Files
rpmroute/src/freeroute/route/grid_router.py
T
rsp2k 245cd91c0e Don't cost a pin stub for a route that ends on a plane
A plane end is marked with its zone, not a pin, so a route from a pad
outside the plane's outline crashed looking for the pin's location
(the flight-controller board's first placement).
2026-09-28 19:55:07 -06:00

1256 lines
55 KiB
Python

"""A grid-based maze router (MVP): multi-layer, vias, and rip-up-and-retry.
Still an *MVP* — not a port of FreeRouting's expansion-room maze / ripper — but
it routes across the board's signal layers, changes layers through vias, and
recovers from bad greedy net orderings with rip-up-and-retry:
* the occupancy grid has a layer axis; A* nodes are ``(col, row, layer)``;
* in-plane moves (8-connected, 45-degree) cost distance; a **via move** changes
layer at a cell for a configurable ``via_cost``; a through via must be clear on
every signal layer;
* occupancy is tracked *per connection* so a specific routed connection can be
removed. When a connection cannot reach its target through free space, the
router runs a **rip-up** search that may pass through other nets' traces (at a
penalty), rips up the connections it crosses, routes the failing connection,
and re-queues the ripped connections for a later pass;
* passes iterate up to ``max_passes``, keeping the best (fewest-unrouted) result
and stopping on full success or when a pass changes nothing;
* **thrash prevention:** each connection may be ripped at most ``rip_cap`` times,
and the penalty to rip a connection escalates with its rip count, so
repeatedly-ripped connections harden into walls. Everything is deterministic
(no RNG).
Deferred (still): FreeRouting's free-space expansion rooms, exact shove /
DRC-clean geometry, and blind/buried via spans.
"""
from __future__ import annotations
import heapq
import math
import random
from freeroute.board.board import BasicBoard
from freeroute.board.items import ConductionArea, ObstacleArea, Pin
from freeroute.geometry import IntBox, IntPoint
from freeroute.geometry.polyline import corner_box
__all__ = ["GridRouter", "RouteResult", "route_board"]
# 8-connected in-plane neighbourhood (orthogonal + diagonal) for 45-degree routing.
_NEIGHBOURS = [
(1, 0),
(-1, 0),
(0, 1),
(0, -1),
(1, 1),
(1, -1),
(-1, 1),
(-1, -1),
]
Cell = tuple[int, int]
Node = tuple[int, int, int] # (col, row, layer)
class RouteResult:
"""Per-net routing outcome in *board* units.
``wires`` maps a net number to a list of ``(layer_index, [IntPoint, ...])``
trace segments; ``vias`` maps a net number to a list of via locations.
``routed_net_numbers`` are the nets that got any wire or via.
"""
__slots__ = ("wires", "vias", "half_width", "unrouted", "connections", "connection_ends", "failed")
def __init__(self, half_width: int) -> None:
self.wires: dict[int, list[tuple[int, list[IntPoint]]]] = {}
self.vias: dict[int, list[IntPoint]] = {}
self.half_width = half_width
#: number of ratsnest connections left unrouted
self.unrouted = 0
#: the same copper per routed connection: (net_no, wires, vias)
self.connections: list[tuple[int, list[tuple[int, list[IntPoint]]], list[IntPoint]]] = []
#: what each routed connection joins, and the zone both ends sit in
#: (or ""), parallel to ``connections``
self.connection_ends: list[tuple[str, str, str]] = []
#: connections left unrouted: (net_no, one end, the other end)
self.failed: list[tuple[int, str, str]] = []
def add_wire(self, net_no: int, layer: int, path: list[IntPoint]) -> None:
self.wires.setdefault(net_no, []).append((layer, path))
def add_via(self, net_no: int, location: IntPoint) -> None:
self.vias.setdefault(net_no, []).append(location)
@property
def routed_net_numbers(self) -> set[int]:
nets = {n for n, w in self.wires.items() if w}
nets |= {n for n, v in self.vias.items() if v}
return nets
def via_count(self) -> int:
return sum(len(v) for v in self.vias.values())
class _Connection:
"""One ratsnest connection (a pin pair) and its routed state."""
__slots__ = (
"index",
"net_no",
"a",
"b",
"routed",
"rip_count",
"wires",
"vias",
"trace_cells",
"via_cells",
"via_halo",
"halo_nodes",
"a_group",
"b_group",
"a_end",
"b_end",
"path",
)
def __init__(self, index: int, net_no: int, a: Pin, b: Pin) -> None:
self.index = index
self.net_no = net_no
self.a = a
self.b = b
self.routed = False
self.rip_count = 0
self.wires: list[tuple[int, list[IntPoint]]] = []
self.vias: list[IntPoint] = []
self.trace_cells: list[tuple[Cell, int]] = []
self.via_cells: list[Cell] = []
self.via_halo: list[Cell] = []
self.halo_nodes: list[Node] = []
# the pins and zones each end may use, and which pin the route ended
# on (None when it ended on a zone)
self.a_group: tuple[list[Pin], list] = ([a], [])
self.b_group: tuple[list[Pin], list] = ([b], [])
self.a_end: Pin | None = a
self.b_end: Pin | None = b
# the node path last committed, so a rip-up can be undone
self.path: list[Node] | None = None
class GridRouter:
"""Routes a :class:`BasicBoard` with a grid A*, vias, and rip-up-and-retry."""
