Rust

Rust is the only supported simulation core. It owns scheduling, simulation state, random streams and model execution. Host-language packages adapt this core through a native ABI or Rust-compiled WebAssembly.

Start from the pinned source

git clone https://github.com/edithatogo/kairos.git
cd kairos
cargo test --locked -p kairo-ecs-core -p kairo-ecs-types

Use the repository’s rust-toolchain.toml and lockfile. In a crate with path dependencies on kairo-ecs-core and kairo-ecs-types, a minimal example is:

use kairo_ecs_core::Scheduler;
use kairo_ecs_types::{EventKind, ScheduleRequest, SimTime, StepOutcome};

fn main() {
    let mut scheduler = Scheduler::new();
    let id = scheduler.schedule(ScheduleRequest {
        at: SimTime::from_ticks(10),
        priority: 0,
        kind: EventKind::custom(1),
        entity: None,
    });
    assert!(scheduler.cancel(id));
    assert_eq!(scheduler.step(), StepOutcome::Empty);
}

Event ordering uses time, priority and insertion sequence. SimTime is an unsigned 128-bit tick count; models define and record the unit. The complete tutorial explains cancellation, source tests and model-building next steps.

Choose a capability deliberately

Need	Source area	Qualification boundary
Core scheduling and state	kairo-ecs-core, types, state, rng	Model replay also depends on model version, RNG stream version and numerical rules.
DES and ABM primitives	kairo-ecs-des, kairo-ecs-abm	Validate application semantics and composed behaviour separately.
Data exchange	kairo-ecs-arrow	Optional native dependencies, formats and ownership require consumer-specific checks.
Parallel/distributed execution	kairo-ecs-pdes, mpi, grpc	Bounded native evidence exists; choose workloads using measured results.
GPU execution	kairo-ecs-gpu, webgpu	Particular kernels and device paths are qualified, not arbitrary model offload.
Scientific methods	Game-theory, inference and FMI crates	Method names are not independent correctness or interoperability evidence.

See the crate inventory, current-state review and capability register. The alpha APIs may change. Keep domain models in the consuming application and pin its Kairos dependency to a reviewed version.