Support Boundaries

This page summarizes the public support scope for user-facing rfx workflows.

Status	Meaning
recommended default	best place to start for public examples and ordinary RF workflows
limited	usable only within the stated geometry, mesh, frequency, or calculator limits
outside documented scope	available code may exist, but public claims require a guide and support-matrix entry
unsupported	should fail clearly rather than degrade silently

Dimension	Recommended subset
grid / runner	uniform Cartesian Yee
precision	float32 default; float64 and mixed are uniform-single-device only, with the documented CPML residual-floor caveat for mixed
boundaries	PEC, CPML, and UPML within its documented limits
sources	point/current, lumped port, wire port, specialized microstrip-line port, rectangular waveguide port
observables	probes, flux, Harminv resonance, selected S-parameter workflows, documented far-field workflows
materials	isotropic linear, conductive, documented dispersive subsets, and patterned one-cell surface-impedance sheets only within their stated lane restrictions
workflows	cavity, waveguide, patch-style resonance, simple scattering, de-embedding, selected differentiable proxy objectives
non-uniform profiles	feature-specific limited or experimental scope; use the Non-Uniform Mesh guide for axis and calculator restrictions

Primitive	Calculation API	Public status
lumped/wire add_port(...)	run(compute_s_params=True)	documented calculator for the matching port family; use only within its stated validation limits
lumped/wire add_port(...)	forward(port_s11_freqs=...)	differentiable S11 vectors on the uniform single-device configuration
add_msl_port(...)	compute_msl_s_matrix()	specialized microstrip-line workflow; Laplace/quasi-TEM directions +x, -x, +y, and -y; eigenmode remains x-only and outside the public support envelope
add_waveguide_port(...)	compute_waveguide_s_matrix()	rectangular waveguide workflow, limited. Differentiation through eps_override/sigma_override runs on normalize=False and normalize="flux" only; normalize=True is host-assembled and raises NotImplementedError for a traced override. Multimode (n_modes>1) is host-assembled and outside the differentiable chain. S is a modal voltage-wave ratio referenced to each port’s own discrete modal impedance, so it is a power-wave S only when all ports share one cross-section. Magnitude evidence for uniform single-mode guides is broader than phase, junction, and nonuniform evidence, Chain battery: chain-closed (v1.8) for uniform single-mode S on the normalize=False and normalize="flux" lanes. Contract criteria 1 and 3(a) are read under JAX_ENABLE_X64 on the flux lane, so a float32 gradient pipeline there is outside the declaration. Chain-closed is not supported — this row stays limited. The full row, including the battery verdict and the JAX_ENABLE_X64 dtype rule, is in docs/guides/support_matrix.md (Rectangular-waveguide S-matrix) and docs/guides/sparameter_support_matrix.md.
add_coaxial_port(...)	compute_coaxial_line_reflection(...)	precision="float32"; nonperiodic 3D second-order uniform Yee grid; CPML on all six boundary faces with positive thickness on both z faces; cpml_axes="z"; exactly one face="top" coaxial port; see Sources and Ports for rejected registrations and accepted arguments
sources, TFSF, probes, flux monitors	not port calculators	field/flux/time observables

Some repository code exists only for backward compatibility or internal testing. Treat it as supported public API only when a public guide documents the workflow and the support matrix lists it.

These tools record and reproduce local runs. A valid spec, completed run, passing replay, or comparison report does not validate electromagnetic accuracy. Apply the documented limits for the selected mesh, source, port, and observable, and perform the required convergence or reference comparison. Studio plots only the result types listed in Studio, CLI, and MCP Experiments; other artifacts may still be available through the CLI, API, MCP, or replay bundle. MCP operations that change data or start costly work require server-side approval.

Unsupported means the run or the request must fail rather than return a number. These four are named in the nonuniform-mesh classification table of docs/guides/support_matrix.md:

Combination	Required failure
Periodic/Floquet port + nonuniform mesh	“Preflight or the calculation must fail.”
boundary="upml" + nonuniform mesh	“The run must fail. The non-uniform runner has no UPML implementation — its absorber dispatch keys on the CPML layer count and never reads the boundary type — so this combination was accepted and silently ran CPML while sim._boundary still reported upml (issue #680). Use boundary='cpml' on a graded mesh.”
Lumped-port S-parameters + nonuniform mesh	“The S-parameter request must fail.”
Coaxial port + nonuniform mesh	“The request must fail.”

Calling a calculator with the wrong port family, or reading a field probe or flux monitor as an impedance-defined port, is unsupported for the same reason: neither has a port impedance or an S-matrix reference plane.

If a workflow is not in the recommended configuration or a stated limited configuration in these tables, the linked feature guide, or the support matrices, present it as outside the documented public support scope. A successful preflight or completed run does not expand that scope.

Touchstone files, plots, HDF5 snapshots, CSV sweep tables, and JSON manifests preserve what a run produced, but they do not establish that the underlying calculation is supported or accurate. Public reports should include the port/source family, support status, command, git SHA, and pass/fail metric.