janik
06c62e04f8
DC/AC resistance, power dissipation, and via/injection-area currents of copper zone fills. KiCad 10 IPC-API plugin (kicad-python/kipy): multi-layer via-coupled FDM solver, multi-part terminals via User.1/User.2 marker layers, pads as contacts, uniform-injection and equipotential contact models, per-foil skin effect, optional solder/copper buildup on mask openings. 54-case test suite incl. exact analytic references. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
481 lines
18 KiB
Python
481 lines
18 KiB
Python
"""All KiCad IPC access. This is the ONLY module that imports kipy;
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everything downstream works on plain geometry dataclasses.
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Run `python -m fill_resistance.board_io dump.json [net]` against a live
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KiCad to extract without the dialog (all layers of the net, defaults).
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"""
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from __future__ import annotations
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from dataclasses import dataclass, field
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from pathlib import Path
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from kipy import KiCad
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from kipy.board import Board
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from kipy.board_types import BoardRectangle, Pad
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from kipy.proto.board.board_pb2 import BoardStackupLayerType
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from kipy.proto.board.board_types_pb2 import ZoneType
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from kipy.util.board_layer import (canonical_name, is_copper_layer,
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layer_from_canonical_name)
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from . import config
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from .errors import ApiVersionError, CandidateError, SelectionError
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from .geometry import (Electrode, LayerFill, Polygon, Problem, Rect,
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SurfaceBuildup, ViaLink, linearize_ring)
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MASK_TO_COPPER = {"F.Mask": "F.Cu", "B.Mask": "B.Cu"}
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# zone fills are polygonal in practice; tolerance only guards arc nodes
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ARC_TOL_NM = 10_000
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def connect() -> tuple[KiCad, Board]:
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try:
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kicad = KiCad()
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kicad.ping()
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except Exception as e:
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raise ApiVersionError(
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f"Could not connect to KiCad's IPC API: {e}\n"
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f"Is KiCad running with the API server enabled "
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f"(Preferences > Plugins > Enable KiCad API)?"
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)
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try:
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print(f"connected to KiCad {kicad.get_version()}")
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except Exception:
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pass
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try:
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board = kicad.get_board()
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except Exception as e:
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raise SelectionError(
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f"Could not get the open board from KiCad: {e}\n"
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f"Open the PCB in the board editor and run again."
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)
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return kicad, board
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def board_dir(board: Board) -> Path:
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# document.board_filename is a bare file name (no directory) in
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# KiCad 10.0.1; the project path is the reliable location
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try:
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path = board.get_project().path
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if path and Path(path).is_dir():
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return Path(path)
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except Exception:
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pass
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try:
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filename = getattr(board.document, "board_filename", "") or ""
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if Path(filename).is_absolute():
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return Path(filename).parent
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except Exception:
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pass
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return Path.cwd()
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# --- stackup geometry --------------------------------------------------------
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@dataclass
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class StackupInfo:
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names: list[str] # copper layers, top to bottom
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thickness_nm: dict[str, int]
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z_nm: dict[str, int] # copper center depth
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z_bot_nm: int # total stack thickness
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def get_stackup_info(board: Board) -> StackupInfo:
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names: list[str] = []
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thickness: dict[str, int] = {}
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z_center: dict[str, int] = {}
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z = 0
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for sl in board.get_stackup().layers:
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t = int(sl.thickness or 0)
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if sl.type == BoardStackupLayerType.BSLT_COPPER:
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name = canonical_name(sl.layer)
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if t <= 0:
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t = int(config.FALLBACK_THICKNESS_UM * 1000)
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print(f"warning: stackup gives no thickness for {name}; "
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f"assuming {config.FALLBACK_THICKNESS_UM} um")
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names.append(name)
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thickness[name] = t
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z_center[name] = z + t // 2
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z += t
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if not names:
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raise CandidateError(
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"Could not read any copper layer from the board stackup."
