fdtdx.BoundaryConfig

class fdtdx.BoundaryConfig(*, boundary_type_minx='pml', boundary_type_maxx='pml', boundary_type_miny='pml', boundary_type_maxy='pml', boundary_type_minz='pml', boundary_type_maxz='pml', thickness_grid_minx=10, thickness_grid_maxx=10, thickness_grid_miny=10, thickness_grid_maxy=10, thickness_grid_minz=10, thickness_grid_maxz=10, kappa_start_minx=None, kappa_end_minx=None, kappa_start_maxx=None, kappa_end_maxx=None, kappa_start_miny=None, kappa_end_miny=None, kappa_start_maxy=None, kappa_end_maxy=None, kappa_start_minz=None, kappa_end_minz=None, kappa_start_maxz=None, kappa_end_maxz=None, kappa_order_minx=None, kappa_order_maxx=None, kappa_order_miny=None, kappa_order_maxy=None, kappa_order_minz=None, kappa_order_maxz=None, alpha_start_minx=None, alpha_end_minx=None, alpha_start_maxx=None, alpha_end_maxx=None, alpha_start_miny=None, alpha_end_miny=None, alpha_start_maxy=None, alpha_end_maxy=None, alpha_start_minz=None, alpha_end_minz=None, alpha_start_maxz=None, alpha_end_maxz=None, alpha_order_minx=None, alpha_order_maxx=None, alpha_order_miny=None, alpha_order_maxy=None, alpha_order_minz=None, alpha_order_maxz=None, sigma_start_minx=None, sigma_end_minx=None, sigma_start_maxx=None, sigma_end_maxx=None, sigma_start_miny=None, sigma_end_miny=None, sigma_start_maxy=None, sigma_end_maxy=None, sigma_start_minz=None, sigma_end_minz=None, sigma_start_maxz=None, sigma_end_maxz=None, sigma_order_minx=None, sigma_order_maxx=None, sigma_order_miny=None, sigma_order_maxy=None, sigma_order_minz=None, sigma_order_maxz=None, bloch_vector=(0.0, 0.0, 0.0))

Bases: TreeClass

Configuration class for boundary conditions.

This class stores parameters for boundary conditions in all six directions (min/max x/y/z). Supports both PML and periodic boundaries. For PML, the parameters control the absorption properties and physical size of the PML regions.

Quick Reference

Attributes

• alpha_end_maxx

• alpha_end_maxy

• alpha_end_maxz

• alpha_end_minx

• alpha_end_miny

• alpha_end_minz

• alpha_order_maxx

• alpha_order_maxy

• alpha_order_maxz

• alpha_order_minx

• alpha_order_miny

• alpha_order_minz

• alpha_start_maxx

• alpha_start_maxy

• alpha_start_maxz

• alpha_start_minx

• alpha_start_miny

• alpha_start_minz

• bloch_vector

• boundary_type_maxx

• boundary_type_maxy

• boundary_type_maxz

• boundary_type_minx

• boundary_type_miny

• boundary_type_minz

• kappa_end_maxx

• kappa_end_maxy

• kappa_end_maxz

• kappa_end_minx

• kappa_end_miny

• kappa_end_minz

• kappa_order_maxx

• kappa_order_maxy

• kappa_order_maxz

• kappa_order_minx

• kappa_order_miny

• kappa_order_minz

• kappa_start_maxx

• kappa_start_maxy

• kappa_start_maxz

• kappa_start_minx

• kappa_start_miny

• kappa_start_minz

• sigma_end_maxx

• sigma_end_maxy

• sigma_end_maxz

• sigma_end_minx

• sigma_end_miny

• sigma_end_minz

• sigma_order_maxx

• sigma_order_maxy

• sigma_order_maxz

• sigma_order_minx

• sigma_order_miny

• sigma_order_minz

• sigma_start_maxx

• sigma_start_maxy

• sigma_start_maxz

• sigma_start_minx

• sigma_start_miny

• sigma_start_minz

• thickness_grid_maxx

• thickness_grid_maxy

• thickness_grid_maxz

• thickness_grid_minx

• thickness_grid_miny

• thickness_grid_minz

Methods

• aset

• from_uniform_bound

• get_alpha_dict

• get_class_fields

• get_dict

• get_inside_boundary_slice

• get_kappa_dict

• get_order_dict

• get_public_fields

• get_sigma_dict

• get_type_dict

Attributes

BoundaryConfig.alpha_end_maxx: float | None

Final alpha value at max x boundary. Default 0.0.

