Struct SpawnSchedule 

pub struct SpawnSchedule { /* private fields */ }

Fluent builder for TimedSpawn sequences that feed Scenario::spawns.

Unifies two common authoring shapes in one place:

• Deterministic bursts (fixed origin/destination, fixed tick or regular cadence), where exact tick counts matter — e.g. “20 riders leave the lobby at tick 0”, “1 rider every 600 ticks for 10 minutes”.
• Poisson draws from a TrafficPattern, where the origin/destination pair is stochastic but the arrival process is exponential.

The final Vec<TimedSpawn> is extracted via into_spawns and handed to Scenario::spawns. Scenarios with mixed shapes chain builders via merge:

use elevator_core::scenario::SpawnSchedule;
use elevator_core::stop::StopId;

let schedule = SpawnSchedule::new()
    .burst(StopId(0), StopId(5), 10, 0, 70.0)
    .staggered(StopId(0), StopId(3), 5, 1_000, 300, 70.0);
assert_eq!(schedule.len(), 15);

Implementations

impl SpawnSchedule

pub const fn new() -> Self

Create an empty schedule.

pub fn burst( self, origin: StopId, destination: StopId, count: usize, at_tick: u64, weight: f64, ) -> Self

Append count identical spawns, all firing on at_tick. Use this for the classic “crowd appears simultaneously” shape (morning stand-up, event dismissal).

pub fn staggered( self, origin: StopId, destination: StopId, count: usize, start_tick: u64, stagger_ticks: u64, weight: f64, ) -> Self

Append count spawns starting at start_tick, each stagger_ticks apart. A stagger_ticks = 0 degenerates to burst. Use this for deterministic arrival cadences — e.g. “one rider every 10 seconds” — where Poisson variance would obscure the test signal.

pub fn from_pattern( self, pattern: TrafficPattern, stops: &[StopId], duration_ticks: u64, mean_interval_ticks: u32, weight_range: (f64, f64), rng: &mut impl RngExt, ) -> Self

Append Poisson-distributed spawns from a TrafficPattern over duration_ticks, with exponential inter-arrival times of mean mean_interval_ticks. weight_range is a uniform draw per spawn. The supplied rng advances but is not taken — callers can continue using it for other deterministic draws.

stops must be sorted by position (lobby first) to match TrafficPattern’s lobby-origin peak-pattern assumption. See TrafficPattern::sample_stop_ids.

Returns the schedule with generated spawns appended. If stops has fewer than 2 entries, no spawns are generated (pattern sampling requires at least two stops).

Requires the traffic feature — gated so no-default-features builds (notably the wasm32 gate CI job) don’t pull in rand and the traffic module transitively.

pub fn push(self, spawn: TimedSpawn) -> Self

Append a single spawn. Useful for one-off riders mixed into a larger pattern (e.g. a “stranded top-floor” rider sitting atop a from_pattern stream).

pub fn merge(self, other: Self) -> Self

Absorb another schedule’s spawns. Chainable drop-in for composing heterogeneous arrival shapes — e.g. up-peak burst plus a uniform inter-floor background:

use elevator_core::scenario::SpawnSchedule;
use elevator_core::stop::StopId;
use elevator_core::traffic::TrafficPattern;
use rand::SeedableRng;
let mut rng = rand::rngs::StdRng::seed_from_u64(7);
let stops = vec![StopId(0), StopId(1), StopId(2)];
let background = SpawnSchedule::new().from_pattern(
    TrafficPattern::Uniform, &stops, 10_000, 300, (70.0, 80.0), &mut rng,
);
let up_peak = SpawnSchedule::new().burst(StopId(0), StopId(2), 20, 0, 70.0);
let combined = up_peak.merge(background);
assert!(combined.len() >= 20);

pub const fn len(&self) -> usize

Number of spawns currently in the schedule.

pub const fn is_empty(&self) -> bool

Whether the schedule has no spawns.

pub fn spawns(&self) -> &[TimedSpawn]

Borrow the underlying spawns (useful for inspection in tests).

pub fn into_spawns(self) -> Vec<TimedSpawn>

Consume the builder and return the spawns, ready to drop into Scenario::spawns. ScenarioRunner::new sorts them by tick on construction, so builders don’t need to maintain a sorted invariant.

Trait Implementations

impl Clone for SpawnSchedule

fn clone(&self) -> SpawnSchedule

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SpawnSchedule

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for SpawnSchedule

fn default() -> SpawnSchedule

Returns the “default value” for a type.