fdtdx.Pole

fdtdx.Pole#

class fdtdx.Pole[source]#

Bases: TreeClass, ABC

Abstract base class for a single 2nd-order ADE pole.

Concrete subclasses store physically-meaningful parameters (e.g. delta_epsilon for Lorentz, omega_p for Drude) and expose the unified (omega_0, gamma, coupling_sq) triplet the FDTD loop needs via per-axis properties. New pole types can subclass Pole as long as they fit the 2nd-order ODE form.

Every parameter may differ per grid axis (diagonally anisotropic dispersion); the canonical accessors are the *_axes properties returning (x, y, z) tuples. The scalar accessors (omega_0 etc.) are a convenience for isotropic poles and raise for per-axis ones.

Quick Reference#

Attributes

Methods

Attributes#

Pole.coupling_edot#

Coefficient b of the dE/dt driving term (rad/s).

Raises ValueError for per-axis poles; use coupling_edot_axes.

Pole.coupling_edot_axes#

Per-axis coefficient b of the dE/dt driving term (rad/s).

Zero for Lorentz and Drude poles (their susceptibility numerator has no omega term). A non-zero value is what distinguishes a general complex-conjugate pole-residue (CCPR) pole — it corresponds to a non-zero real part of the residue and adds the b E' term to the ADE. Defaults to all-zero so existing pole types need not override it.

Pole.coupling_sq#

Effective squared coupling frequency K (rad^2/s^2).

Raises ValueError for per-axis poles; use coupling_sq_axes.

Pole.coupling_sq_axes#

Per-axis effective squared coupling frequency K (rad^2/s^2).

delta_epsilon * omega_0**2 for a Lorentz pole and omega_p**2 for a Drude pole.

This is the coefficient a of the E driving term in the unified 2nd-order ODE p'' + gamma p' + omega_0**2 p = a E + b E'.

Pole.gamma#

Damping rate (rad/s).

Raises ValueError for per-axis poles; use gamma_axes.

Pole.gamma_axes#

Per-axis damping rate (rad/s).

Pole.is_isotropic#

Whether all pole parameters are identical on the three axes.

Pole.omega_0#

Resonance angular frequency (rad/s). Zero for pure Drude poles.

Raises ValueError for per-axis poles; use omega_0_axes.

Pole.omega_0_axes#

Per-axis resonance angular frequency (rad/s). Zero for pure Drude poles.

Methods#

Pole.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

Pole.get_class_fields()#
Return type:

list[TreeClassField]

Pole.get_public_fields()#
Return type:

list[TreeClassField]

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