BoundaryConfig.alpha_end_maxy: float | None

Final alpha value at max y boundary. Default 0.0.

BoundaryConfig.alpha_end_maxz: float | None

Final alpha value at max z boundary. Default 0.0.

BoundaryConfig.alpha_end_minx: float | None

Final alpha value at min x boundary. Default 0.0.

BoundaryConfig.alpha_end_miny: float | None

Final alpha value at min y boundary. Default 0.0.

BoundaryConfig.alpha_end_minz: float | None

Final alpha value at min z boundary. Default 0.0.

BoundaryConfig.alpha_order_maxx: float | None

Polynomial order for alpha grading at max x boundary. Default 1.0.

BoundaryConfig.alpha_order_maxy: float | None

Polynomial order for alpha grading at max y boundary. Default 1.0.

BoundaryConfig.alpha_order_maxz: float | None

Polynomial order for alpha grading at max z boundary. Default 1.0.

BoundaryConfig.alpha_order_minx: float | None

Polynomial order for alpha grading at min x boundary. Default 1.0.

BoundaryConfig.alpha_order_miny: float | None

Polynomial order for alpha grading at min y boundary. Default 1.0.

BoundaryConfig.alpha_order_minz: float | None

Polynomial order for alpha grading at min z boundary. Default 1.0.

BoundaryConfig.alpha_start_maxx: float | None

Initial alpha value at max x boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.alpha_start_maxy: float | None

Initial alpha value at max y boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.alpha_start_maxz: float | None

Initial alpha value at max z boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.alpha_start_minx: float | None

Initial alpha value at min x boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.alpha_start_miny: float | None

Initial alpha value at min y boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.alpha_start_minz: float | None

Initial alpha value at min z boundary. Default 0.01 * 2 * jnp.pi * c / wavelength * eps0.

BoundaryConfig.bloch_vector: tuple[float, float, float]

Bloch wave vector (k_x, k_y, k_z) in rad/m. Each component provides the phase shift for the corresponding axis when that axis uses “bloch” boundaries. The full 3D vector is stored on every BlochBoundary; each boundary extracts the component along its own axis to compute exp(i * k_axis * L_axis).

BoundaryConfig.boundary_type_maxx: str

Boundary type at maximum x (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.boundary_type_maxy: str

Boundary type at maximum y (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.boundary_type_maxz: str

Boundary type at maximum z (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.boundary_type_minx: str

Boundary type at minimum x (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.boundary_type_miny: str

Boundary type at minimum y (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.boundary_type_minz: str

Boundary type at minimum z (“pml”, “periodic”, “pec”, “pmc”, or “bloch”). Default “pml”.

BoundaryConfig.kappa_end_maxx: float | None

Final kappa value at max x boundary. Default 1.0.

BoundaryConfig.kappa_end_maxy: float | None

Final kappa value at max y boundary. Default 1.0.

BoundaryConfig.kappa_end_maxz: float | None

Final kappa value at max z boundary. Default 1.0.

BoundaryConfig.kappa_end_minx: float | None

Final kappa value at min x boundary. Default 1.0.

BoundaryConfig.kappa_end_miny: float | None

Final kappa value at min y boundary. Default 1.0.

BoundaryConfig.kappa_end_minz: float | None

Final kappa value at min z boundary. Default 1.0.

BoundaryConfig.kappa_order_maxx: float | None

Polynomial order for kappa grading at max x boundary. Default 1.0.

BoundaryConfig.kappa_order_maxy: float | None

Polynomial order for kappa grading at max y boundary. Default 1.0.

BoundaryConfig.kappa_order_maxz: float | None

Polynomial order for kappa grading at max z boundary. Default 1.0.

BoundaryConfig.kappa_order_minx: float | None

Polynomial order for kappa grading at min x boundary. Default 1.0.

BoundaryConfig.kappa_order_miny: float | None

Polynomial order for kappa grading at min y boundary. Default 1.0.

BoundaryConfig.kappa_order_minz: float | None

Polynomial order for kappa grading at min z boundary. Default 1.0.

BoundaryConfig.kappa_start_maxx: float | None

Initial kappa value at max x boundary. Default 1.0.