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)
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return StackupInfo(names=names, thickness_nm=thickness, z_nm=z_center,
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z_bot_nm=z)
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# --- electrodes from selection ----------------------------------------------
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def _box2_to_rect(box, layer_name: str) -> Rect:
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try:
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pos, size = box.pos, box.size
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return Rect.normalized(pos.x, pos.y, pos.x + size.x, pos.y + size.y,
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layer_name)
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except AttributeError:
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c, s = box.center, box.size
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return Rect.normalized(c.x - s.x // 2, c.y - s.y // 2,
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c.x + s.x // 2, c.y + s.y // 2, layer_name)
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def _convert_poly(poly_with_holes) -> Polygon:
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def ring(polyline):
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nodes = []
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for node in polyline.nodes:
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if node.has_point:
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nodes.append(("pt", (node.point.x, node.point.y)))
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elif node.has_arc:
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arc = node.arc
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nodes.append(("arc", ((arc.start.x, arc.start.y),
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(arc.mid.x, arc.mid.y),
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(arc.end.x, arc.end.y))))
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return linearize_ring(nodes, ARC_TOL_NM)
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return Polygon(outline=ring(poly_with_holes.outline),
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holes=[ring(h) for h in poly_with_holes.holes])
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def _pad_drill_nm(pad_or_via) -> int:
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try:
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return int(pad_or_via.padstack.drill.diameter.x)
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except Exception:
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return 0
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def _pad_default_contact(pad: Pad) -> str:
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if _pad_drill_nm(pad) > 0:
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return "all" # through-hole: contacts the stack
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try:
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copper = [canonical_name(l) for l in pad.padstack.layers
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if is_copper_layer(l)]
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if len(copper) == 1:
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return copper[0] # SMD: its own layer
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except Exception:
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pass
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return "all"
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def _pad_polygons(board: Board, pad: Pad, contact: str) -> list[Polygon] | None:
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layer_ids = []
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if contact != "all":
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try:
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layer_ids.append(layer_from_canonical_name(contact))
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except Exception:
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pass
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for name in ("F.Cu", "B.Cu"):
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try:
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layer_ids.append(layer_from_canonical_name(name))
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except Exception:
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pass
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for lid in layer_ids:
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try:
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shape = board.get_pad_shapes_as_polygons(pad, layer=lid)
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if shape is not None:
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return [_convert_poly(shape)]
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except Exception:
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continue
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return None
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def _to_electrode(board: Board, item) -> Electrode:
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if isinstance(item, BoardRectangle):
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tl, br = item.top_left, item.bottom_right
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rect = Rect.normalized(tl.x, tl.y, br.x, br.y,
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canonical_name(item.layer))
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cx = (rect.x0 + rect.x1) / 2e6
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cy = (rect.y0 + rect.y1) / 2e6
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return Electrode(rect=rect, contact="all",
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label=f"rect({cx:.1f},{cy:.1f})")
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# Pad
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pad: Pad = item
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contact = _pad_default_contact(pad)
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net = pad.net.name if pad.net is not None else "?"
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label = f"pad {pad.number}@{net}"
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box = board.get_item_bounding_box(pad)
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if box is None:
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raise SelectionError(f"Could not get the bounding box of {label}.")
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rect = _box2_to_rect(box, "pad")
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return Electrode(rect=rect, contact=contact,
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polygons=_pad_polygons(board, pad, contact), label=label)
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def _net_hint_of(pads: list[Pad]) -> str | None:
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for pad in pads:
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if pad.net is not None:
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return pad.net.name
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return None
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def get_electrodes(board: Board
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) -> tuple[list[Electrode], list[Electrode], str | None]:
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"""Terminals from the selection. Each terminal may have MULTIPLE parts
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(all merged into one externally-bonded contact):
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- rectangles on ELECTRODE_POS_LAYER -> V+ parts, on ELECTRODE_NEG_LAYER
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-> V- parts; selected pads fill a side that has no rectangles;
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- no marker rectangles selected: legacy mode, exactly 2 items
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(rects/pads, any layer) -> one part each;
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- empty selection: board-wide scan of both marker layers.
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"""
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pos_l = config.ELECTRODE_POS_LAYER
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neg_l = config.ELECTRODE_NEG_LAYER
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scheme = (f"Draw V+ rectangle(s) on {pos_l} and V- rectangle(s) on "
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f"{neg_l} (axis-aligned), and/or select pads for a side "
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f"without rectangles.")
