Field Refresh¶

Contract¶

This page records the cadence control for expensive field/operator refreshes during dynamics.

Governing equations¶

No physical equation is introduced; refresh cadence is a numerical-efficiency policy.

Symbols and SI units¶

demag_interval_s is in seconds of simulation time.

Assumptions and validity¶

The demagnetization refresh interval must be positive when set.

Python API¶

The stage-first builder spells the same cadence as study.solver(..., demag_interval_s=...); FieldRefreshPolicy is the underlying model object lowered into the LLG dynamics record.

# %% Attach a demag refresh cadence to fixed-step dynamics
import fullmag as fm

nm = 1.0e-9

study = fm.study("field_refresh_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.solver(
    integrator="heun",
    fix_dt=5.0e-13,
    gamma=2.211e5,
    demag_interval_s=1.0e-11,
)
study.stages.add_run(stage_id="run", until=1.0e-12)

ProblemIR¶

FieldRefreshPolicy.to_ir() emits {"demag_interval_s": ...} when set, attached as dynamics.field_refresh.

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.

Non-positive intervals fail immediately. Unavailable caveats still require executed evidence from the selected backend.

Discrete realization¶

The cadence is consumed by demag-assembly schedules in the selected backend lane.

Implementation mapping¶

Anchor: packages/fullmag-py/src/fullmag/model/dynamics.py (class FieldRefreshPolicy).

Validation¶

Ownership tests compare this inventory with live signatures.

Limitations¶

Cadence control is an efficiency hint; solver correctness must not depend on refresh frequency.

Scientific bibliography¶

No physical model is introduced.

Control Room crosswalk¶

Status: Common solver/stage fields are partial; backend-specific options without editor fields remain not implemented.

not implemented: frontend support for dynamics parameters not rendered by the stage editor. See Control Room capability register for the support matrix and not implemented policy. Frontend source owner: apps/control-room/src/modules/inspector/panels/StudyStageDraftEditor.tsx (StudyStageDraftEditor).

Source-code index¶