BoundaryConfig.kappa_start_maxy: float | None

Initial kappa value at max y boundary. Default 1.0.

BoundaryConfig.kappa_start_maxz: float | None

Initial kappa value at max z boundary. Default 1.0.

BoundaryConfig.kappa_start_minx: float | None

Initial kappa value at min x boundary. Default 1.0.

BoundaryConfig.kappa_start_miny: float | None

Initial kappa value at min y boundary. Default 1.0.

BoundaryConfig.kappa_start_minz: float | None

Initial kappa value at min z boundary. Default 1.0.

BoundaryConfig.sigma_end_maxx: float | None

Final sigma value at max x boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_end_maxy: float | None

Final sigma value at max y boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_end_maxz: float | None

Final sigma value at max z boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_end_minx: float | None

Final sigma value at min x boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_end_miny: float | None

Final sigma value at min y boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_end_minz: float | None

Final sigma value at min z boundary. Default -(3.0 + 1) * jnp.log(1e-6) / (2 * (eta0 / 1.0) * (self.thickness * self._config.uniform_spacing())).

BoundaryConfig.sigma_order_maxx: float | None

Polynomial order for sigma grading at max x boundary. Default 3.0.

BoundaryConfig.sigma_order_maxy: float | None

Polynomial order for sigma grading at max y boundary. Default 3.0.

BoundaryConfig.sigma_order_maxz: float | None

Polynomial order for sigma grading at max z boundary. Default 3.0.

BoundaryConfig.sigma_order_minx: float | None

Polynomial order for sigma grading at min x boundary. Default 3.0.

BoundaryConfig.sigma_order_miny: float | None

Polynomial order for sigma grading at min y boundary. Default 3.0.

BoundaryConfig.sigma_order_minz: float | None

Polynomial order for sigma grading at min z boundary. Default 3.0.

BoundaryConfig.sigma_start_maxx: float | None

Initial sigma value at max x boundary. Default 0.0.

BoundaryConfig.sigma_start_maxy: float | None

Initial sigma value at max y boundary. Default 0.0.

BoundaryConfig.sigma_start_maxz: float | None

Initial sigma value at max z boundary. Default 0.0.

BoundaryConfig.sigma_start_minx: float | None

Initial sigma value at min x boundary. Default 0.0.

BoundaryConfig.sigma_start_miny: float | None

Initial sigma value at min y boundary. Default 0.0.

BoundaryConfig.sigma_start_minz: float | None

Initial sigma value at min z boundary. Default 0.0.

BoundaryConfig.thickness_grid_maxx: int

Number of grid cells for PML at maximum x boundary. Default 10.

BoundaryConfig.thickness_grid_maxy: int

Number of grid cells for PML at maximum y boundary. Default 10.

BoundaryConfig.thickness_grid_maxz: int

Number of grid cells for PML at maximum z boundary. Default 10.

BoundaryConfig.thickness_grid_minx: int

Number of grid cells for PML at minimum x boundary. Default 10.

BoundaryConfig.thickness_grid_miny: int

Boundary type at minimum y (“pml” or “periodic”). Default “pml”.

BoundaryConfig.thickness_grid_minz: int

Number of grid cells for PML at minimum z boundary. Default 10.

Methods

BoundaryConfig.aset(attr_name, val, create_new_ok=False)

Sets an attribute of this class. In contrast to the classical .at[].set(), this method updates the class attribute directly and does not only operate on jax pytree leaf nodes. Instead, replaces the full attribute with the new value.

The attribute can either be the attribute name of this class, or for nested classes it can also be the attribute name of a class, which itself is an attribute of this class. The syntax for this operation could look like this: “a->b->[0]->[‘name’]”. Here, the current class has an attribute a, which has an attribute b, which is a list, which we index at index 0, which is an element of type dictionary, which we index using the dictionary key ‘name’.

Note that dictionary keys cannot contain square brackets or single quotes (even if they are escaped).

Parameters:

• attr_name (str) – Name of attribute to set

• val (Any) – Value to set the attribute to

• create_new_ok (bool, optional) – If false (default), throw an error if the attribute does not exist. If true, creates a new attribute if the attribute name does not exist yet.

