Struct ConstructionPhaseFactory

Source

pub struct ConstructionPhaseFactory<S, M, F>where
    S: PlanningSolution,
    M: Move<S> + Clone + Send + Sync + 'static,
    F: Fn() -> Box<dyn EntityPlacer<S, M>> + Send + Sync,
{ /* private fields */ }

Expand description

Factory for creating construction heuristic phases.

Construction heuristic phases build an initial solution by assigning values to uninitialized planning variables. The factory provides fresh phase instances for each solve.

§Type Parameters

S - The planning solution type
M - The move type (typically ChangeMove)
F - The closure type that creates entity placers

§Example

use solverforge_solver::manager::{ConstructionPhaseFactory, SolverPhaseFactory};
use solverforge_solver::heuristic::r#move::ChangeMove;
use solverforge_solver::heuristic::selector::{
    FromSolutionEntitySelector, StaticTypedValueSelector,
};
use solverforge_solver::phase::construction::QueuedEntityPlacer;
use solverforge_core::domain::PlanningSolution;
use solverforge_core::score::SimpleScore;

#[derive(Clone)]
struct Sol { values: Vec<Option<i32>>, score: Option<SimpleScore> }
impl PlanningSolution for Sol {
    type Score = SimpleScore;
    fn score(&self) -> Option<Self::Score> { self.score }
    fn set_score(&mut self, score: Option<Self::Score>) { self.score = score; }
}

fn get_v(s: &Sol, idx: usize) -> Option<i32> { s.values.get(idx).copied().flatten() }
fn set_v(s: &mut Sol, idx: usize, v: Option<i32>) { if let Some(x) = s.values.get_mut(idx) { *x = v; } }

type M = ChangeMove<Sol, i32>;

// Create a first-fit construction phase factory
let factory = ConstructionPhaseFactory::<Sol, M, _>::first_fit(|| {
    let entity_sel = Box::new(FromSolutionEntitySelector::new(0));
    let value_sel = Box::new(StaticTypedValueSelector::new(vec![1, 2, 3]));
    Box::new(QueuedEntityPlacer::new(entity_sel, value_sel, get_v, set_v, 0, "value"))
});

// Create phase when solving
let phase = factory.create_phase();
assert_eq!(phase.phase_type_name(), "ConstructionHeuristic");

§Forager Types

ForagerType::FirstFit: Accepts the first valid assignment (fast)
ForagerType::BestFit: Evaluates all options and picks the best (better quality)

Implementations§

Source §

impl<S, M, F> ConstructionPhaseFactory<S, M, F>
where S: PlanningSolution, M: Move<S> + Clone + Send + Sync + 'static, F: Fn() -> Box<dyn EntityPlacer<S, M>> + Send + Sync,

Source

pub fn new(forager_type: ForagerType, placer_factory: F) -> Self

Creates a new construction phase factory with the specified forager type.

§Arguments

forager_type - The type of forager to use (FirstFit or BestFit)
placer_factory - A closure that creates entity placers

§Example

use solverforge_solver::manager::ConstructionPhaseFactory;
use solverforge_solver::phase::construction::{ForagerType, QueuedEntityPlacer};
use solverforge_solver::heuristic::r#move::ChangeMove;
use solverforge_solver::heuristic::selector::{FromSolutionEntitySelector, StaticTypedValueSelector};
use solverforge_core::domain::PlanningSolution;
use solverforge_core::score::SimpleScore;

type M = ChangeMove<S, i32>;

let factory = ConstructionPhaseFactory::<S, M, _>::new(ForagerType::BestFit, || {
    let es = Box::new(FromSolutionEntitySelector::new(0));
    let vs = Box::new(StaticTypedValueSelector::new(vec![1, 2]));
    Box::new(QueuedEntityPlacer::new(es, vs, get_v, set_v, 0, "v"))
});

Source

pub fn first_fit(placer_factory: F) -> Self

Creates a factory with FirstFit forager.

FirstFit accepts the first valid assignment for each entity, making it fast but potentially producing lower quality initial solutions.

§Example

use solverforge_solver::manager::ConstructionPhaseFactory;
use solverforge_solver::phase::construction::QueuedEntityPlacer;
use solverforge_solver::heuristic::r#move::ChangeMove;
use solverforge_solver::heuristic::selector::{FromSolutionEntitySelector, StaticTypedValueSelector};
use solverforge_core::domain::PlanningSolution;
use solverforge_core::score::SimpleScore;

type M = ChangeMove<S, i32>;

let factory = ConstructionPhaseFactory::<S, M, _>::first_fit(|| {
    let es = Box::new(FromSolutionEntitySelector::new(0));
    let vs = Box::new(StaticTypedValueSelector::new(vec![1, 2, 3]));
    Box::new(QueuedEntityPlacer::new(es, vs, get_v, set_v, 0, "v"))
});

Source

pub fn best_fit(placer_factory: F) -> Self

Creates a factory with BestFit forager.

BestFit evaluates all possible values for each entity and selects the one that produces the best score. Slower but produces better initial solutions.

§Example

use solverforge_solver::manager::ConstructionPhaseFactory;
use solverforge_solver::phase::construction::QueuedEntityPlacer;
use solverforge_solver::heuristic::r#move::ChangeMove;
use solverforge_solver::heuristic::selector::{FromSolutionEntitySelector, StaticTypedValueSelector};
use solverforge_core::domain::PlanningSolution;
use solverforge_core::score::SimpleScore;

type M = ChangeMove<S, i32>;

let factory = ConstructionPhaseFactory::<S, M, _>::best_fit(|| {
    let es = Box::new(FromSolutionEntitySelector::new(0));
    let vs = Box::new(StaticTypedValueSelector::new(vec![1, 2, 3]));
    Box::new(QueuedEntityPlacer::new(es, vs, get_v, set_v, 0, "v"))
});