54 lines
1.9 KiB
Rust
54 lines
1.9 KiB
Rust
//! Discrete-event simulation engine.
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//!
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//! 离散事件仿真引擎。
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//!
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//! The engine advances a clock by jumping from one event to the next. It
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//! holds the event queue, the current simulation time, and the statistics a
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//! caller needs to judge a run. What an event means is the caller's: it
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//! supplies a handler that receives the event and may schedule more events,
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//! and the engine only sequences the calls.
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//!
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//! The engine keeps the simulation deterministic. Events at the same instant
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//! are delivered in the order they were scheduled, which the event queue
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//! guarantees, so a run with the same inputs produces the same output. That
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//! is what makes a result reproducible and a cross-check against another
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//! implementation meaningful.
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//!
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//! The engine stops for one of four reasons, reported as a
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//! [`StopReason`]:
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//! the queue empties, the simulation reaches its time limit, the caller asks
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//! it to stop, or an event limit is reached. The last two exist so that a
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//! model that schedules events forever cannot run without bound.
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//!
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//! ```
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//! use apsis_sim_engine::Engine;
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//!
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//! let mut engine = Engine::new();
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//! engine.schedule(10.0, "hello");
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//!
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//! let mut seen = Vec::new();
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//! let outcome = engine.run(|engine, event| {
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//! seen.push(event.payload);
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//! // The handler schedules the next event, which the engine delivers
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//! // after this one. It schedules it only once, so the queue drains.
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//! if event.payload == "hello" {
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//! engine.schedule(20.0, "world");
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//! }
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//! });
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//!
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//! assert_eq!(seen, vec!["hello", "world"]);
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//! assert_eq!(outcome.executed, 2);
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//! assert_eq!(engine.now(), 20.0);
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//! ```
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#![forbid(unsafe_code)]
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#![deny(missing_docs)]
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mod engine;
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mod outcome;
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pub use engine::Engine;
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pub use outcome::{EngineOutcome, EngineState, StopReason};
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pub use apsis_event::{Event, EventId, EventQueue, QueueState};
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