Returns:

Updated instance with new attribute value

Return type:

Self

classmethod BoundaryConfig.from_uniform_bound(thickness=10, boundary_type='pml', kappa_start=None, kappa_end=None, kappa_order=None, alpha_start=None, alpha_end=None, alpha_order=None, sigma_start=None, sigma_end=None, sigma_order=None, override_types=None, bloch_vector=(0.0, 0.0, 0.0))

Creates a BoundaryConfig with uniform parameters for all boundaries.

Parameters:

• thickness (int, optional) – Grid thickness to use for all PML boundaries. Defaults to 10.

• boundary_type (str, optional) – Type of boundary to use (“pml” or “periodic”). Defaults to “pml”.

• kappa_start (float, optional) – Initial kappa value for all boundaries. Defaults to 1.0.

• kappa_end (float, optional) – Final kappa value for all boundaries. Defaults to 1.5.

• kappa_order (float, optional) – Polynomial order for kappa grading at all boundaries. Defaults to 1.0.

• alpha_start (float, optional) – Initial alpha value for all boundaries. Defaults to 1e-8.

• alpha_end (float, optional) – Final alpha value for all boundaries. Defaults to 1e-8.

• alpha_order (float, optional) – Polynomial order for alpha grading at all boundaries. Defaults to 1.0.

• sigma_start (float, optional) – Initial sigma value for all boundaries. Defaults to 0.0.

• sigma_end (float, optional) – Final sigma value for all boundaries. Defaults to 1.0.

• sigma_order (float, optional) – Polynomial order for sigma grading at all boundaries. Defaults to 3.0.

• override_types (dict[str, str], optional) – Dictionary mapping specific boundaries (“min_x”, “max_x”, “min_y”, “max_y”, “min_z”, “max_z”) to their boundary types (“pml”, “periodic”), overriding the global boundary_type. Defaults to None.

• bloch_vector (tuple[float, float, float], optional) – Bloch wave vector (k_x, k_y, k_z) in rad/m. Each component sets the phase shift for the corresponding axis. Defaults to (0, 0, 0).

Returns:

New config object with uniform parameters

Return type:

BoundaryConfig

BoundaryConfig.get_alpha_dict(prop)

Gets a dictionary mapping boundary names to their alpha values.

Parameters:

prop (Literal["alpha_start", "alpha_end"]) – Which alpha property to get, either “alpha_start” or “alpha_end”.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective alpha values.

Return type:

dict[str, float | None]

Raises:

Exception – If prop is not “alpha_start” or “alpha_end”

BoundaryConfig.get_class_fields()

Return type:

list[TreeClassField]

BoundaryConfig.get_dict()

Gets a dictionary mapping boundary names to their grid thicknesses.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective grid thickness values.

Return type:

dict[str, int]

BoundaryConfig.get_inside_boundary_slice()

Gets slice objects for the non-PML interior region of the simulation volume.

Returns:

Three slice objects for indexing the x, y, z dimensions

respectively, excluding the PML boundary regions.

Return type:

tuple[slice, slice, slice]

BoundaryConfig.get_kappa_dict(prop)

Gets a dictionary mapping boundary names to their kappa values.

Parameters:

prop (Literal["kappa_start", "kappa_end"]) – Which kappa property to get, either “kappa_start” or “kappa_end”.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective kappa values.

Return type:

dict[str, float | None]

Raises:

Exception – If prop is not “kappa_start” or “kappa_end”

BoundaryConfig.get_order_dict(prop)

Gets a dictionary mapping boundary names to their polynomial order values.

Parameters:

prop (Literal["sigma_order", "alpha_order", "kappa_order"]) – Which order property to get.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective order values.

Return type:

dict[str, float | None]

Raises:

Exception – If prop is not one of the valid options

BoundaryConfig.get_public_fields()

Return type:

list[TreeClassField]

BoundaryConfig.get_sigma_dict(prop)

Gets a dictionary mapping boundary names to their sigma values.

Parameters:

prop (Literal["sigma_start", "sigma_end"]) – Which sigma property to get, either “sigma_start” or “sigma_end”.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective sigma values.

Return type:

dict[str, float | None]

Raises:

Exception – If prop is not “sigma_start” or “sigma_end”

BoundaryConfig.get_type_dict()

Gets a dictionary mapping boundary names to their boundary types.

Returns:

Dictionary with keys ‘min_x’, ‘max_x’, ‘min_y’, ‘max_y’, ‘min_z’, ‘max_z’

mapping to their respective boundary types (“pml” or “periodic”).

Return type:

dict[str, str]

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