Struct Patient 

pub struct Patient { /* private fields */ }

A decorator that delays an inner scheduler’s prune until a trial has stopped improving.

It forwards every call to the wrapped Scheduler, with one change: an inner Decision::Prune is suppressed (turned into Decision::Continue) until the trial has gone patience consecutive reports without improving its own best objective value. Pause, Fork and Continue pass through untouched, as does everything from on_trial_end and state (Patient adds no persistent state of its own).

This dampens the failure mode the design warns about — a noisy RL curve that dips for one report and is pruned by an over-eager inner rule even though it was about to recover (prune and schedule). Compose it over any pruner: Patient::new(3, Arc::new(AshaPruner::new(1, 27, 3)?)).

Why it tracks per-trial state

“Improving its own best” needs the trial’s own report history, which the ask-time StudyView does not contain (the reporting trial is not in it) and which no storage handle is offered for. Patient therefore keeps a tiny {best, stale} record per live trial behind a mutex, cleared on on_trial_end — transient bookkeeping, not study state.

Determinism

The improvement count is a deterministic function of the trial’s own reports (which arrive in order on one worker); the inner decision carries whatever determinism the inner scheduler has. Replayable, not pre-determined, under parallelism.

Implementations

impl Patient

pub fn new(patience: u32, inner: Arc<dyn Scheduler>) -> Self

Wraps inner, honoring its prunes only after patience non-improving reports.

pub fn with_objective(self, obj: usize) -> Self

Selects which objective dimension defines “improvement” (default 0).

Trait Implementations

impl Debug for Patient

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

Formats the value using the given formatter.

impl Scheduler for Patient

fn on_trial_end( &self, study: &StudyView, trial: &FrozenTrial, ) -> Result<Vec<Command>>

Forwards to the inner scheduler and clears the finished trial’s tracker.

fn state(&self) -> Result<Option<SchedulerState>>

The inner scheduler’s state — Patient adds none of its own.

fn resume_candidates(&self, study: &StudyView) -> Result<Vec<Command>>

Forwards slot-driven wakeups without changing the inner scheduler’s command semantics.

fn restore_state(&self, blob: &SchedulerState) -> Result<()>

Restores the wrapped scheduler’s state; Patient has no state of its own.

fn scripted_capability(&self) -> ScriptedSchedulerCapability

Declares whether scripted ask/tell can recreate this scheduler.

fn fan_report_mode(&self) -> FanReportMode

Declares whether this scheduler accepts aligned aggregate fan reports.

fn on_report( &self, study: &StudyView, trial: &TrialMeta, step: u64, values: &[f64], ) -> Result<Decision>

Called on every intermediate report.