From bc75bdd2f28ec25715646009125204487695e223 Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Sun, 30 Nov 2025 16:04:07 +0100
Subject: [PATCH] feat: add ArithmeticCrossover for reals

---
 codes/eoa_lib/src/crossover.rs | 64 ++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)

diff --git a/codes/eoa_lib/src/crossover.rs b/codes/eoa_lib/src/crossover.rs
index 947de702128670e4edf58f645c5875aeebac198f..b195352f922063b8bd1453afcdbea0628a08036a 100644
--- a/codes/eoa_lib/src/crossover.rs
+++ b/codes/eoa_lib/src/crossover.rs
@@ -329,3 +329,67 @@ where
         Population::from_vec(offsprings)
     }
 }
+
+pub struct ArithmeticCrossover<D: Dim, TOutput> {
+    _phantom1: PhantomData<D>,
+    _phantom2: PhantomData<TOutput>,
+}
+
+impl<D, TOutput> ArithmeticCrossover<D, TOutput> {
+    pub fn new() -> Self {
+        Self {
+            _phantom1: PhantomData,
+            _phantom2: PhantomData,
+        }
+    }
+}
+
+impl<D, TOutput> Crossover<2> for ArithmeticCrossover<D, TOutput>
+where
+    D: Dim,
+    DefaultAllocator: Allocator<D>
+{
+    type Chromosome = OVector<f64, D>;
+    type Out = TOutput;
+
+    fn crossover(
+        &self,
+        population: &EvaluatedPopulation<Self::Chromosome, Self::Out>,
+        pairs: impl Iterator<Item = ParentPairing<2>>,
+        rng: &mut dyn RngCore
+    ) -> Population<Self::Chromosome> {
+        let mut offsprings = Vec::new();
+
+        for pair in pairs {
+            let (
+                parent1,
+                parent2
+            ) = (&population.population[pair.x], &population.population[pair.y]);
+
+            let (
+                chromosome1,
+                chromosome2
+            ) = (&parent1.chromosome, &parent2.chromosome);
+
+            offsprings.push(
+                chromosome1.zip_map(
+                    &chromosome2,
+                    |first, second| {
+                        let alpha = rng.random_range(0.0..=1.0);
+                        alpha * first + (1.0 - alpha) * second
+                    }
+                ));
+
+            offsprings.push(
+                chromosome1.zip_map(
+                    &chromosome2,
+                    |first, second| {
+                        let alpha = rng.random_range(0.0..=1.0);
+                        alpha * second + (1.0 - alpha) * first
+                    }
+                ));
+        }
+
+        Population::from_vec(offsprings)
+    }
+}