def __init__(
self,
board: BasicBoard,
*,
trace_width: int,
clearance: int,
layers: list[int] | None = None,
via_cost: float = 10.0,
rip_up: bool = True,
max_passes: int = 10,
rip_cap: int = 4,
rip_penalty: float = 30.0,
orthogonal: bool = False,
via_half: int | None = None,
edge_clearance: int | None = None,
resolution: int = 1,
heuristic_weight: float = 1.0,
seed: int | None = None,
route_first: frozenset | None = None,
access_cost: float = 0.0,
rollback: bool = True,
) -> None:
self.board = board
# Pin access: while a pin still has connections to route, the cells
# its route would leave by (its end cells, the via it may need there,
# and the clearance around both) cost other nets this much extra, so
# they route round a fine-pitch pin's way out instead of sealing it.
self.access_cost = max(float(access_cost), 0.0)
self._doorways: dict[Node, list[tuple[int, int]]] = {}
self._pending: dict[int, int] = {}
# Rip-up as a transaction: the connections a rip-up route crosses are
# rerouted at once, and if fewer connections are routed afterwards
# than before, everything goes back as it was. On by default: over
# 8 net orders it left 25 to 30 fewer connections unrouted on dense
# boards and was never clearly worse.
self.rollback = bool(rollback)
# None keeps the deterministic order; a seed shuffles which connection
# routes first, to measure how much a result owes to the order
self.seed = seed
# connections, as (net_no, one end, other end), to route before the rest
self.route_first = frozenset(route_first or ())
# how far (in cells) an escape stub may run to leave a walled-in pin
self._escape_cells = 12
self._crowded_cache: dict = {}
self._trapped_cache: dict = {}
self.heuristic_weight = max(float(heuristic_weight), 1.0)
self.trace_width = max(trace_width, 1)
self.clearance = max(clearance, 0)
self.half_width = self.trace_width // 2
self.via_cost = via_cost
self.rip_up = rip_up
self.max_passes = max(max_passes, 1)
self.rip_cap = max(rip_cap, 0)
self.rip_penalty = rip_penalty
# orthogonal routing (axis-aligned segments only) yields exact IntBox
# trace copper; 8-connected also produces 45-degree segments.
self._neighbours = _NEIGHBOURS[:4] if orthogonal else _NEIGHBOURS
self._orthogonal = orthogonal
# At resolution 1 a cell is exactly one trace plus its clearance, so a
# trace owning its cell is the whole clearance model. At resolution k
# cells are k times finer, fine enough to give every pin of a 0.5 mm
# pitch row its own column, and a trace also claims a halo: the cells
# whose centre is nearer than trace + clearance to one of its own.
self.resolution = max(int(resolution), 1)
self.step = max((self.trace_width + self.clearance) // self.resolution, 1)
need = self.trace_width + self.clearance
reach = math.ceil(need / self.step)
self._halo_offsets = [
(dx, dy)
for dx in range(-reach, reach + 1)
for dy in range(-reach, reach + 1)
if (dx or dy) and math.hypot(dx, dy) * self.step < need
]
# A via's copper is wider than a trace. Another net's trace needs its
# centre via_half + clearance + half_width from the via's centre, so a
# via also claims every cell within via_reach of its own.
self.via_half = via_half or self.half_width
# copper to board edge; KiCad's rule is usually wider than clearance
self.edge_clearance = 0 if edge_clearance is None else edge_clearance
need = self.via_half + self.clearance + self.half_width
self.via_reach = max(0, math.ceil(need / self.step) - 1)
if layers is None:
layers = [i for i, layer in enumerate(board.layer_structure.arr) if layer.is_signal]
self.layers = list(layers)
box = board.bounding_box
self.origin_x = box.ll.x
self.origin_y = box.ll.y
self.cols = max(1, math.ceil((box.ur.x - box.ll.x) / self.step) + 1)
self.rows = max(1, math.ceil((box.ur.y - box.ll.y) / self.step) + 1)
# static obstacles
self._pad_block: dict[Node, set[int]] = {}
self._pad_own: dict[Node, set[int]] = {}
self._keepout: set[Node] = set()
self._via_keepout: set[Node] = set()
# inner power (plane) layers: not routed on, reached by vias
self._power_layers = {
i for i, layer in enumerate(board.layer_structure.arr) if not layer.is_signal
}
self._zone_cells: dict[int, list[Node]] = {}
# per-connection occupancy (owner = connection index)
self._cell_owner: dict[Node, int] = {}
self._via_owner: dict[Cell, int] = {}
# trace halos: node -> indices of the connections claiming it
self._halo: dict[Node, list[int]] = {}
self._rasterize_obstacles()
# --- grid helpers -------------------------------------------------------
def _cell_of(self, point: IntPoint) -> Cell:
gx = round((point.x - self.origin_x) / self.step)
gy = round((point.y - self.origin_y) / self.step)
gx = min(max(gx, 0), self.cols - 1)
gy = min(max(gy, 0), self.rows - 1)
return gx, gy
def _cell_center(self, cell: Cell) -> IntPoint:
return IntPoint(self.origin_x + cell[0] * self.step, self.origin_y + cell[1] * self.step)
def _cells_in_box(self, box, margin: int):
"""Cells whose centre lies strictly inside ``box`` grown by ``margin``.
A trace centred there would come closer than ``margin`` to the box.
Rounding the bounds outward instead blocked cells up to half a step
clear of it, which walled in every pin of a 0.5 mm pitch package.
"""
lo_x = math.floor((box.ll.x - margin - self.origin_x) / self.step) + 1
hi_x = math.ceil((box.ur.x + margin - self.origin_x) / self.step) - 1
lo_y = math.floor((box.ll.y - margin - self.origin_y) / self.step) + 1
hi_y = math.ceil((box.ur.y + margin - self.origin_y) / self.step) - 1
for gx in range(max(lo_x, 0), min(hi_x, self.cols - 1) + 1):
for gy in range(max(lo_y, 0), min(hi_y, self.rows - 1) + 1):
yield gx, gy
def _outline_blocked(self, reach: int) -> set[Cell]:
"""Cells whose centre is outside the outline or within ``reach`` of its edge."""
outline = self.board.outline
blocked: set[Cell] = set()
for gy in range(self.rows): # outside: one scanline per row
y = self.origin_y + gy * self.step
spans = outline.row_inside_spans(y)
for gx in range(self.cols):
x = self.origin_x + gx * self.step
if not any(lo < x < hi for lo, hi in spans):
blocked.add((gx, gy))
for a, b in outline.edges(): # too close: only cells near each edge
edge_box = IntBox(min(a.x, b.x), min(a.y, b.y), max(a.x, b.x), max(a.y, b.y))
for cell in self._cells_in_box(edge_box, reach):
if cell not in blocked and outline.edge_distance(self._cell_center(cell)) < reach:
blocked.add(cell)
return blocked
def _inside_own_pad(self, cell: Cell, shape) -> bool:
"""A trace centred on ``cell`` lies entirely on the pad's own copper."""
