| name | using-simulation-foundations |
| description | Use when a simulation needs numerical-model, integration, stability, control, stochastic or determinism checks. |
Simulation Foundations
Use this contract for the concrete task. Apply a short relevant check for a small change; expand investigation when the failure, risk or requested artifact warrants it. Resolve facts from the repository and runtime before imposing a process. Delegation is optional and should answer a bounded unresolved question.
Mathematical and numerical contract
Identify state, units, transitions/rates, time scale, boundaries and the behavior the simulation must preserve. Choose continuous, discrete-event or hybrid modeling from the quantities and workload; an ODE is not mandatory for every game system.
- State conservation, positivity, boundedness, equilibrium and event-order invariants relevant to the model.
- Select an integrator using stiffness, step size, error/energy behavior and runtime budget. A locally accurate method may drift or destabilize over the required horizon.
- Distinguish continuous-model stability from discrete-update stability. Linearization/eigenvalues have local assumptions and inconclusive cases; they do not prove all nonlinear trajectories safe.
- Test boundaries, large time steps, long horizons and sensitivity to parameters/initial state. Mathematical predictions and empirical traces should agree within the declared tolerance.
- Define determinism scope: same process, platform or cross-machine. Control RNG streams and arithmetic/order as required; fixed timestep or shared seed alone does not prove replay equivalence.
- For controllers, record target, delay, saturation and disturbance assumptions. Validate overshoot, windup and response under actual update timing.
- For random systems, distinguish the intended distribution from player-perceived fairness constraints such as pity bounds. Test both statistical behavior and deterministic replay where required.
Evidence and output
Produce the model and assumptions, selected method/step policy, invariant/error budget and validation traces. State what is analytically established, locally approximated or observed. Do not promise zero desyncs, no extinction or no overshoot from reading a recipe.
Fault-specific references
- Rates/continuous behavior:
differential-equations-for-games.md. - State/reachability:
state-space-modeling.md. - Explosions or equilibrium questions:
stability-analysis.md, withnumerical-methods.mdfor discrete updates. - Tracking/delay/oscillation:
feedback-control-theory.md. - Model mismatch:
continuous-vs-discrete.md. - Sensitivity/desync or random-process behavior: chaos/stochastic sheets below.
Game-engine implementation and fidelity/LOD decisions belong to simulation tactics; system replay architecture belongs to determinism/replay. Load derivations only when needed to establish the task's proof or explain a concept.
Optional references
All sheets below are in this directory. Choose a sheet because its checks or examples help the task; there is no requirement to read the catalog in sequence. Verify time-sensitive APIs and numerical/performance claims before relying on examples.