From a7c70462b23d9c4381d2f729244abc19d73f74c2 Mon Sep 17 00:00:00 2001
From: Fredrik Robertsen <fredrikr79@pm.me>
Date: Sun, 8 Feb 2026 22:45:40 +0100
Subject: [PATCH] readd single-point and some mutation operators

---
 src/common.odin |  6 ++---
 src/ga.odin     | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/src/common.odin b/src/common.odin
index b9e74f8..92f9e2a 100644
--- a/src/common.odin
+++ b/src/common.odin
@@ -13,10 +13,10 @@ TOURNAMENT_SIZE :: 5
 CROSSOVER_RATE :: 0.7
 MUTATION_RATE :: 0.01
 
-SURVIVOR_SELECTION_POLICY :: probabilistic_crowding
-PARENT_SELECTION_POLICY :: roulette_selection
-CROSSOVER_POLICY :: uniform_crossover
+PARENT_SELECTION_POLICY :: random_selection
+CROSSOVER_POLICY :: single_point_crossover
 MUTATION_POLICY :: bit_flip_mutation
+SURVIVOR_SELECTION_POLICY :: generational_replacement
 
 RANDOM_SEED :: u64(42)
 OUTPUT_FILE :: "output/data.csv"
diff --git a/src/ga.odin b/src/ga.odin
index 84d2253..e0966bc 100644
--- a/src/ga.odin
+++ b/src/ga.odin
@@ -206,6 +206,29 @@ roulette_selection :: proc(pop: ^Population, fitnesses: []f64, maximize: bool) -
 	return pop[len(pop) - 1]
 }
 
+single_point_crossover :: proc(parent1, parent2: Chromosome) -> (Chromosome, Chromosome) {
+	if rand.float64() > CROSSOVER_RATE {
+		return clone_chromosome(parent1), clone_chromosome(parent2)
+	}
+
+	size := bit_array.len(parent1)
+	point := rand.int_max(size)
+
+	child1 := bit_array.create(size)
+	child2 := bit_array.create(size)
+
+	for i in 0 ..< point {
+		bit_array.set(child1, i, bit_array.get(parent1, i))
+		bit_array.set(child2, i, bit_array.get(parent2, i))
+	}
+
+	for i in point ..< size {
+		bit_array.set(child1, i, bit_array.get(parent2, i))
+		bit_array.set(child2, i, bit_array.get(parent1, i))
+	}
+
+	return child1, child2
+}
 
 two_point_crossover :: proc(parent1, parent2: Chromosome) -> (Chromosome, Chromosome) {
 	size := bit_array.len(parent1)
@@ -258,6 +281,45 @@ bit_flip_mutation :: proc(chrom: Chromosome) {
 	}
 }
 
+swap_mutation :: proc(chromosome: Chromosome) {
+	size := bit_array.len(chromosome)
+	if rand.float64() < MUTATION_RATE {
+		i := rand.int_max(size)
+		j := rand.int_max(size)
+
+		bit_i := bit_array.get(chromosome, i)
+		bit_j := bit_array.get(chromosome, j)
+
+		bit_array.set(chromosome, i, bit_j)
+		bit_array.set(chromosome, j, bit_i)
+	}
+}
+
+inversion_mutation :: proc(chromosome: Chromosome) {
+	size := bit_array.len(chromosome)
+	if rand.float64() < MUTATION_RATE {
+		point1 := rand.int_max(size)
+		point2 := rand.int_max(size)
+
+		if point1 > point2 {
+			point1, point2 = point2, point1
+		}
+
+		// Reverse segment
+		for i := 0; i < (point2 - point1 + 1) / 2; i += 1 {
+			left := point1 + i
+			right := point2 - i
+
+			bit_left := bit_array.get(chromosome, left)
+			bit_right := bit_array.get(chromosome, right)
+
+			bit_array.set(chromosome, left, bit_right)
+			bit_array.set(chromosome, right, bit_left)
+		}
+	}
+}
+
+
 clone_chromosome :: proc(chrom: Chromosome) -> Chromosome {
     size := bit_array.len(chrom)
     clone := bit_array.create(size)