c = self._cell_center(cell)
h = self.half_width
return all(
shape.contains(IntPoint(c.x + dx, c.y + dy)) for dx in (-h, h) for dy in (-h, h)
)
def _rasterize_obstacles(self) -> None:
margin = self.clearance + self.half_width
outline = self.board.outline
self._via_edge_block: set[Cell] = set()
# wire keepouts as boxes, to check a pin stub the way the exact engine will
self._keepout_boxes: dict[int, list[tuple[IntBox, bool]]] = {}
# pin end nodes no wire can reach without entering a keepout
self._via_only: set[Node] = set()
if outline is not None:
# cells too close to the real outline (rounded corners included):
# for a trace on every layer, and separately for a via's wider copper
for cell in self._outline_blocked(self.half_width + self.edge_clearance):
for layer in self.layers:
self._keepout.add((*cell, layer))
self._via_edge_block = self._outline_blocked(self.via_half + self.edge_clearance)
for item in self.board.get_items():
if isinstance(item, Pin):
box = item.shape.bounding_box() if item.shape is not None else None
if box is None or box.is_empty():
continue
net = item.net_nos[0] if item.net_nos else 0
pin_layers = [layer for layer in item.layers if layer in self.layers]
for cell in self._cells_in_box(box, margin):
for layer in pin_layers:
self._pad_block.setdefault((*cell, layer), set()).add(net)
# Copper of the pin's own net: a trace inside it adds nothing,
# so it is open to that net however close the neighbours are.
# That is how a route leaves a fine-pitch pin.
for cell in self._cells_in_box(box, 0):
if self._inside_own_pad(cell, item.shape):
for layer in pin_layers:
self._pad_own.setdefault((*cell, layer), set()).add(net)
elif isinstance(item, ConductionArea):
continue # a zone is copper of its net, not an obstacle
elif isinstance(item, ObstacleArea):
if item.layer not in self.layers:
continue
# Tile by tile: the area's own bounding box of a ring (a
# no-track border along the board edge) is the whole board.
for tile in item.tiles:
box = tile.bounding_box()
if box.is_empty():
continue
# the same distance the exact engine verifies against
if item.blocks_wires:
self._keepout_boxes.setdefault(item.layer, []).append(
(box, item.clearance)
)
# a rule area takes no clearance: a trace may touch it
reach = margin if item.clearance else self.half_width
for cell in self._cells_in_box(box, reach):
if item.blocks_wires:
self._keepout.add((*cell, item.layer))
if item.blocks_vias:
self._via_keepout.add((*cell, item.layer))
# --- occupancy cost -----------------------------------------------------
def _enter_cost(
self,
cell: Cell,
layer: int,
net_no: int,
allow_ripup: bool,
conns: list[_Connection],
wire_keepout: bool = True,
) -> float | None:
"""Cost to enter ``(cell, layer)`` for ``net_no``; ``None`` if blocked.
Static pads/keepouts always block. A cell occupied by another net's trace
or via is impassable in free-space mode; in rip-up mode it is passable at
a penalty that escalates with the owner's rip count, unless the owner has
already hit ``rip_cap`` (then it hardens into a wall).
"""
node = (*cell, layer)
if wire_keepout and node in self._keepout:
return None
pads = self._pad_block.get(node)
if pads and any(n != net_no for n in pads) and net_no not in self._pad_own.get(node, ()):
return None
blocking = None
owner = self._cell_owner.get(node)
if owner is not None and conns[owner].net_no != net_no:
blocking = owner
else:
via_owner = self._via_owner.get(cell)
if via_owner is not None and conns[via_owner].net_no != net_no:
blocking = via_owner
if blocking is None:
for i in self._halo.get(node, ()):
if conns[i].net_no != net_no:
blocking = i
break
if blocking is None:
return 0.0
if not allow_ripup:
return None
rip_count = conns[blocking].rip_count
if rip_count >= self.rip_cap:
return None
return self.rip_penalty * (1 + rip_count)
def _via_cells(self, cell: Cell) -> list[Cell]:
"""The cell a via sits in plus the neighbours its copper reaches."""
r = self.via_reach
cx, cy = cell
return [
(x, y)
for x in range(max(cx - r, 0), min(cx + r, self.cols - 1) + 1)
for y in range(max(cy - r, 0), min(cy + r, self.rows - 1) + 1)
]
def _via_placeable(self, cell: Cell, net_no: int, conns: list[_Connection]) -> bool:
"""A through via needs its whole footprint free of other nets on every layer."""
if cell in self._via_edge_block:
return False
for c in self._via_cells(cell):
for layer in self.layers:
if (*c, layer) in self._via_keepout:
return False
if self._enter_cost(c, layer, net_no, False, conns, wire_keepout=False) != 0.0:
return False
return True
# --- A* search ----------------------------------------------------------
def _search(
self, conn: _Connection, allow_ripup: bool, conns: list[_Connection]
) -> list[Node] | None:
goal_cell = self._group_target(conn.b_group)
if not conn.b_group[0] and any(z.layer in self._power_layers for z in conn.b_group[1]):
# the plane is everywhere: aim at where the route starts instead
goal_cell = self._group_target(conn.a_group)
starts = self._group_ends(conn.a_group, conn.net_no, conns)
goals = self._group_ends(conn.b_group, conn.net_no, conns)
if not starts or not goals:
return None
common = sorted(set(starts) & set(goals))
if common:
conn.a_end, conn.b_end = starts[common[0]], goals[common[0]]
return [common[0]]
net_no = conn.net_no
open_heap: list[tuple[float, Node]] = []
g_score: dict[Node, float] = {}
came_from: dict[Node, Node] = {}
# a stub costs its length, so the nearest cell wins unless it is blocked
# a pin end costs its stub; a zone or plane end is entered normally
goal_stub = {n: self._stub_cost(p, n) for n, p in goals.items() if isinstance(p, Pin)}
for s in sorted(starts):
pin = starts[s]
g_score[s] = self._stub_cost(pin, s) if isinstance(pin, Pin) else 0.0
heapq.heappush(open_heap, (g_score[s] + self._h(s, goal_cell), s))
