Introduction

What is SPX?

SPX is a deterministic simulation stack you can run locally and drive from code. You author Models, start live Instances on the SPX Server, and step simulation time explicitly from a client (for example, spx-python) so tests are repeatable.

Mental model

• Model: a definition (usually YAML, optionally backed by custom Python components) describing attributes, actions, timers, communications, and scenarios.

• Instance: a running copy of a Model with state you can inspect/mutate.

• Scenario: a repeatable script of events (fault injection, parameter changes, sequencing).

• MiL test: a Model-in-the-Loop test that drives SPX deterministically as the plant/device while your Software Under Test acts as the real client.

• Snapshot: a captured simulation state you can restore to get a known starting point.

Where to start

• Bring the server up: Installation Guide

• Build a first Model + Instance: Build Your First Simulation

• Make it testable: Use in Unit Tests (MiL)

• Capture/restore state: Snapshots — Getting Started

• Extend beyond YAML: Extending Simulations