L10 Stateful Flows and Reset Contracts

Metadata

• Lecture ID: L10
• Track: D (Closed-Loop, State, and Feedback)
• Tier: 2-3
• Duration: 20 minutes
• Prerequisites: L07

Learning Objectives

1. Implement stateful flows with explicit reset behavior.
2. Use pipe.reset() to reinitialize pipeline state deterministically.
3. Validate two-run equivalence after reset.

Core Concept

• Mental model: reset is a contract, not an afterthought.
• Key pitfall: hidden state persisting across debug runs.

Live Demo Mapping

• Primary runnable file: examples/tutorial/d_closed_loop_state_feedback/04_stateful_flow_reset.py

Runnable Commands

Run from repository root:

pixi run python -m examples.tutorial.d_closed_loop_state_feedback.04_stateful_flow_reset --steps 5 --dt 0.1

What To Observe

• Run #1 increments state as expected.
• Reset clears internal counter state.
• Run #2 restarts from the same initial condition.

Failure Drill

• Remove reset() implementation in Counter and show state leakage across runs.

Exercise

• Required: verify first printed value after reset is identical to first run.
• Stretch: add another state variable and include it in reset contract.

Evaluation Rubric

• Pass: learner can explain deterministic reset criteria.
• Failure signature: learner cannot detect state leakage in repeated runs.

Follow-up

• Next lecture: l11_monitoring_and_feedback_loops.md