# Via footprints are checked lazily: a layer change goes on the heap as
# a candidate and is checked only if it is popped. Most never are (a
# via costs a lot), and the check is the single most expensive thing
# the search does. A check can only rule a via out, never make it
# cheaper, so deferring it cannot change which route is found.
via_ok: dict[Cell, bool] = {}
while open_heap:
entry = heapq.heappop(open_heap)
if len(entry) == 4: # a deferred via: (f, target, g, source)
_, target, g_via, source = entry
if g_via >= g_score.get(target, math.inf):
continue
cell = (target[0], target[1])
ok = via_ok.get(cell)
if ok is None:
ok = via_ok[cell] = self._via_placeable(cell, net_no, conns)
if ok:
self._relax(source, target, g_via, goal_cell, g_score, came_from, open_heap)
continue
current = entry[1]
if current in goals:
end = goals[current]
cell = (current[0], current[1])
if isinstance(end, ConductionArea): # a plane end needs its via to fit
ok = via_ok.get(cell)
if ok is None:
ok = via_ok[cell] = self._via_placeable(cell, net_no, conns)
else:
ok = True
if ok:
path = _reconstruct(came_from, current)
conn.a_end, conn.b_end = starts.get(path[0]), end
return path
cx, cy, cl = current
base = g_score[current]
# A cell inside a wire keepout (a pin there, or where a via
# landed) may only be left by another via: a wire from it would
# start inside the keepout.
blocked = current in self._keepout or current in self._via_only
neighbours = () if blocked else self._neighbours
for dx, dy in neighbours:
cell = (cx + dx, cy + dy)
if not (0 <= cell[0] < self.cols and 0 <= cell[1] < self.rows):
continue
nxt = (*cell, cl)
if nxt in goal_stub: # a pin end; a zone end is entered normally
if nxt in self._keepout or nxt in self._via_only:
continue # a pin inside a keepout is reached by a via only
enter = goal_stub[nxt]
else:
enter = self._enter_cost(cell, cl, net_no, allow_ripup, conns)
if enter is None:
continue
if self._doorways:
enter += self._access(nxt, net_no)
step = 1.0 if dx == 0 or dy == 0 else math.sqrt(2)
self._relax(
current, nxt, base + step + enter, goal_cell, g_score, came_from, open_heap
)
if len(self.layers) > 1:
g_via = base + self.via_cost
if self._doorways:
g_via += self._access(current, net_no)
for layer in self.layers:
if layer == cl:
continue
nxt = (cx, cy, layer)
if g_via < g_score.get(nxt, math.inf):
heapq.heappush(
open_heap, (g_via + self._h(nxt, goal_cell), nxt, g_via, current)
)
return None
# --- pin stubs ----------------------------------------------------------
# A pin rarely sits on a cell centre, so every route starts and ends with a
# short stub from the pin to its first cell. The grid has to see that
# copper too, or a stub ends up closer than clearance to a trace in the
# cell beside it.
def _stub_cells(self, pin_location: IntPoint, cell: Cell) -> list[Cell]:
"""Cells where another net's trace would come too close to the stub."""
from freeroute.board.outline import _point_segment
end = self._cell_center(cell)
reach = 2 * self.half_width + self.clearance
box = IntBox(
min(pin_location.x, end.x), min(pin_location.y, end.y),
max(pin_location.x, end.x), max(pin_location.y, end.y),
)
return [
c
for c in self._cells_in_box(box, reach)
if _point_segment(self._cell_center(c), pin_location, end) < reach
]
def _stub_clear(
self, pin: Pin, cell: Cell, layer: int, net_no: int, conns, keepouts_only: bool = False
) -> bool:
keepouts = self._keepout_boxes.get(layer)
if keepouts:
# the stub is off the grid, so check it exactly, as the exact
# engine will: its copper grown by clearance must miss every keepout
from freeroute.geometry.polyline import Polyline, PolylineShape
end = self._cell_center(cell)
if end != pin.location:
for tile in PolylineShape(Polyline([pin.location, end]), self.half_width).tiles():
grown = tile.offset(self.clearance)
if any(k.overlaps(grown if needs else tile) for k, needs in keepouts):
return False
# the track's round end at the pin, for a rule area
cap = corner_box(pin.location, self.half_width)
if any(not needs and k.overlaps(cap) for k, needs in keepouts):
return False
if keepouts_only:
return True
for c in self._stub_cells(pin.location, cell):
owner = self._cell_owner.get((*c, layer))
if owner is not None and conns[owner].net_no != net_no:
return False
via_owner = self._via_owner.get(c)
if via_owner is not None and conns[via_owner].net_no != net_no:
return False
return True
def _zone_nodes(self, zone) -> list[Node]:
"""Cells of a zone where a via of this net fits inside its copper; for a
plane on a power layer, on every routing layer (a via reaches it)."""
key = id(zone)
if key not in self._zone_cells:
h = self.via_half
layers = [zone.layer] if zone.layer in self.layers else list(self.layers)
nodes = []
for tile in zone.tiles:
for cell in self._cells_in_box(tile.bounding_box(), 0):
c = self._cell_center(cell)
if all(
zone.polygon.contains(IntPoint(c.x + dx, c.y + dy))
for dx in (-h, h) for dy in (-h, h)
):
nodes.extend((*cell, layer) for layer in layers)
self._zone_cells[key] = sorted(set(nodes))
return self._zone_cells[key]
def _zone_is_solid(self, zone, coverage: float = 0.95) -> bool:
"""Whether a zone's fill can be trusted to be one piece of copper.
A zone outline is where copper may go, not where it will be: other
nets' tracks through a board-wide pour break its fill into islands,
and a pad inside the outline need not reach the rest of the net. It
is safe to count on only when no track can cross it, which is what a
no-tracks rule area over the zone guarantees (the rc4 power pours).
Otherwise the zone is left out and its pads are routed with tracks.