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selection = list(board.get_selection())
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rects = [s for s in selection if isinstance(s, BoardRectangle)]
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pads = [s for s in selection if isinstance(s, Pad)]
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if not selection:
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allr = [s for s in board.get_shapes() if isinstance(s, BoardRectangle)]
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pos = [r for r in allr if canonical_name(r.layer) == pos_l]
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neg = [r for r in allr if canonical_name(r.layer) == neg_l]
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if pos and neg:
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print(f"selection empty - using {len(pos)} rectangle(s) on "
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f"{pos_l} as V+ and {len(neg)} on {neg_l} as V-")
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return ([_to_electrode(board, r) for r in pos],
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[_to_electrode(board, r) for r in neg], None)
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raise SelectionError(
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f"Nothing selected, and the board-wide scan found "
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f"{len(pos)} rectangle(s) on {pos_l} / {len(neg)} on {neg_l} "
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f"(need at least one on each).\n{scheme}"
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)
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pos = [r for r in rects if canonical_name(r.layer) == pos_l]
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neg = [r for r in rects if canonical_name(r.layer) == neg_l]
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other = [r for r in rects if canonical_name(r.layer) not in (pos_l, neg_l)]
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if pos or neg:
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if other:
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raise SelectionError(
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f"{len(other)} selected rectangle(s) are on neither marker "
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f"layer ({pos_l} = V+, {neg_l} = V-). {scheme}"
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)
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es1 = [_to_electrode(board, r) for r in pos]
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es2 = [_to_electrode(board, r) for r in neg]
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if pads and es1 and es2:
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raise SelectionError(
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f"Cannot assign the {len(pads)} selected pad(s): both marker "
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f"layers already provide rectangles. Use pads only for a "
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f"side that has none."
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)
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if pads:
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pad_parts = [_to_electrode(board, p) for p in pads]
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if not es1:
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es1 = pad_parts
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else:
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es2 = pad_parts
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if es1 and es2:
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return es1, es2, _net_hint_of(pads)
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raise SelectionError(
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f"Only one terminal defined: V+ has {len(es1)} and V- has "
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f"{len(es2)} contact(s). {scheme}"
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)
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items = rects + pads
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if len(items) == 2:
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return ([_to_electrode(board, items[0])],
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[_to_electrode(board, items[1])], _net_hint_of(pads))
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raise SelectionError(
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f"The selection has {len(rects)} rectangle(s) (none on the marker "
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f"layers) and {len(pads)} pad(s); without marker layers exactly 2 "
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f"contacts are needed.\n{scheme}"
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)
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# --- fills -------------------------------------------------------------------
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def gather_net_fills(board: Board) -> dict[str, dict[str, list[Polygon]]]:
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"""net -> layer_name -> merged fill polygons (non-empty only)."""
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fills: dict[str, dict[str, list[Polygon]]] = {}
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for zone in board.get_zones():
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if zone.type != ZoneType.ZT_COPPER:
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continue
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net = zone.net.name if zone.net is not None else "<no net>"
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for layer, polys in zone.filled_polygons.items():
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if not is_copper_layer(layer) or not polys:
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continue
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fills.setdefault(net, {}).setdefault(
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canonical_name(layer), []).extend(
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_convert_poly(p) for p in polys)
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return fills
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def _rect_overlaps(rect: Rect, polygons: list[Polygon]) -> bool:
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for p in polygons:
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px0, py0 = p.outline.min(axis=0)
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px1, py1 = p.outline.max(axis=0)
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if rect.x0 <= px1 and rect.x1 >= px0 and rect.y0 <= py1 and rect.y1 >= py0:
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return True
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return False
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def nets_overlapping(fills: dict, es1: list[Electrode],
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es2: list[Electrode]) -> list[str]:
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"""Nets whose fills overlap both terminals (any part, any layer each -
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the connection may go through vias). Permissive bbox prefilter."""
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out = []
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for net, per_layer in fills.items():
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hit1 = any(_rect_overlaps(e.rect, polys) for e in es1
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for polys in per_layer.values())
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hit2 = any(_rect_overlaps(e.rect, polys) for e in es2
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for polys in per_layer.values())
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if hit1 and hit2:
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out.append(net)
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return sorted(out)
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def gather_mask_buildups(board: Board) -> dict[str, list[Polygon]]:
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"""Zones on F.Mask/B.Mask (mask openings) -> fill polygons keyed by
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the outer copper layer they expose."""
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out: dict[str, list[Polygon]] = {}
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for zone in board.get_zones():
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try:
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filled = zone.filled_polygons
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except Exception:
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continue
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for layer, polys in filled.items():
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copper = MASK_TO_COPPER.get(canonical_name(layer))
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if copper and polys:
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out.setdefault(copper, []).extend(
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_convert_poly(p) for p in polys)
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return out
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def any_zone_unfilled(board: Board) -> bool:
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return any(z.type == ZoneType.ZT_COPPER and not z.filled
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for z in board.get_zones())
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def refill(board: Board) -> None:
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print("refilling zones - this modifies the open document ...")
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board.refill_zones(block=True)
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# --- barrels -----------------------------------------------------------------
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def _padstack_span(padstack, stackup: StackupInfo) -> tuple[int, int]:
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"""(z_top, z_bot) of the barrel; falls back to the full stack."""
