Dispersion and Response¶

Contract¶

This page records the dispersion-curve and frequency-response observables attached to eigenmode and frequency-response studies.

Governing equations¶

Response and dispersion definitions belong to Frequency-domain response and Linearized-LLG eigensolvers.

Symbols and SI units¶

Eigenfrequency values are in hertz; response observables carry the units of their definition.

Assumptions and validity¶

Response observable identifiers and dispersion names are validated immediately.

Python API¶

Supported response observables include susceptibility_tensor, m_complex, u_complex, strain_complex, stress_complex, absorbed_power_density, response_amplitude, response_phase, and mode_hybridization_index.

# %% Frequency response with a susceptibility observable
import fullmag as fm

nm = 1.0e-9

study = fm.study("dispersion_response_api_example")
study.engine("fdm")
study.device("cpu", precision="double")
study.mode("strict")

study.objects.mesh.defaults(cell_size=(2 * nm, 2 * nm, 5 * nm))
film = study.geometry(fm.Box(100 * nm, 20 * nm, 5 * nm), name="film")
film.Ms = 800.0e3
film.Aex = 13.0e-12
film.alpha = 0.02
film.m = fm.init.UniformMagnetization((1.0, 0.0, 0.0))
study.exchange()
study.stages.add_relax(stage_id="relax", algorithm="projected_gradient_bb", max_steps=1000, tolT=1e-8)
study.save_response("susceptibility_tensor")
study.stages.add_frequency_response(
    frequencies_hz=[1.0e9, 2.0e9],
    excitation_field_au_per_m=(0.0, 1.0, 0.0),
    equilibrium_source="relax",
)

ProblemIR¶

SaveDispersion.to_ir() emits dispersion_curve; SaveResponse.to_ir() emits frequency_response_output. Both are carried in the study’s sampling.outputs.

Round-trip and failure semantics¶

Requested intent is the value authored by Python and preserved in ProblemIR; resolved execution is the planner or realization result. Validation errors identify the violated domain rule, and unsupported combinations are rejected explicitly rather than silently substituted.

Unknown response observables fail immediately; dispersion names are preserved without interpretation.

Discrete realization¶

Response materialization follows the frequency-domain solvers; dispersion follows the eigensolver.

Implementation mapping¶

Anchor: packages/fullmag-py/src/fullmag/model/outputs.py (SaveDispersion, SaveResponse).

Validation¶

Ownership tests compare this inventory with live signatures.

Limitations¶

Requesting an output does not guarantee the solver materializes it; planner and solver capability resolution are authoritative.

Scientific bibliography¶

Definitions belong to the frequency-domain and eigensolver pages.

Control Room crosswalk¶

Status: Table/field autosave and result inspection are partial; unsupported output formats remain not implemented.

not implemented: frontend support for output parameters not rendered by the autosave/result inspectors. See Control Room capability register for the support matrix and not implemented policy. Frontend source owner: apps/control-room/src/modules/inspector/panels/stages/AutosaveStageInspector.tsx (AutosaveStageInspector).

Source-code index¶