"""
cells = [cell for tile in zone.tiles for cell in self._cells_in_box(tile.bounding_box(), 0)
if zone.polygon.contains(self._cell_center(cell))]
if not cells:
return False
covered = sum((*cell, zone.layer) in self._keepout for cell in cells)
return covered >= coverage * len(cells)
def _left_to_zone(self, conn) -> str:
"""The zone both ends of an unrouted connection sit in, if any: its
fill may well join them, even when it is not trusted for routing."""
for zone in self._every_zone_by_net.get(conn.net_no, []):
if any(_pin_touches_zone(p, zone) for p in conn.a_group[0]) and any(
_pin_touches_zone(p, zone) for p in conn.b_group[0]
):
return zone.name or "zone"
return ""
def _group_ends(self, group, net_no: int, conns) -> dict[Node, Pin | None]:
"""End nodes of a group, each mapped to its pin (None for a zone cell)."""
ends: dict[Node, Pin | None] = {}
for pin in group[0]:
for node in sorted(self._end_nodes(pin, net_no, conns)):
ends.setdefault(node, pin)
for zone in group[1]:
plane = zone.layer in self._power_layers
for node in self._zone_nodes(zone):
# a plane end is marked with the plane: the route ends in a via
ends.setdefault(node, zone if plane else None)
return ends
def _group_target(self, group) -> Cell:
if group[0]:
return self._cell_of(group[0][0].location)
box = group[1][0].bounding_box()
return self._cell_of(IntPoint((box.ll.x + box.ur.x) // 2, (box.ll.y + box.ur.y) // 2))
def _stub_cost(self, pin: Pin, node: Node) -> float:
c = self._cell_center(node[:2])
dx, dy = abs(c.x - pin.location.x), abs(c.y - pin.location.y)
if self._orthogonal: # measured the way the route itself is allowed to move
return (dx + dy) / self.step
return math.hypot(dx, dy) / self.step
def _end_nodes(self, pin: Pin, net_no: int, conns) -> set[Node]:
"""Nodes a route may start or end on for ``pin``: the nearest cell and
its neighbours, where the cell is enterable and the stub to it is clear.
A crowded fine-pitch pin gets more than one way out."""
layers = [layer for layer in pin.layers if layer in self.layers]
cx, cy = self._cell_of(pin.location)
nodes: set[Node] = set()
for dx, dy in ((0, 0), *self._neighbours):
cell = (cx + dx, cy + dy)
if not (0 <= cell[0] < self.cols and 0 <= cell[1] < self.rows):
continue
for layer in layers:
if (dx or dy) and self._enter_cost(cell, layer, net_no, False, conns) is None:
continue
if self._stub_clear(pin, cell, layer, net_no, conns):
nodes.add((*cell, layer))
# Also offer exact escape stubs: a fine-pitch pin's nearby cells can be
# a pocket inside its own pad that leads nowhere (the grid columns miss
# the narrow legal band past the pad tip). The stub's length is its
# cost, so it is only taken where a short step would not do.
if self._orthogonal and self._crowded(pin, net_no) and self._trapped(pin, net_no, nodes):
nodes |= self._escape_nodes(pin, net_no, conns, layers, (cx, cy))
if not nodes: # nothing clear: fall back to the nearest cell, as before
nodes = {(cx, cy, layer) for layer in layers}
if self._keepout_boxes and not any(
self._stub_clear(pin, (cx, cy), layer, net_no, conns, keepouts_only=True)
for layer in layers
):
# no wire can reach the pin without entering a keepout: the
# route has to arrive by a via, which goes in the pad
self._via_only.update(nodes)
return nodes
def _crowded(self, pin: Pin, net_no: int) -> bool:
"""A pin whose neighbour pad of another net is too close for a trace
to pass between them: a fine-pitch pin, the case escapes are for."""
key = (id(pin), net_no)
cached = self._crowded_cache.get(key)
if cached is not None:
return cached
box = pin.shape.bounding_box() if pin.shape is not None else None
gap = self.trace_width + 2 * self.clearance
crowded = False
if box is not None:
for other in self.board.get_pins():
if other is pin or net_no in other.net_nos or other.shape is None:
continue
if not set(other.layers) & set(pin.layers):
continue
ob = other.shape.bounding_box()
dx = max(ob.ll.x - box.ur.x, box.ll.x - ob.ur.x, 0)
dy = max(ob.ll.y - box.ur.y, box.ll.y - ob.ur.y, 0)
if max(dx, dy) < gap and min(dx, dy) == 0:
crowded = True
break
self._crowded_cache[key] = crowded
return crowded
def _static_open(self, node: Node, net_no: int) -> bool:
"""Open to ``net_no`` as far as pads and keepouts go (routes ignored)."""
if node in self._keepout:
return False
pads = self._pad_block.get(node)
return not (pads and any(n != net_no for n in pads) and net_no not in self._pad_own.get(node, ()))
def _trapped(self, pin: Pin, net_no: int, nodes: set[Node], limit: int = 60) -> bool:
"""Whether a pin's nearby cells are a dead-end pocket, judged against
pads and keepouts only (not other routes), so it is fixed per pin."""
key = (id(pin), net_no)
cached = self._trapped_cache.get(key)
if cached is not None:
return cached
seen = set(nodes)
frontier = list(nodes)
while frontier and len(seen) < limit:
x, y, layer = frontier.pop()
for dx, dy in self._neighbours:
n = (x + dx, y + dy, layer)
if n in seen or not (0 <= n[0] < self.cols and 0 <= n[1] < self.rows):
continue
if self._static_open(n, net_no):
seen.add(n)
frontier.append(n)
trapped = len(seen) < limit
self._trapped_cache[key] = trapped
return trapped
def _escape_nodes(self, pin: Pin, net_no: int, conns, layers, origin: Cell) -> set[Node]:
"""For a pin walled in on the grid (a fine-pitch pin whose legal band
the grid columns miss): look along each axis for the first open cell
whose straight stub from the pin clears every other net's pad by the
full margin, measured exactly rather than on the grid."""
