Migration

kfactory 3.0

With kfactory 3.0, several modules, functions, and interfaces have changed.

3.0 Change Summary

Area	What changed	Before (2.x)	After (3.0)
Module	`virtual.utils` moved	`kfactory.factories.virtual.utils`	`kfactory.factories.utils`
Routing	`route_L` / `route_elec` removed	`route_elec(cell, p1, p2)`	`route_bundle(cell, [p1], [p2])`
Routing	`routing.optical.route` removed	`route(cell, p1, p2, ...)`	`route_bundle(cell, [p1], [p2], ...)`
Routing	`place90` deprecated	`place90(cell, p1, p2, pts)`	`place_manhattan(cell, p1, p2, pts)`
Parameters	`start_straights` deprecated	`start_straights=100`	`starts=100`
Parameters	`end_straights` deprecated	`end_straights=100`	`ends=100`
Schematics	Routing via `KCLayout` registry	—	`@kcl.routing_strategy` + `schematic.add_route(...)`

Module Reorganization

kfactory.factories.virtual.utils has been moved to kfactory.factories.utils to unify it with other factory utilities.

# Before (2.x)
from kfactory.factories.virtual.utils import extrude_backbone, extrude_backbone_dynamic

# After (3.0)
from kfactory.factories.utils import extrude_backbone, extrude_backbone_dynamic

Removed Routing Functions

The following routing functions have been removed. Use route_bundle instead.

routing.electrical.route_L — removed
routing.electrical.route_elec — removed
routing.optical.route — removed

# Before (2.x) — electrical
from kfactory.routing.electrical import route_L, route_elec
route_elec(cell, port1, port2, ...)

# After (3.0) — electrical
from kfactory.routing.electrical import route_bundle
route_bundle(cell, start_ports=[port1], end_ports=[port2], separation=..., ...)

# Before (2.x) — optical
from kfactory.routing.optical import route
route(cell, port1, port2, straight_factory=..., bend90_cell=..., ...)

# After (3.0) — optical
from kfactory.routing.optical import route_bundle
route_bundle(
    cell,
    start_ports=[port1],
    end_ports=[port2],
    separation=...,
    straight_factory=...,
    bend90_cell=...,
)

Deprecated Parameters in `route_bundle`

In both routing.optical.route_bundle and routing.electrical.route_bundle:

start_straights is deprecated — use starts instead
end_straights is deprecated — use ends instead

# Before (2.x)
route_bundle(cell, start_ports, end_ports, separation=..., start_straights=100, end_straights=100, ...)

# After (3.0)
route_bundle(cell, start_ports, end_ports, separation=..., starts=100, ends=100, ...)

Deprecated `place90`

routing.optical.place90 is deprecated. Use place_manhattan instead.

# Before (2.x)
from kfactory.routing.optical import place90
place90(cell, p1, p2, pts, ...)

# After (3.0)
from kfactory.routing.optical import place_manhattan
place_manhattan(cell, p1, p2, pts, ...)

Routing Interface for Schematics

In order to enable routing in schematics, routing strategy functions must be registered on the KCLayout instance. Registered strategies can then be referenced by name in Schematic.add_route.

Registering a Routing Strategy

Use the @kcl.routing_strategy decorator or assign directly to kcl.routing_strategies:

import kfactory as kf

kcl = kf.KCLayout("MY_PDK")

@kcl.routing_strategy
def route_bundle(cell, start_ports, end_ports, **kwargs):
    ...

# Or register directly:
kcl.routing_strategies["my_custom_route"] = my_routing_function

Using Routes in a Schematic

The Schematic.add_route method creates a route bundle connecting start and end ports using a named routing strategy:

schematic = kf.Schematic(kcl=kcl)

# Add instances
mmi1 = schematic.add_instance("mmi1", mmi_factory, settings={...})
mmi2 = schematic.add_instance("mmi2", mmi_factory, settings={...})

# Place instances
mmi1.place(...)
mmi2.place(...)

# Route between instances
schematic.add_route(
    name="optical_route",
    start_ports=[mmi1.ports["o2"]],
    end_ports=[mmi2.ports["o1"]],
    routing_strategy="route_bundle",
    separation=10_000,
    # additional **settings are forwarded to the routing strategy function
)

# Build the cell
cell = schematic.create_cell(output_type=kf.KCell)

When create_cell is called, the schematic looks up the routing strategy by name from kcl.routing_strategies (or from the routing_strategies argument to create_cell) and calls it with the resolved ports and settings.