Glossary

Access set — the components a system reads and writes, plus the channels it produces and consumes. Used by the scheduler to order and parallelise systems.

Activation order — the fixed, seeded order in which systems within a stage run, so any order-sensitive step is reproducible.

Archetype — the set of entities sharing exactly the same components. Storage is organised per archetype.

Attribute — the columnar array storing one component for one archetype, split into chunks.

Boundary — a model-owned resource (the environment, message buffers) written during a stage and finalised at the stage edge.

Channel — a named ordering edge. A system produces or consumes a channel; the scheduler runs producers before consumers.

Chunk — a fixed-size block of rows within an attribute; the unit of parallel iteration.

Component — a plain data type holding one facet of an entity's state.

DetRng — the deterministic RNG, keyed on the run context and a salt so draws do not depend on thread scheduling.

Entity — a compact handle (index and version) identifying an agent.

Environment — model-wide values keyed by name and type.

Feature — a Cargo feature gating an optional layer (model, messaging, gpu, and so on).

Migration — moving an entity between archetypes when its component set changes.

Model — a built simulation: world, environment, agents, and schedulers, advanced with tick.

Nested model — an isolated child Model with its own world and seed, joined to a parent through a bridge.

Reduction — a fold over a query's component column into an accumulator, with per-chunk partials combined stably.

Run context — the per-system (simulation_seed, tick, system_id) passed to each system; the basis for deterministic draws.

Shard — one partition of entity storage, typically one per worker.

Specialisation — how a message type is indexed and delivered (brute-force, bucket, spatial, targeted).

Stage — a group of non-conflicting systems that run in parallel; stages run in sequence.

Sub-scheduler — a named scope of systems sharing the model's world, run before the root scheduler each tick.

System — a unit of per-tick work with a declared access set.