from freeroute.board.outline import _segment_box
margin = self.half_width + self.clearance
reach = self._escape_cells
near = [
(p.shape.bounding_box(), set(p.layers))
for p in self.board.get_pins()
if p.shape is not None
and net_no not in p.net_nos
and abs(p.location.x - pin.location.x) < (reach + 2) * self.step * 2
and abs(p.location.y - pin.location.y) < (reach + 2) * self.step * 2
]
cx, cy = origin
nodes: set[Node] = set()
for dx, dy in _NEIGHBOURS[:4]:
for k in range(2, reach + 1):
cell = (cx + dx * k, cy + dy * k)
if not (0 <= cell[0] < self.cols and 0 <= cell[1] < self.rows):
break
end = self._cell_center(cell)
for layer in layers:
if self._enter_cost(cell, layer, net_no, False, conns) is None:
continue
if any(
layer in box_layers and _segment_box(pin.location, end, box) < margin
for box, box_layers in near
):
continue
if self._stub_clear(pin, cell, layer, net_no, conns):
nodes.add((*cell, layer))
if any(n[:2] == cell for n in nodes):
break # the first open cell along this axis is enough
return nodes
def _relax(self, current, nxt, tentative, goal_cell, g_score, came_from, open_heap):
if tentative < g_score.get(nxt, math.inf):
came_from[nxt] = current
g_score[nxt] = tentative
heapq.heappush(open_heap, (tentative + self._h(nxt, goal_cell), nxt))
def _h(self, node: Node, goal_cell: Cell) -> float:
dx, dy = abs(node[0] - goal_cell[0]), abs(node[1] - goal_cell[1])
# the tightest estimate the allowed moves admit (Manhattan when only
# orthogonal steps exist), scaled by heuristic_weight: above 1 the
# search heads for the goal instead of flooding open board, for a
# route at most that factor longer than the shortest
base = dx + dy if self._orthogonal else math.hypot(dx, dy)
return self.heuristic_weight * base
# --- commit / rip -------------------------------------------------------
def _commit(self, conn: _Connection, path: list[Node]) -> None:
conn.path = list(path)
wire_segs, via_cells = _split_path(path)
via_cells = list(via_cells)
if isinstance(conn.a_end, ConductionArea):
via_cells.append((path[0][0], path[0][1]))
if isinstance(conn.b_end, ConductionArea):
via_cells.append((path[-1][0], path[-1][1]))
conn.trace_cells = [(cell, layer) for layer, cells in wire_segs for cell in cells]
conn.via_cells = list(via_cells)
for cell, layer in conn.trace_cells:
self._cell_owner[(*cell, layer)] = conn.index
conn.halo_nodes = []
for (cx, cy), layer in conn.trace_cells:
for dx, dy in self._halo_offsets:
x, y = cx + dx, cy + dy
if 0 <= x < self.cols and 0 <= y < self.rows:
node = (x, y, layer)
self._halo.setdefault(node, []).append(conn.index)
conn.halo_nodes.append(node)
conn.via_halo = []
for cell in conn.via_cells:
for c in self._via_cells(cell):
if c not in self._via_owner:
self._via_owner[c] = conn.index
conn.via_halo.append(c)
ends = ((conn.a_end, wire_segs[0], 0), (conn.b_end, wire_segs[-1], -1)) if wire_segs else ()
for pin, (layer, cells), at in ends:
if not isinstance(pin, Pin):
continue # ended on a zone or a plane: no stub
cell = cells[at]
for c in self._stub_cells(pin.location, cell):
node = (*c, layer)
if node not in self._cell_owner:
self._cell_owner[node] = conn.index
conn.trace_cells.append((c, layer))
# A pin inside a wire keepout can only leave by a via. Its stub to the
# cell centre would be track inside the keepout, so the via goes on
# the pin itself (a via in its own pad) and the stub is left out.
in_pad: dict[int, IntPoint] = {}
if len(wire_segs) > 1:
for idx, pin in ((0, conn.a_end), (len(wire_segs) - 1, conn.b_end)):
layer, cells = wire_segs[idx]
node = (*cells[0], layer)
walled = node in self._keepout or node in self._via_only
if isinstance(pin, Pin) and len(cells) == 1 and walled:
in_pad[idx] = pin.location
conn.wires = []
for idx, (layer, cells) in enumerate(wire_segs):
if idx in in_pad:
continue
points = [self._cell_center(c) for c in cells]
if idx == 0 and isinstance(conn.a_end, Pin):
points.insert(0, conn.a_end.location)
if idx == len(wire_segs) - 1 and isinstance(conn.b_end, Pin):
points.append(conn.b_end.location)
points = _simplify(points)
if len(points) >= 2:
conn.wires.append((layer, points))
conn.vias = [self._cell_center(c) for c in conn.via_cells]
for idx, location in in_pad.items():
# via k joins wire segments k and k + 1
conn.vias[0 if idx == 0 else idx - 1] = location
conn.routed = True
self._settle(conn, -1)
def _rip(self, conn: _Connection) -> None:
for cell, layer in conn.trace_cells:
if self._cell_owner.get((*cell, layer)) == conn.index:
del self._cell_owner[(*cell, layer)]
for cell in conn.via_halo:
if self._via_owner.get(cell) == conn.index:
del self._via_owner[cell]
conn.via_halo = []
for node in conn.halo_nodes:
claims = self._halo.get(node)
if claims is not None:
claims.remove(conn.index)
if not claims:
del self._halo[node]
conn.halo_nodes = []
conn.trace_cells = []
conn.via_cells = []
conn.wires = []
conn.vias = []
conn.routed = False
conn.rip_count += 1
self._settle(conn, +1)
def _crossed_owners(self, path: list[Node], net_no: int, conns: list[_Connection]) -> set[int]:
owners: set[int] = set()
for cx, cy, cl in path:
owner = self._cell_owner.get((cx, cy, cl))
if owner is not None and conns[owner].net_no != net_no:
owners.add(owner)
via_owner = self._via_owner.get((cx, cy))
if via_owner is not None and conns[via_owner].net_no != net_no:
owners.add(via_owner)
for i in self._halo.get((cx, cy, cl), ()):
if conns[i].net_no != net_no:
owners.add(i)
return owners
# --- pin access ---------------------------------------------------------
@staticmethod
def _group_pins(conn: _Connection):
return [*conn.a_group[0], *conn.b_group[0]]
def _build_doorways(self, conns: list[_Connection]) -> None:
"""Map every cell that would close a pin's way out to that pin."""
