesh``."""
+
+        cls._check_trimesh_library()
         return trimesh.Trimesh(**trimesh.triangles.to_kwargs(triangles))
 
     @cached_property

tidy3d/components/medium.py

@@ -857,7 +857,9 @@ def from_medium(cls, medium: Medium) -> "PoleResidue":
             The pole residue equivalent.
         """
         poles = [(0, medium.conductivity / (2 * EPSILON_0))]
-        return PoleResidue(eps_inf=medium.permittivity, poles=poles)
+        return PoleResidue(
+            eps_inf=medium.permittivity, poles=poles, frequency_range=medium.frequency_range
+        )
 
     def to_medium(self) -> Medium:
         """Convert to a :class:`.Medium`.
@@ -875,7 +877,11 @@ def to_medium(self) -> Medium:
                 raise ValidationError("Cannot convert dispersive 'PoleResidue' to 'Medium'.")
             res += (c + np.conj(c)) / 2
         sigma = res * 2 * EPSILON_0
-        return Medium(permittivity=self.eps_inf, conductivity=np.real(sigma))
+        return Medium(
+            permittivity=self.eps_inf,
+            conductivity=np.real(sigma),
+            frequency_range=self.frequency_range,
+        )
 
 
 class Sellmeier(DispersiveMedium):
@@ -1400,7 +1406,7 @@ def get_background(comp: Axis) -> PoleResidue:
             ax_coord=media_bg[axis], plane_coords=media_fg_weighted, axis=axis
         )
         media_3d_kwargs = {dim + dim: medium for dim, medium in zip("xyz", media_3d)}
-        return AnisotropicMedium(**media_3d_kwargs)
+        return AnisotropicMedium(**media_3d_kwargs, frequency_range=self.frequency_range)
 
     def to_anisotropic_medium(self, axis: Axis, thickness: float) -> AnisotropicMedium:
         """Generate a 3D :class:`.AnisotropicMedium` equivalent of a given thickness.
@@ -1422,7 +1428,7 @@ def to_anisotropic_medium(self, axis: Axis, thickness: float) -> AnisotropicMedi
         media_weighted = [self._weighted_avg([medium], [1 / thickness]) for medium in media]
         media_3d = Geometry.unpop_axis(ax_coord=Medium(), plane_coords=media_weighted, axis=axis)
         media_3d_kwargs = {dim + dim: medium for dim, medium in zip("xyz", media_3d)}
-        return AnisotropicMedium(**media_3d_kwargs)
+        return AnisotropicMedium(**media_3d_kwargs, frequency_range=self.frequency_range)
 
     def to_pole_residue(self, thickness: float) -> PoleResidue:
         """Generate a :class:`.PoleResidue` equivalent of a given thickness.
@@ -1438,7 +1444,9 @@ def to_pole_residue(self, thickness: float) -> PoleResidue:
         :class:`.PoleResidue`
             The 3D equivalent pole residue model of this 2D medium.
         """
-        return self._weighted_avg([self.ss, self.tt], [1 / (2 * thickness), 1 / (2 * thickness)])
+        return self._weighted_avg(
+            [self.ss, self.tt], [1 / (2 * thickness), 1 / (2 * thickness)]
+        ).updated_copy(frequency_range=self.frequency_range)
 
     def to_medium(self, thickness: float) -> Medium:
         """Generate a :class:`.Medium` equivalent of a given thickness.
@@ -1455,9 +1463,7 @@ def to_medium(self, thickness: float) -> Medium:
         :class:`.Medium`
             The 3D equivalent of this 2D medium.
         """
-        return self._weighted_avg(
-            [self.ss, self.tt], [1 / (2 * thickness), 1 / (2 * thickness)]
-        ).to_medium()
+        return self.to_pole_residue(thickness=thickness).to_medium()
 
     @classmethod
     def from_medium(cls, medium: Medium, thickness: float) -> Medium2D:
@@ -1477,7 +1483,7 @@ def from_medium(cls, medium: Medium, thickness: float) -> Medium2D:
             The 2D equivalent of the given 3D medium.
         """
         med = cls._weighted_avg([medium], [thickness])
-        return Medium2D(ss=med, tt=med)
+        return Medium2D(ss=med, tt=med, frequency_range=medium.frequency_range)
 
     @classmethod
     def from_dispersive_medium(cls, medium: DispersiveMedium, thickness: float) -> Medium2D:
@@ -1497,7 +1503,7 @@ def from_dispersive_medium(cls, medium: DispersiveMedium, thickness: float) -> M
             The 2D equivalent of the given 3D medium.
         """
         med = cls._weighted_avg([medium], [thickness])
-        return Medium2D(ss=med, tt=med)
+        return Medium2D(ss=med, tt=med, frequency_range=medium.frequency_range)
 
     @classmethod
     def from_anisotropic_medium(
@@ -1528,7 +1534,7 @@ def from_anisotropic_medium(
         for _, med in enumerate(media_plane):
             media_plane_scaled.append(cls._weighted_avg([med], [thickness]))
         media_kwargs = {dim + dim: medium for dim, medium in zip("st", media_plane_scaled)}
-        return Medium2D(**media_kwargs)
+        return Medium2D(**media_kwargs, frequency_range=medium.frequency_range)
 
     @ensure_freq_in_range
     def eps_model(self, frequency: float) -> complex:

tidy3d/material_library/parametric_materials.py

@@ -3,12 +3,19 @@
 from typing import List, Tuple
 import pydantic as pd
 import numpy as np
-from scipy import integrate
 
 from ..components.medium import PoleResidue, Medium2D, Drude
 from ..components.base import Tidy3dBaseModel
 from ..constants import EPSILON_0, Q_e, HBAR, K_B, ELECTRON_VOLT, KELVIN
 
+try:
+    from scipy import integrate
+
+    INTEGRATE_AVAILABLE = True
+except ImportError:
+    INTEGRATE_AVAILABLE = False
+
+
 # default values of the physical parameters for graphene
 # scattering rate in eV
 GRAPHENE_DEF_GAMMA = 0.00041
@@ -45,12 +52,15 @@ def medium(self) -> Medium2D:
 
 
 class Graphene(ParametricVariantItem2D):
-    """Surface conductivity model for graphene, including intraband and interband terms,
-    as described in
+    """Parametric surface conductivity model for graphene.
 
-    George W. Hanson, "Dyadic Green's Functions for an Anisotropic,
-    Non-Local Model of Biased Graphene," IEEE Trans. Antennas Propag.
-    56, 3, 747-757 (2008).
+    Note
+    ----
+    The model contains intraband and interband terms, as described in::
+
+        George W. Hanson, "Dyadic Green's Functions for an Anisotropic,
+        Non-Local Model of Biased Graphene," IEEE Trans. Antennas Propag.
+        56, 3, 747-757 (2008).
 
     Example
     -------
@@ -215,6 +225,13 @@ def integrand(E: float, omega: float) -> float:
             """Integrand for interband term."""
             return (fermi_g(E * HBAR) - fermi_g(HBAR * omega / 2)) / (omega**2 - 4 * E**2)
 
+        if not INTEGRATE_AVAILABLE:
+            raise ImportError(
+                "The package 'scipy' was not found. Please install the 'core' "
+                "dependencies to calculate the interband term of graphene. For example: "
+                "pip install -r requirements/core.txt"
+            )
+
         omegas = 2 * np.pi * np.array(freqs)
         sigma = np.zeros(len(omegas), dtype=complex)
         integration_min = GRAPHENE_INT_MIN