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Planning Solutions

The top-level container that holds entities, facts, and the current score.

A planning solution is the root struct that represents your entire problem and its current solution state. It owns your entity collections, problem facts, and score field.

The #[planning_solution] Macro

use solverforge::prelude::*;

#[planning_solution(constraints = "crate::constraints::define_constraints")]
pub struct Schedule {
    #[problem_fact_collection]
    pub employees: Vec<Employee>,

    #[problem_fact_collection]
    pub availability: Vec<Availability>,

    #[planning_entity_collection]
    pub shifts: Vec<Shift>,

    #[planning_score]
    pub score: Option<HardSoftScore>,
}

The constraints parameter is optional, but it is what enables the generated Solvable and Analyzable implementations used by the stock runtime.

Field Attributes

#[planning_entity_collection]

Marks a Vec<T> field containing planning entities. The solver iterates these collections to find variables to change.

#[planning_entity_collection]
pub shifts: Vec<Shift>,

#[problem_fact_collection]

Marks a Vec<T> field containing immutable problem facts. Used by constraints but never modified by the solver.

#[problem_fact_collection]
pub employees: Vec<Employee>,

#[planning_score]

Marks the field that holds the current solution quality. Must be Option<ScoreType>.

#[planning_score]
pub score: Option<HardSoftScore>,

Supported score types: SoftScore, HardSoftScore, HardMediumSoftScore, HardSoftDecimalScore, BendableScore.

Generated Helpers

When constraints = "..." is present, #[planning_solution] also generates:

  • A {Name}ConstraintStreams<Sc> trait implemented on ConstraintFactory, so you can write factory.shifts() instead of repeating for_each(...)
  • Solvable for retained-job solving through SolverManager::solve()
  • Analyzable for score breakdowns via analyze()

Generated constraint stream accessors are the default way to start constraints over planning entity and problem fact collections. See Constraint Factory Methods for the full method contract and the lower-level for_each(...) escape hatch.

For advanced list-shadow workflows, the struct can also carry #[shadow_variable_updates(...)]. When present, the macro generates PlanningSolution::update_entity_shadows(...) and update_all_shadows() overrides directly on the solution type, and the stock ScoreDirector calls those hooks automatically during solving and score analysis.

Requirements

  • Must be a named Rust struct
  • Must have exactly one #[planning_score] field
  • Must have at least one #[planning_entity_collection] field for stock solving

Common value-range setup lives on the entity side, for example #[planning_variable(value_range_provider = "employees")].

See Also