spread = [(0, 0), *self._halo_offsets]
done: set[int] = set()
for conn in conns:
for pin in self._group_pins(conn):
self._pending[id(pin)] = self._pending.get(id(pin), 0) + 1
if id(pin) in done:
continue
done.add(id(pin))
claim = (id(pin), conn.net_no)
exits: set[Node] = set()
for x, y, layer in self._end_nodes(pin, conn.net_no, conns):
exits.add((x, y, layer))
for c in self._via_cells((x, y)):
exits.update((*c, other) for other in self.layers)
cells: set[Node] = set()
for x, y, layer in exits:
for dx, dy in spread:
if 0 <= x + dx < self.cols and 0 <= y + dy < self.rows:
cells.add((x + dx, y + dy, layer))
for node in cells:
self._doorways.setdefault(node, []).append(claim)
def _settle(self, conn: _Connection, delta: int) -> None:
if not self._pending:
return
for pin in self._group_pins(conn):
if id(pin) in self._pending:
self._pending[id(pin)] += delta
def _access(self, node: Node, net_no: int) -> float:
"""Extra cost for ``net_no`` to use a cell another pin still needs."""
for pin_id, owner_net in self._doorways.get(node, ()):
if owner_net != net_no and self._pending.get(pin_id, 0) > 0:
return self.access_cost
return 0.0
# --- passes -------------------------------------------------------------
def route(self) -> RouteResult:
"""Route all ratsnest connections, using rip-up-and-retry across passes."""
conns = self._build_connections()
self._conns = conns
if not conns:
return RouteResult(self.half_width)
if self.access_cost:
self._build_doorways(conns)
passes = self.max_passes if self.rip_up else 1
best_count = -1
best_snapshot: list[tuple[int, list, list]] | None = None
best_unrouted = len(conns)
# conns[i].index == i is what rip-up relies on, so shuffle a view
order = list(conns)
if self.seed is not None:
random.Random(self.seed).shuffle(order)
if self.route_first:
# stable: the promoted keep their order among themselves, as do the rest
order.sort(key=lambda c: (c.net_no, *_ends_of(c)) not in self.route_first)
for _ in range(passes):
changed = False
for conn in order:
if conn.routed:
continue
if self._try_route(conn, conns):
changed = True
routed_count = sum(1 for c in conns if c.routed)
if routed_count > best_count:
best_count = routed_count
best_unrouted = len(conns) - routed_count
best_snapshot = self._snapshot(conns)
if routed_count == len(conns):
break
if not changed:
break
return self._result_from(best_snapshot or [], best_unrouted)
def _try_route(self, conn: _Connection, conns: list[_Connection]) -> bool:
path = self._search(conn, allow_ripup=False, conns=conns)
if path is None:
if not self.rip_up:
return False
path = self._search(conn, allow_ripup=True, conns=conns)
if path is None:
return False
victims = [conns[i] for i in sorted(self._crossed_owners(path, conn.net_no, conns))]
if self.rollback:
return self._ripup_transaction(conn, path, victims, conns)
for victim in victims:
self._rip(victim)
self._commit(conn, path)
return True
def _ripup_transaction(self, conn, path, victims, conns) -> bool:
"""Route ``conn`` through ``victims``, reroute them at once in free
space, and undo it all if fewer connections end up routed."""
saved = [(v, v.path, v.a_end, v.b_end, v.rip_count) for v in victims]
own_rips = conn.rip_count
for victim in victims:
self._rip(victim)
self._commit(conn, path)
rerouted = 0
for victim in victims:
again = self._search(victim, allow_ripup=False, conns=conns)
if again is not None:
self._commit(victim, again)
rerouted += 1
if 1 + rerouted >= len(victims):
return True # a gain, or an even trade that may pay off later
for victim in victims:
if victim.routed:
self._rip(victim)
self._rip(conn)
conn.rip_count = own_rips
for victim, old_path, a_end, b_end, rips in saved:
victim.a_end, victim.b_end = a_end, b_end
self._commit(victim, old_path)
victim.rip_count = rips
return False
def _build_connections(self) -> list[_Connection]:
pins_by_net = self._pins_by_net()
zones_by_net: dict[int, list] = {}
self._every_zone_by_net: dict[int, list] = {}
for zone in self.board.get_conduction_areas():
if zone.layer in self.layers and zone.net_nos:
self._every_zone_by_net.setdefault(zone.net_nos[0], []).append(zone)
for zone in self.board.get_conduction_areas():
if zone.layer in self.layers and zone.net_nos and self._zone_is_solid(zone):
zones_by_net.setdefault(zone.net_nos[0], []).append(zone)
# planes: zones of a net on an inner power layer, solid by construction
planes_by_net: dict[int, list] = {}
for zone in self.board.get_conduction_areas():
if zone.net_nos and zone.layer in self._power_layers:
planes_by_net.setdefault(zone.net_nos[0], []).append(zone)
plane_ids = frozenset(id(z) for zs in planes_by_net.values() for z in zs)
conns: list[_Connection] = []
nets = set(pins_by_net) | set(zones_by_net) | set(planes_by_net)
# deterministic: fewer-pin nets first, then by net number
for net_no in sorted(nets, key=lambda n: (len(pins_by_net.get(n, [])), n)):
zones = zones_by_net.get(net_no, []) + planes_by_net.get(net_no, [])
groups = _connected_groups(pins_by_net.get(net_no, []), zones, plane_ids)
hubs = [g for g in groups if any(id(z) in plane_ids for z in g[1])]
if hubs:
# a plane net: every other group goes straight to the plane
# (usually a stub and a via), not pad to pad across the board
pairs = [(g, hubs[0]) for g in groups if g is not hubs[0]]
else:
pairs = list(zip(groups, groups[1:], strict=False))
for ga, gb in pairs:
conn = _Connection(len(conns), net_no, _first(ga[0]), _first(gb[0]))
conn.a_group, conn.b_group = ga, gb
conns.append(conn)
return conns
def _pins_by_net(self) -> dict[int, list[Pin]]:
by_net: dict[int, list[Pin]] = {}
for pin in self.board.get_pins():
if not any(layer in self.layers for layer in pin.layers):
continue
for net_no in pin.net_nos:
by_net.setdefault(net_no, []).append(pin)
return by_net
def _snapshot(self, conns: list[_Connection]) -> list[tuple]:
return [
(c.net_no, [(layer, list(pts)) for layer, pts in c.wires], list(c.vias),
(*_ends_of(c), self._left_to_zone(c)))
for c in conns
if c.routed
]
def _result_from(self, snapshot, unrouted: int) -> RouteResult:
result = RouteResult(self.half_width)
result.unrouted = unrouted
for net_no, wires, vias, ends in snapshot:
for layer, points in wires:
result.add_wire(net_no, layer, points)
for location in vias:
result.add_via(net_no, location)
result.connections.append((net_no, wires, vias))
result.connection_ends.append(ends)
routed = {ends[:2] + (net_no,) for net_no, _w, _v, ends in snapshot}
result.failed = [
(c.net_no, *_ends_of(c), self._left_to_zone(c))
for c in self._conns
if _ends_of(c) + (c.net_no,) not in routed
]
return result
def _first(items):
return items[0] if items else None
def _group_label(group) -> str:
pins, zones = group
parts = [f"{p.component_ref}-{p.name}" for p in pins[:3]]
if len(pins) > 3:
parts.append(f"+{len(pins) - 3} pins")
parts += [f"zone {z.name}" for z in zones[:1]]
return "/".join(parts) or "?"
