diff --git a/src/algorithms/hill_climber.rs b/src/algorithms/hill_climber.rs
new file mode 100644
index 0000000..f25abdc
--- /dev/null
+++ b/src/algorithms/hill_climber.rs
@@ -0,0 +1,151 @@
+//! `HillClimber` — single-objective greedy local search.
+
+use crate::core::candidate::Candidate;
+use crate::core::objective::Direction;
+use crate::core::population::Population;
+use crate::core::problem::Problem;
+use crate::core::result::OptimizationResult;
+use crate::core::rng::rng_from_seed;
+use crate::traits::{Initializer, Optimizer, Variation};
+
+/// Configuration for [`HillClimber`].
+#[derive(Debug, Clone)]
+pub struct HillClimberConfig {
+ /// Number of mutation iterations.
+ pub iterations: usize,
+ /// Seed for the deterministic RNG.
+ pub seed: u64,
+}
+
+impl Default for HillClimberConfig {
+ fn default() -> Self {
+ Self { iterations: 1000, seed: 42 }
+ }
+}
+
+/// Single-objective greedy hill climber.
+///
+/// Starts from one initializer-sampled decision, repeatedly mutates it via
+/// the variation operator, and keeps the child only when it is strictly
+/// better than the current incumbent. Standard feasibility tiebreaks apply:
+/// feasible beats infeasible, smaller violation wins among infeasibles.
+///
+/// Single-objective only.
+#[derive(Debug, Clone)]
+pub struct HillClimber {
+ /// Algorithm configuration.
+ pub config: HillClimberConfig,
+ /// Initial-decision sampler.
+ pub initializer: I,
+ /// Mutation operator.
+ pub variation: V,
+}
+
+impl HillClimber {
+ /// Construct a `HillClimber`.
+ pub fn new(config: HillClimberConfig, initializer: I, variation: V) -> Self {
+ Self { config, initializer, variation }
+ }
+}
+
+impl
Optimizer
for HillClimber
+where
+ P: Problem + Sync,
+ P::Decision: Send,
+ I: Initializer,
+ V: Variation,
+{
+ fn run(&mut self, problem: &P) -> OptimizationResult {
+ let objectives = problem.objectives();
+ assert!(
+ objectives.is_single_objective(),
+ "HillClimber requires exactly one objective",
+ );
+ let direction = objectives.objectives[0].direction;
+ let mut rng = rng_from_seed(self.config.seed);
+
+ let mut initial = self.initializer.initialize(1, &mut rng);
+ assert!(!initial.is_empty(), "HillClimber initializer returned no decisions");
+ let mut current_decision = initial.remove(0);
+ let mut current_eval = problem.evaluate(¤t_decision);
+ let mut evaluations = 1usize;
+
+ for _ in 0..self.config.iterations {
+ let parents = vec![current_decision.clone()];
+ let children = self.variation.vary(&parents, &mut rng);
+ assert!(!children.is_empty(), "HillClimber variation returned no children");
+ let child_decision = children.into_iter().next().unwrap();
+ let child_eval = problem.evaluate(&child_decision);
+ evaluations += 1;
+
+ let child_better = match (child_eval.is_feasible(), current_eval.is_feasible()) {
+ (true, false) => true,
+ (false, true) => false,
+ (false, false) => {
+ child_eval.constraint_violation < current_eval.constraint_violation
+ }
+ (true, true) => match direction {
+ Direction::Minimize => child_eval.objectives[0] < current_eval.objectives[0],
+ Direction::Maximize => child_eval.objectives[0] > current_eval.objectives[0],
+ },
+ };
+ if child_better {
+ current_decision = child_decision;
+ current_eval = child_eval;
+ }
+ }
+
+ let best = Candidate::new(current_decision, current_eval);
+ let population = Population::new(vec![best.clone()]);
+ let front = vec![best.clone()];
+ OptimizationResult::new(
+ population,
+ front,
+ Some(best),
+ evaluations,
+ self.config.iterations,
+ )
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+ use crate::operators::{GaussianMutation, RealBounds};
+ use crate::tests_support::{SchafferN1, Sphere1D};
+
+ fn make_optimizer(seed: u64) -> HillClimber {
+ HillClimber::new(
+ HillClimberConfig { iterations: 500, seed },
+ RealBounds::new(vec![(-5.0, 5.0)]),
+ GaussianMutation { sigma: 0.3 },
+ )
+ }
+
+ #[test]
+ fn finds_minimum_of_sphere() {
+ let mut opt = make_optimizer(1);
+ let r = opt.run(&Sphere1D);
+ let best = r.best.unwrap();
+ assert!(best.evaluation.objectives[0] < 1e-2, "got f = {}", best.evaluation.objectives[0]);
+ }
+
+ #[test]
+ fn deterministic_with_same_seed() {
+ let mut a = make_optimizer(99);
+ let mut b = make_optimizer(99);
+ let ra = a.run(&Sphere1D);
+ let rb = b.run(&Sphere1D);
+ assert_eq!(
+ ra.best.unwrap().evaluation.objectives,
+ rb.best.unwrap().evaluation.objectives,
+ );
+ }
+
+ #[test]
+ #[should_panic(expected = "exactly one objective")]
+ fn multi_objective_panics() {
+ let mut opt = make_optimizer(0);
+ let _ = opt.run(&SchafferN1);
+ }
+}
diff --git a/src/algorithms/mod.rs b/src/algorithms/mod.rs
index 71fc557..f62687b 100644
--- a/src/algorithms/mod.rs
+++ b/src/algorithms/mod.rs
@@ -1,6 +1,7 @@
//! Built-in reference optimizers.
pub mod differential_evolution;
+pub mod hill_climber;
pub mod moead;
pub mod nsga2;
pub mod nsga3;
@@ -10,6 +11,7 @@ pub mod random_search;
pub mod spea2;
pub use differential_evolution::*;
+pub use hill_climber::*;
pub use moead::*;
pub use nsga2::*;
pub use nsga3::*;
diff --git a/src/prelude.rs b/src/prelude.rs
index 64cb471..b638028 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -22,7 +22,7 @@ pub use crate::operators::{
};
pub use crate::algorithms::{
- DifferentialEvolution, DifferentialEvolutionConfig, Moead, MoeadConfig, Nsga2,
- Nsga2Config, Nsga3, Nsga3Config, Paes, PaesConfig, RandomSearch, RandomSearchConfig,
- Spea2, Spea2Config,
+ DifferentialEvolution, DifferentialEvolutionConfig, HillClimber, HillClimberConfig,
+ Moead, MoeadConfig, Nsga2, Nsga2Config, Nsga3, Nsga3Config, Paes, PaesConfig,
+ RandomSearch, RandomSearchConfig, Spea2, Spea2Config,
};