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regelum is a framework for modeling Phased Reactive Systems: systems that execute one tick at a time, activate different groups of nodes in different phases, and move between phases with explicit transitions.

The framework is built around four surface ideas:

• nodes declare typed inputs and outputs;
• phases define which node instances are active together;
• transitions decide how one phase hands control to the next;
• continuous nodes can be grouped into ODE systems and integrated inside a phase;
• compilation resolves links, schedules nodes, and catches mistakes early.

Install from PyPI with uv:

uv add regelum

import regelum as rg


class TemperatureSensor(rg.Node):
    class Outputs(rg.NodeOutputs):
        temperature: float = rg.Output(initial=19.0)

    def run(self) -> Outputs:
        return self.Outputs(temperature=21.5)


class HeaterController(rg.Node):
    class Inputs(rg.NodeInputs):
        temperature: float = rg.Input(
            source=TemperatureSensor.Outputs.temperature,
        )

    class Outputs(rg.NodeOutputs):
        heater_on: bool

    def run(self, inputs: Inputs) -> Outputs:
        return self.Outputs(heater_on=inputs.temperature < 22.0)


sensor = TemperatureSensor(name="room_sensor")
controller = HeaterController(name="heater_controller")

system = rg.PhasedReactiveSystem(
    phases=[
        rg.Phase(
            "control",
            nodes=(sensor, controller),
            transitions=(rg.Goto(rg.terminate),),
            is_initial=True,
        ),
    ],
)

Local development

Set up the repository, install hooks, and run the full local gate:

uv sync --all-groups
uv run prek install --hook-type pre-commit --hook-type pre-push
uv run prek run --all-files

The pre-push hook runs pytest, so a normal git push exercises the test suite automatically.

Local docs

uv run --group docs mkdocs serve \
  --watch docs \
  --watch mkdocs.yml \
  --watch src/regelum \
  --watch README.md

Build the static site:

uv run --group docs mkdocs build