def _ends_of(conn) -> tuple[str, str]:
"""A readable description of what a connection joins."""
return _group_label(conn.a_group), _group_label(conn.b_group)
def _pin_touches_zone(pin: Pin, zone, plane: bool = False) -> bool:
"""A pad on the zone's layer whose centre or a corner lies in the zone.
For a plane on an inner power layer: a through-hole pad (on more than one
copper layer) inside it passes through the plane and is joined to it; an
SMD pad is not, and needs a via.
"""
if plane:
return len(pin.layers) > 1 and zone.polygon is not None and zone.polygon.contains(pin.location)
if zone.layer not in pin.layers or zone.polygon is None:
return False
if zone.polygon.contains(pin.location):
return True
box = pin.shape.bounding_box() if pin.shape is not None else None
if box is None:
return False
corners = (box.ll, IntPoint(box.ur.x, box.ll.y), box.ur, IntPoint(box.ll.x, box.ur.y))
return any(zone.polygon.contains(c) for c in corners)
def _connected_groups(
pins: list[Pin], zones: list, planes: frozenset = frozenset()
) -> list[tuple[list[Pin], list]]:
"""Pins and zones of one net that copper already joins: a pad in a zone
is connected to it, and two zones sharing a pad are one. Only the groups
need routing between them. Pin groups come first, in pin order."""
parent = list(range(len(pins) + len(zones)))
def find(i: int) -> int:
while parent[i] != i:
parent[i] = parent[parent[i]]
i = parent[i]
return i
for j, zone in enumerate(zones):
for i, pin in enumerate(pins):
if _pin_touches_zone(pin, zone, id(zone) in planes):
parent[find(i)] = find(len(pins) + j)
groups: dict[int, tuple[list[Pin], list]] = {}
order: list[int] = []
for i, pin in enumerate(pins):
root = find(i)
if root not in groups:
groups[root] = ([], [])
order.append(root)
groups[root][0].append(pin)
for j, zone in enumerate(zones):
root = find(len(pins) + j)
if root not in groups:
groups[root] = ([], [])
order.append(root)
groups[root][1].append(zone)
return [groups[r] for r in order]
def _split_path(path: list[Node]) -> tuple[list[tuple[int, list[Cell]]], list[Cell]]:
"""Split a node path into per-layer wire segments and via cells."""
wires: list[tuple[int, list[Cell]]] = []
vias: list[Cell] = []
i = 0
n = len(path)
while i < n:
layer = path[i][2]
cells: list[Cell] = []
while i < n and path[i][2] == layer:
cells.append((path[i][0], path[i][1]))
i += 1
wires.append((layer, cells))
if i < n: # a via connects this segment's last cell to the next layer
vias.append(cells[-1])
return wires, vias
def _reconstruct(came_from: dict[Node, Node], current: Node) -> list[Node]:
path = [current]
while current in came_from:
current = came_from[current]
path.append(current)
path.reverse()
return path
def _simplify(points: list[IntPoint]) -> list[IntPoint]:
"""Drop duplicate and collinear points from a polyline."""
out: list[IntPoint] = []
for p in points:
if out and out[-1].x == p.x and out[-1].y == p.y:
continue
if len(out) >= 2:
a, b = out[-2], out[-1]
if (b.x - a.x) * (p.y - a.y) - (b.y - a.y) * (p.x - a.x) == 0:
out[-1] = p
continue
out.append(p)
return out
def route_board(
board: BasicBoard,
*,
trace_width: int,
clearance: int,
layers: list[int] | None = None,
via_cost: float = 10.0,
rip_up: bool = True,
max_passes: int = 10,
orthogonal: bool = False,
via_half: int | None = None,
edge_clearance: int | None = None,
resolution: int = 1,
heuristic_weight: float = 1.0,
seed: int | None = None,
route_first: frozenset | None = None,
access_cost: float = 0.0,
rollback: bool = True,
) -> RouteResult:
"""Convenience wrapper: build a :class:`GridRouter` and route the board."""
router = GridRouter(
board,
trace_width=trace_width,
clearance=clearance,
layers=layers,
via_cost=via_cost,
rip_up=rip_up,
max_passes=max_passes,
orthogonal=orthogonal,
via_half=via_half,
edge_clearance=edge_clearance,
resolution=resolution,
heuristic_weight=heuristic_weight,
seed=seed,
route_first=route_first,
access_cost=access_cost,
rollback=rollback,
)
return router.route()