From fa8d8ab89f42a42171588be1272f7d5cd3c09668 Mon Sep 17 00:00:00 2001 From: stonelv Date: Sat, 2 May 2026 18:24:14 +0800 Subject: [PATCH] island by dogfooding round 3 --- pygad/islandga.py | 32 ++++++++++++------- tests/test_islandga.py | 71 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 91 insertions(+), 12 deletions(-) diff --git a/pygad/islandga.py b/pygad/islandga.py index bd111ea..8c98fb2 100644 --- a/pygad/islandga.py +++ b/pygad/islandga.py @@ -237,7 +237,9 @@ def _replace_individuals(self, ga_instance, fitness_values, new_individuals, new def _perform_migration(self): """执行迁移操作""" - all_migrants = [] + from collections import defaultdict + + migrants_by_destination = defaultdict(list) modified_islands = set() for island_idx, ga_instance in enumerate(self.islands): @@ -248,24 +250,30 @@ def _perform_migration(self): for dest_idx in destinations: modified_islands.add(dest_idx) for migrant_idx, migrant in enumerate(migrants): - all_migrants.append({ + migrants_by_destination[dest_idx].append({ 'source': island_idx, - 'destination': dest_idx, 'individual': migrant.copy(), 'fitness': migrant_fitness[migrant_idx] }) - for migration in all_migrants: - dest_idx = migration['destination'] + for dest_idx, incoming_migrants in migrants_by_destination.items(): dest_ga = self.islands[dest_idx] - dest_fitness = dest_ga.last_generation_fitness + dest_fitness = dest_ga.last_generation_fitness.copy() - self._replace_individuals( - dest_ga, - dest_fitness, - [migration['individual']], - [migration['fitness']] - ) + new_individuals = [m['individual'] for m in incoming_migrants] + new_fitness = [m['fitness'] for m in incoming_migrants] + + num_to_replace = min(len(new_individuals), len(dest_fitness)) + + if self.replacement == 'worst': + sorted_indices = numpy.argsort(dest_fitness) + replace_indices = sorted_indices[:num_to_replace] + else: + replace_indices = random.sample(range(len(dest_fitness)), num_to_replace) + + for i, idx in enumerate(replace_indices): + if i < len(new_individuals): + dest_ga.population[idx] = new_individuals[i].copy() for island_idx in modified_islands: self.islands[island_idx].last_generation_fitness = self.islands[island_idx].cal_pop_fitness() diff --git a/tests/test_islandga.py b/tests/test_islandga.py index fd1ff49..f141057 100644 --- a/tests/test_islandga.py +++ b/tests/test_islandga.py @@ -541,6 +541,76 @@ def test_fully_connected_topology_paths(): print(" ✓ 全连接拓扑路径正确 (每个岛屿连接到所有其他岛屿)") +def test_multiple_sources_to_single_destination_no_overwrite(): + """ + 关键测试：验证全连接拓扑下多个源岛向同一个目标岛迁移时， + 移民不会互相覆盖。 + + 测试逻辑： + 1. 创建 4 个岛屿，全连接拓扑 + 2. 在岛屿 0、1、2 中分别放入具有唯一标识的高适应度个体 + 3. 执行一次迁移，这 3 个岛的移民都会进入岛屿 3 + 4. 验证岛屿 3 的种群中确实存在这 3 个不同的移民， + 而不是只保留最后到达的那一个 + """ + print("\n测试: 多源到单目标迁移不覆盖...") + + island_ga = pygad.IslandGA( + num_islands=4, + num_generations=5, + num_parents_mating=2, + fitness_func=fitness_func, + sol_per_pop=10, + num_genes=4, + migration_frequency=10, + num_migrants=1, + migration_topology='fully_connected', + migrant_selection='best', + replacement='worst', + random_seed=random_seed, + suppress_warnings=True + ) + + for ga_instance in island_ga.islands: + ga_instance.initialize_population( + allow_duplicate_genes=ga_instance.allow_duplicate_genes, + gene_type=ga_instance.gene_type, + gene_constraint=ga_instance.gene_constraint + ) + + unique_solution_0 = numpy.array([100.0, 0.0, 0.0, 0.0]) + unique_solution_1 = numpy.array([0.0, 100.0, 0.0, 0.0]) + unique_solution_2 = numpy.array([0.0, 0.0, 100.0, 0.0]) + + island_ga.islands[0].population[0] = unique_solution_0.copy() + island_ga.islands[1].population[0] = unique_solution_1.copy() + island_ga.islands[2].population[0] = unique_solution_2.copy() + + for i in range(4): + island_ga.islands[i].last_generation_fitness = island_ga.islands[i].cal_pop_fitness() + + island_3_before = [list(sol) for sol in island_ga.islands[3].population] + + island_ga._perform_migration() + + island_3_after = [list(sol) for sol in island_ga.islands[3].population] + + found_0 = any(numpy.allclose(sol, unique_solution_0, atol=1e-10) for sol in island_ga.islands[3].population) + found_1 = any(numpy.allclose(sol, unique_solution_1, atol=1e-10) for sol in island_ga.islands[3].population) + found_2 = any(numpy.allclose(sol, unique_solution_2, atol=1e-10) for sol in island_ga.islands[3].population) + + found_count = sum([found_0, found_1, found_2]) + + print(f" 岛屿 3 迁移前种群:\n {[list(s) for s in island_3_before[:3]]}...") + print(f" 岛屿 3 迁移后种群 (前5个):\n {[list(s) for s in island_ga.islands[3].population[:5]]}") + print(f" 找到的唯一移民: 岛屿0={found_0}, 岛屿1={found_1}, 岛屿2={found_2}") + + assert found_count >= 2, \ + f"全连接拓扑下 3 个源岛向目标岛迁移，至少应该找到 2 个不同的移民，但只找到 {found_count} 个。" \ + f"这说明移民可能被覆盖了！" + + print(" ✓ 多源到单目标迁移无覆盖问题") + if __name__ == "__main__": print("=" * 60) print("IslandGA 单元测试") @@ -560,6 +630,7 @@ def test_fully_connected_topology_paths(): test_ring_topology_paths() test_star_topology_paths() test_fully_connected_topology_paths() + test_multiple_sources_to_single_destination_no_overwrite() print("\n" + "=" * 60) print("所有测试通过! ✓")