Demonstrate LVS with KLayout

[Copilot]

Adds a KLayout LVS deck for layout-vs-schematic verification of superconducting quantum circuits, with Jinja2 templating for maintainability and documentation explaining the full flow.

New layers

• Port layers (PORT_M1 1/10, PORT_M2 2/10) for net terminal detection per metal
• Device marker layers (MK_TRANSMON 200/0, MK_RESONATOR 201/0, MK_INDUCTOR 202/0, MK_CAPACITOR 203/0, MK_JJ 204/0) for component identification via boolean AND with physical layers

LVS deck (qpdk/klayout/lvs/)

• qpdk.lvs.j2 — Jinja2 template covering layer definitions, connectivity (TSV, indium bumps, airbridges), marker-based device extraction, and port/pin detection
• render_lvs.py — Declarative data tables for layers, connectivity rules, and device definitions; renders the template
• qpdk.lvs — Generated deck, invoked as:

klayout -b -r qpdk/klayout/lvs/qpdk.lvs \
    -rd input=layout.gds \
    -rd schematic=netlist.cir \
    -rd report=lvs_report.lvsdb

Adding a new device type requires only appending to the DEVICES list in render_lvs.py and re-rendering.

Documentation (docs/lvs.md)

Covers what LVS is in the quantum context, how the deck works (connectivity, ports, markers), how to add port/marker shapes to components, how to run LVS, and how to inspect results in KLayout's Netlist Database Browser.

Tests (tests/test_lvs.py)

9 tests covering template rendering, layer/connectivity/device coverage, and committed file consistency.

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[Copilot]

Pull request overview

Adds an LVS (layout-vs-schematic) flow to QPDK using KLayout, including a generated LVS deck (via Jinja2 templating), new LVS-specific layers (ports + device markers), documentation for running/inspecting LVS, and a small test suite to keep the generated deck in sync.

Changes:

• Introduces a Jinja2-templated KLayout LVS deck plus a Python renderer and committed generated output.
• Adds LVS port layers and device marker layers to the PDK layer map and layer-view configuration (YAML + KLayout layer properties).
• Adds documentation and tests for the rendering/deck consistency.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tests/test_lvs.py	New tests asserting renderer output coverage and that the committed deck matches rendering.
qpdk/tech.py	Adds PORT_* and MK_* layer constants to the PDK layer map.
qpdk/layers.yaml	Adds LVS_Ports and LVS_Markers layer-view groups for visibility/coloring.
qpdk/klayout/tech.lyt	Reorders connectivity <symbols> entries (no functional changes apparent).
qpdk/klayout/lvs/render_lvs.py	New deck renderer with declarative layer/connectivity/device tables.
qpdk/klayout/lvs/qpdk.lvs.j2	New Jinja2 template for the KLayout LVS deck.
qpdk/klayout/lvs/qpdk.lvs	Generated LVS deck committed to the repo.
qpdk/klayout/layers.lyp	Adds LVS port/marker groups to the KLayout layer properties file.
docs/lvs.md	New end-to-end documentation for the LVS flow, including component authoring guidance.
docs/index.md	Adds LVS docs page to the docs toctree under “Verification”.

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[Copilot]

from qpdk.klayout.lvs ... will fail because qpdk/klayout/ and qpdk/klayout/lvs/ are not Python packages in this repo (no __init__.py files). Add __init__.py files (or move the renderer into an existing package) so these imports and tests can run.

Suggested change

	from qpdk.klayout.lvs import render_lvs as _render_lvs_mod
	from qpdk.klayout.lvs.render_lvs import (
	CONNECTIONS,
	DEVICES,
	MARKER_LAYERS,
	PHYSICAL_LAYERS,
	PORT_LAYERS,
	render,
	)
	from importlib.machinery import SourceFileLoader
	from pathlib import Path
	_render_lvs_path = (
	Path(__file__).resolve().parents[1]
	/ "qpdk"
	/ "klayout"
	/ "lvs"
	/ "render_lvs.py"
	)
	_render_lvs_mod = SourceFileLoader(
	"qpdk_klayout_lvs_render_lvs", str(_render_lvs_path)
	).load_module()
	CONNECTIONS = _render_lvs_mod.CONNECTIONS
	DEVICES = _render_lvs_mod.DEVICES
	MARKER_LAYERS = _render_lvs_mod.MARKER_LAYERS
	PHYSICAL_LAYERS = _render_lvs_mod.PHYSICAL_LAYERS
	PORT_LAYERS = _render_lvs_mod.PORT_LAYERS
	render = _render_lvs_mod.render

[Copilot]

render_lvs.py imports jinja2, but jinja2 is not listed in the project’s core or test dependencies (it appears only under the docs dependency group). Since this module is imported by tests and is part of the shipped package, add jinja2 to the appropriate runtime deps (or make this import optional / guarded) to avoid ImportError in CI and user installs.

Suggested change

	from jinja2 import Environment, FileSystemLoader
	try:
	from jinja2 import Environment, FileSystemLoader
	except ImportError: # pragma: no cover - exercised only when jinja2 is missing
	def _missing_jinja2(*args: object, **kwargs: object) -> "NoReturn": # type: ignore[name-defined]
	raise RuntimeError(
	"The 'jinja2' package is required to use qpdk.klayout.lvs.render_lvs. "
	"Install it as a runtime dependency (e.g. 'pip install jinja2') or via "
	"the appropriate extras group for this project."
	)
	Environment = _missing_jinja2 # type: ignore[assignment]
	FileSystemLoader = _missing_jinja2 # type: ignore[assignment]

[Copilot]

Importing logger via from qpdk import logger executes qpdk/__init__.py (which constructs the PDK and imports gdsfactory), adding unnecessary side effects and startup cost for a simple deck renderer. Prefer importing the logger directly (e.g., from qpdk.logger import logger) to keep this script lightweight.

Suggested change

	from qpdk import logger
	from qpdk.logger import logger

[Copilot]

The module docstring says the deck is rendered “using the layer and device definitions from qpdk.tech”, but the layer/connectivity/device tables are currently hard-coded in this file. Either source these values from qpdk.tech (to prevent drift) or adjust the docstring to match the implementation.

Suggested change

	``qpdk.lvs`` using the layer and device definitions from :mod:`qpdk.tech`.
	``qpdk.lvs`` using the layer and device definitions defined in this module.

[Copilot]

In this example, bbox = c.bbox() is treated like a 2×2 array (bbox[0][0], etc.), but elsewhere in this repo bbox() returns a KLayout box-like object with attributes (left/right/top/bottom or p1/p2). As written, this snippet is likely to raise at runtime; update it to use the box attributes used throughout the codebase.

Suggested change

	(bbox[0][0], bbox[0][1]),
	(bbox[1][0], bbox[0][1]),
	(bbox[1][0], bbox[1][1]),
	(bbox[0][0], bbox[1][1]),
	(bbox.left, bbox.bottom),
	(bbox.right, bbox.bottom),
	(bbox.right, bbox.top),
	(bbox.left, bbox.top),