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try:
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copper = [canonical_name(l) for l in padstack.layers
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if is_copper_layer(l)]
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zs = [stackup.z_nm[c] for c in copper if c in stackup.z_nm]
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if len(zs) >= 2:
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return min(zs) - 1, max(zs) + 1
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except Exception:
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pass
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return -1, stackup.z_bot_nm + 1
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def gather_barrels(board: Board, net_name: str,
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stackup: StackupInfo) -> list[ViaLink]:
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barrels = []
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for via in board.get_vias():
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if via.net is None or via.net.name != net_name:
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continue
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drill = int(via.drill_diameter or 0) or _pad_drill_nm(via)
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if drill <= 0:
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continue
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z_top, z_bot = _padstack_span(via.padstack, stackup)
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barrels.append(ViaLink(x=via.position.x, y=via.position.y,
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drill_nm=drill, z_top_nm=z_top,
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z_bot_nm=z_bot, kind="via"))
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if config.INCLUDE_TH_PADS:
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for pad in board.get_pads():
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if pad.net is None or pad.net.name != net_name:
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continue
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drill = _pad_drill_nm(pad)
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if drill <= 0:
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continue
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barrels.append(ViaLink(x=pad.position.x, y=pad.position.y,
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drill_nm=drill, z_top_nm=-1,
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z_bot_nm=stackup.z_bot_nm + 1, kind="pad"))
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return barrels
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# --- top level ----------------------------------------------------------------
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def build_problem(board: Board, net: str, layer_names: list[str],
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es1: list[Electrode], es2: list[Electrode],
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stackup: StackupInfo, fills: dict,
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buildups: dict[str, list[Polygon]] | None = None,
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extra_cu_um: float | None = None) -> Problem:
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per_layer = fills.get(net, {})
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layers = []
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for name in stackup.names: # keep stackup order
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if name not in layer_names:
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continue
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polys = per_layer.get(name, [])
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if not polys:
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print(f"note: net {net} has no fill on {name} - layer skipped")
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continue
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if config.COPPER_THICKNESS_UM is not None:
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t, source = int(config.COPPER_THICKNESS_UM * 1000), "override"
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else:
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t, source = stackup.thickness_nm[name], "stackup"
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layers.append(LayerFill(layer_name=name, thickness_nm=t,
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z_nm=stackup.z_nm[name], polygons=polys))
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if not layers:
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raise CandidateError(
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f"Net {net} has no fill on any of the selected layers "
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f"({', '.join(layer_names)})."
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)
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vias = gather_barrels(board, net, stackup) if len(layers) > 1 else []
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included = {l.layer_name for l in layers}
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buildup_list = [
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SurfaceBuildup(layer_name=name, polygons=polys)
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for name, polys in (buildups or {}).items() if name in included
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]
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print(f"net {net}: {len(layers)} layer(s) "
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f"({', '.join(l.layer_name for l in layers)}), "
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f"{len(vias)} via/pad barrel(s)"
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+ (f", solder buildup on "
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f"{', '.join(b.layer_name for b in buildup_list)}"
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if buildup_list else ""))
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return Problem(
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board_path=board.name or "",
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net_name=net,
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rho_ohm_m=config.RHO_CU_OHM_M,
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plating_nm=int(config.VIA_PLATING_UM * 1000),
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layers=layers,
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vias=vias,
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electrodes1=es1,
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electrodes2=es2,
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thickness_source=("override" if config.COPPER_THICKNESS_UM is not None
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else "stackup"),
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buildups=buildup_list,
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solder_thickness_nm=int(config.SOLDER_THICKNESS_UM * 1000),
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solder_rho_ohm_m=config.SOLDER_RHO_OHM_M,
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extra_cu_nm=int((extra_cu_um if extra_cu_um is not None
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else config.BUILDUP_EXTRA_CU_UM) * 1000),
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)
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if __name__ == "__main__":
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import sys
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from .geometry import save_problem
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out = Path(sys.argv[1]) if len(sys.argv) > 1 else Path("geometry_dump.json")
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_, board = connect()
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stackup = get_stackup_info(board)
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es1, es2, net_hint = get_electrodes(board)
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if any_zone_unfilled(board):
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refill(board)
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fills = gather_net_fills(board)
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nets = nets_overlapping(fills, es1, es2)
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if len(sys.argv) > 2:
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net = sys.argv[2]
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elif net_hint in nets:
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net = net_hint
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elif len(nets) == 1:
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net = nets[0]
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else:
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print(f"candidate nets: {nets}; pass one as second argument")
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sys.exit(1)
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problem = build_problem(board, net, list(fills.get(net, {})), es1, es2,
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stackup, fills)
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save_problem(problem, out)
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print(f"wrote {out}")
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