Porting from IPKISS 2025.12 to IPKISS 2026.03

Porting place_and_route instance definitions

In IPKISS 2026.03, the insts argument of i3.place_and_route is deprecated. Instances should now be declared in the specs list using i3.Inst.

You can pass a layout object with existing instances (for example the layout argument of generate(self, layout) or the result of a previous place_and_route call). The function copies the input layout and returns a new layout object with the extra instances and routing added according to the specs.

Update your code as follows:

• Move instance definitions into the specs list using i3.Inst.

• For chained calls, pass the previous result via layout=….

Old (deprecated):

layout = i3.place_and_route(
    insts={
        "splitter": WgYSplitter(),
        "combiner": WgYCombiner(),
        "gc1": GratingCoupler(),
        "gc2": GratingCoupler(),
    },
    specs=[
        i3.Place("splitter", (0, 0)),
        i3.Place("combiner", (30, 20), relative_to="splitter"),
        i3.Place("gc1:out", (-100, 0), relative_to="splitter@CW"),
        i3.Place("gc2:out", (100, 0), angle=180, relative_to="combiner@CE"),
    ],
)

New (expected format):

layout = i3.place_and_route(
    layout=layout,
    specs=[
        i3.Inst("splitter", WgYSplitter()),
        i3.Inst("combiner", WgYCombiner()),
        i3.Inst(["gc1", "gc2"], GratingCoupler()),

        i3.Place("splitter", (0, 0)),
        i3.Place("combiner", (30, 20), relative_to="splitter"),
        i3.Place("gc1:out", (-100, 0), relative_to="splitter@CW"),
        i3.Place("gc2:out", (100, 0), angle=180, relative_to="combiner@CE"),
    ],
)

Porting i3.Circuit instance definitions

The insts property of i3.Circuit is deprecated. Do not pass insts=… when constructing a circuit and do not implement _default_insts. Instead, define instances with i3.Inst in the specs list.

Update your code as follows:

• Remove insts and _default_insts.

• Add instance definitions to _default_specs (or specs=…) using i3.Inst.

Old (deprecated):

class MyCircuit(i3.Circuit):
    def _default_insts(self):
        return {
            "splitter": WgYSplitter(),
            "combiner": WgYCombiner(),
        }

    def _default_specs(self):
        return [
            i3.Place("splitter", (0, 0)),
            i3.Place("combiner", (30, 20), relative_to="splitter"),
        ]

New (expected format):

class MyCircuit(i3.Circuit):
    def _default_specs(self):
        return [
            i3.Inst("splitter", WgYSplitter()),
            i3.Inst("combiner", WgYCombiner()),
            i3.Place("splitter", (0, 0)),
            i3.Place("combiner", (30, 20), relative_to="splitter"),
        ]