Crate hyperopt_core 

hyperopt-core

Core abstractions for hyperopt-rs, an Optuna-shaped hyperparameter optimization framework for Rust. This crate defines the foundational types and the three extension traits everything else plugs into:

• Sampler — a pluggable search algorithm (random, grid, TPE, …).
• Pruner — a pluggable early-stopping policy.
• Storage — where trial history lives (in-memory, SQLite, …).

Third parties can depend on just hyperopt-core to implement a new sampler or pruner without pulling in SQLite or rayon.

Define-by-run

The search space is not declared up front. Instead the user’s objective closure receives a TrialContext and calls suggest_* methods on it; each call records a Distribution and asks the active Sampler for a Value. This allows conditional/dynamic search spaces — a later suggestion can depend on an earlier one — which is the design this framework is built around.

study.optimize(|trial| {
    let x = trial.suggest_float("x", -10.0, 10.0);
    let y = trial.suggest_float("y", -10.0, 10.0);
    Ok((x - 2.0).powi(2) + (y + 3.0).powi(2)) // minimize
}, 100)?;

Structs

ParamRecord

One recorded (name, distribution, value) triple, in suggestion order.

Study

A single optimization run: a direction, a sampler, a pruner, and a storage backend, tied to a named study whose trials live in that storage.

StudyMetadata

Persisted study-level metadata (everything about a study except its trials).

StudyState

A read-only snapshot of a study’s history, handed to samplers and pruners.

Trial

A single optimization trial: its suggested parameters, intermediate reports, and final objective value.

TrialContext

The handle passed into the user’s objective closure.

Enums

Direction

Optimization direction: whether the objective should be minimized or maximized. Samplers and pruners read this from StudyState::direction and adjust accordingly (e.g. TPE always minimizes internally, negating values under Maximize).

Distribution

The search-space shape recorded for a single suggested parameter.

HyperoptError

Errors raised by crate::Study operations (currently all storage-backed).

ObjectiveError

Signalled by a user objective to describe how a trial ended.

StorageError

Errors a Storage backend can raise.

TrialState

Lifecycle state of a single trial.

Value

A concrete hyperparameter value suggested for a trial.

Traits

Pruner

A pluggable early-stopping policy.

Sampler

A pluggable search algorithm.

Storage

Where a study’s trial history lives.

Suggest

The portable objective interface: exactly the operations a user objective performs on a trial (suggest parameters, report intermediate values, ask whether to prune).

Type Aliases

ObjectiveResult

The value an objective closure returns for one trial.