fix(rf): validate port mesh refinement compatibility with GridSpec

[dmarek-flex]

Greptile Overview

Greptile Summary

This PR adds validation to ensure that port mesh refinement options are only used with compatible GridSpec types in TerminalComponentModeler. The validation prevents users from enabling mesh refinement features (like enable_snapping_points or num_grid_cells) when using UniformGrid, which doesn't support these features.

Key Changes:

• Added _validate_port_refinement_usage() validator in TerminalComponentModeler that checks if ports have mesh refinement enabled when the simulation uses a non-snapping grid
• Implemented _is_using_mesh_refinement property on both AbstractLumpedPort and WavePort to detect if refinement options are enabled
• Updated tests to explicitly disable mesh refinement when using uniform grids (autograd tests) or switch to QuasiUniformGrid for wave port tests
• Added test test_validate_port_refinement_with_uniform_grid() to verify the validation catches the incompatibility

The validation improves user experience by catching configuration errors early with a clear error message explaining how to fix the issue.

Confidence Score: 5/5

• This PR is safe to merge with minimal risk
• The changes are well-implemented with comprehensive test coverage, clear error messages following coding standards, and no breaking changes to existing functionality. The validation is purely additive and helps prevent configuration errors.
• No files require special attention

Important Files Changed

File Analysis

Filename	Score	Overview
tidy3d/plugins/smatrix/component_modelers/terminal.py	5/5	Adds validator to check port mesh refinement compatibility with GridSpec, preventing incompatible configurations
tidy3d/plugins/smatrix/ports/base_lumped.py	5/5	Adds property to check if lumped port uses mesh refinement options (snapping or custom cell count)
tidy3d/plugins/smatrix/ports/wave.py	5/5	Adds property to check if wave port uses mesh refinement via custom grid cell count
tests/test_plugins/smatrix/test_terminal_component_modeler.py	5/5	Updates tests to use QuasiUniformGrid for wave port tests and adds new validation test for uniform grid incompatibility

Sequence Diagram

sequenceDiagram
    participant User
    participant TerminalComponentModeler
    participant Port as AbstractPort
    participant GridSpec
    
    User->>TerminalComponentModeler: Create with simulation & ports
    TerminalComponentModeler->>TerminalComponentModeler: _validate_port_refinement_usage()
    TerminalComponentModeler->>GridSpec: Check snapped_grid_used
    alt Grid supports snapping (AutoGrid/QuasiUniform)
        GridSpec-->>TerminalComponentModeler: True
        TerminalComponentModeler-->>User: Validation passes
    else Uniform grid (no snapping support)
        GridSpec-->>TerminalComponentModeler: False
        loop For each port
            TerminalComponentModeler->>Port: Check _is_using_mesh_refinement
            alt LumpedPort with refinement
                Port-->>TerminalComponentModeler: enable_snapping_points=True OR num_grid_cells set
                TerminalComponentModeler-->>User: ValidationError
            else WavePort with refinement
                Port-->>TerminalComponentModeler: num_grid_cells set
                TerminalComponentModeler-->>User: ValidationError
            else No refinement options
                Port-->>TerminalComponentModeler: False
                TerminalComponentModeler-->>User: Validation passes
            end
        end
    end

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[dmarek-flex]

@weiliangjin2021 I noticed that QuasiUniformGrid does not appear to use internal_snapping points. Is that an issue?

tidy3d/tidy3d/components/grid/grid_spec.py

Lines 2301 to 2329 in 2ce5542

	def internal_snapping_points(
	self,
	structures: list[Structure],
	lumped_elements: list[LumpedElementType],
	cached_corners_and_convexity=None,
	) -> list[CoordinateOptional]:
	"""Internal snapping points. So far, internal snapping points are generated by
	`layer_refinement_specs` and lumped element.
	Parameters
	----------
	structures : List[Structure]
	List of physical structures.
	lumped_elements : List[LumpedElementType]
	List of lumped elements.
	cached_corners_and_convexity : Optional[list[CachedCornersAndConvexity]]
	Cached corners and convexity data.
	Returns
	-------
	List[CoordinateOptional]
	List of snapping points coordinates.
	"""
	# no need to generate anything if autogrid is not used
	if not self.auto_grid_used:
	return []
	snapping_points = []

[greptile-apps]

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[weiliangjin2021]

@weiliangjin2021 I noticed that QuasiUniformGrid does not appear to use internal_snapping points. Is that an issue?

tidy3d/tidy3d/components/grid/grid_spec.py

Lines 2301 to 2329 in 2ce5542

	def internal_snapping_points(
	self,
	structures: list[Structure],
	lumped_elements: list[LumpedElementType],
	cached_corners_and_convexity=None,
	) -> list[CoordinateOptional]:
	"""Internal snapping points. So far, internal snapping points are generated by
	`layer_refinement_specs` and lumped element.
	Parameters
	----------
	structures : List[Structure]
	List of physical structures.
	lumped_elements : List[LumpedElementType]
	List of lumped elements.
	cached_corners_and_convexity : Optional[list[CachedCornersAndConvexity]]
	Cached corners and convexity data.
	Returns
	-------
	List[CoordinateOptional]
	List of snapping points coordinates.
	"""
	# no need to generate anything if autogrid is not used
	if not self.auto_grid_used:
	return []
	snapping_points = []

both internal_snapping points and internal_override_structures are not used. The design at that time is that LayerRefinement should only take effect for AutoGrid. QuasiUniformGrid is almost uniform, and should only be used for very basic grid setup.

[github-actions]

Diff Coverage

Diff: origin/develop...HEAD, staged and unstaged changes

• tidy3d/plugins/smatrix/component_modelers/terminal.py (100%)
• tidy3d/plugins/smatrix/ports/base_lumped.py (100%)
• tidy3d/plugins/smatrix/ports/wave.py (100%)

Summary

• Total: 16 lines
• Missing: 0 lines
• Coverage: 100%

[dmarek-flex]

QuasiUniformGrid is almost uniform, and should only be used for very basic grid setup.

Very well, then I think I will change validator to check for AutoGrid

[momchil-flex]

Thanks!

[weiliangjin2021]

Nice!