From abae71139437208822f07bb957d3832f4b5a41e3 Mon Sep 17 00:00:00 2001
From: Rutherther <rutherther@ditigal.xyz>
Date: Mon, 6 Oct 2025 20:31:15 +0200
Subject: [PATCH] feat: add PatternPerturbation

Move by +/- d in random single coordinate.
---
 env/src/perturbation/mod.rs | 36 ++++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/env/src/perturbation/mod.rs b/env/src/perturbation/mod.rs
index 12cbfe4ebd83ce687efbfa95dd404a492970136a..42b3b89a4411d27fb79b8fad9dd071df9d216152 100644
--- a/env/src/perturbation/mod.rs
+++ b/env/src/perturbation/mod.rs
@@ -63,6 +63,42 @@ impl<TRng: Rng, TDistribution: Distribution<f64>, const LEN: usize> Perturbation
     }
 }
 
+pub struct PatternPerturbation<const LEN: usize, TRng: Rng> {
+    d: f64,
+    rng: TRng
+}
+
+impl<const LEN: usize> PatternPerturbation<LEN, rand::rngs::ThreadRng> {
+    pub fn new(d: f64) -> Self {
+        Self {
+            d,
+            rng: rand::rng()
+        }
+    }
+}
+
+impl<const LEN: usize, TRng: Rng> PerturbationOperator for PatternPerturbation<LEN, TRng> {
+    type Chromosome = SVector::<f64, LEN>;
+
+    fn perturb(self: &mut Self, chromosome: &Self::Chromosome) -> Self::Chromosome {
+        let mut chromosome = chromosome.clone();
+
+        // 1. Choose dimension
+        let idx = self.rng.random_range(0..LEN);
+        // 2. Direction
+        let d = if self.rng.random_bool(0.5) {
+            self.d
+        } else {
+            -self.d
+        };
+
+        // Apply
+        chromosome[idx] += d;
+
+        chromosome
+    }
+}
+
 pub enum BoundedPerturbationStrategy {
     /// Trims the value to get a value within bounds
     Trim,