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-rw-r--r--multiple_ant_colony_system.py84
1 files changed, 57 insertions, 27 deletions
diff --git a/multiple_ant_colony_system.py b/multiple_ant_colony_system.py
index b292072..9a9dcb1 100644
--- a/multiple_ant_colony_system.py
+++ b/multiple_ant_colony_system.py
@@ -7,6 +7,7 @@ from threading import Thread, Event
from queue import Queue
from concurrent.futures import ThreadPoolExecutor
import copy
+import time
class MultipleAntColonySystem:
@@ -58,7 +59,7 @@ class MultipleAntColonySystem:
return index_to_visit[ind]
@staticmethod
- def new_active_ant(ant: Ant, vehicle_num: int, local_search: bool, IN: np.numarray, q0: float, stop_event: Event):
+ def new_active_ant(ant: Ant, vehicle_num: int, local_search: bool, IN: np.numarray, q0: float, beta: int, stop_event: Event):
# print('[new_active_ant]: start, start_index %d' % ant.travel_path[0])
# 在new_active_ant中,最多可以使用vehicle_num个车,即最多可以包含vehicle_num+1个depot结点,由于出发结点用掉了一个,所以只剩下vehicle个depot
@@ -96,13 +97,18 @@ class MultipleAntColonySystem:
distance = np.array([max(1.0, j) for j in distance-IN[next_index_meet_constrains]])
closeness = 1/distance
+ transition_prob = ant.graph.pheromone_mat[ant.current_index][next_index_meet_constrains] * \
+ np.power(closeness, beta)
+
+ transition_prob = transition_prob / np.sum(transition_prob)
+
# 按照概率直接选择closeness最大的结点
if np.random.rand() < q0:
- max_prob_index = np.argmax(closeness)
+ max_prob_index = np.argmax(transition_prob)
next_index = next_index_meet_constrains[max_prob_index]
else:
# 使用轮盘赌算法
- next_index = MultipleAntColonySystem.stochastic_accept(next_index_meet_constrains, closeness)
+ next_index = MultipleAntColonySystem.stochastic_accept(next_index_meet_constrains, transition_prob)
# 更新信息素矩阵
ant.graph.local_update_pheromone(ant.current_index, next_index)
@@ -120,7 +126,9 @@ class MultipleAntColonySystem:
ant.local_search_procedure(stop_event)
@staticmethod
- def acs_time(new_graph: VrptwGraph, vehicle_num, ants_num, q0, global_path_queue: Queue, path_found_queue: Queue, stop_event: Event):
+ def acs_time(new_graph: VrptwGraph, vehicle_num: int, ants_num: int, q0: float, beta: int,
+ global_path_queue: Queue, path_found_queue: Queue, stop_event: Event):
+
# 最多可以使用vehicle_num辆车,即在path中最多包含vehicle_num+1个depot中,找到路程最短的路径,
# vehicle_num设置为与当前的best_path一致
print('[acs_time]: start, vehicle_num %d' % vehicle_num)
@@ -138,7 +146,8 @@ class MultipleAntColonySystem:
for k in range(ants_num):
ant = Ant(new_graph, 0)
- thread = ants_pool.submit(MultipleAntColonySystem.new_active_ant, ant, vehicle_num, True, np.zeros(new_graph.node_num), q0, stop_event)
+ thread = ants_pool.submit(MultipleAntColonySystem.new_active_ant, ant, vehicle_num, True,
+ np.zeros(new_graph.node_num), q0, beta, stop_event)
ants_thread.append(thread)
ants.append(ant)
@@ -154,14 +163,15 @@ class MultipleAntColonySystem:
print('[acs_time]: receive stop event')
return
- # 如果比全局的路径要好,则要将该路径发送到macs中
+ # 获取当前的best path
if not global_path_queue.empty():
info = global_path_queue.get()
while not global_path_queue.empty():
info = global_path_queue.get()
print('[acs_time]: receive global path info')
- global_best_path, global_best_distance = info.get_path_info()
+ global_best_path, global_best_distance, global_used_vehicle_num = info.get_path_info()
+ # 如果比全局的路径要好,则要将该路径发送到macs中
if ant.index_to_visit_empty() and ant.total_travel_distance < global_best_distance:
print('[acs_time]: found a improved feasible path, send path info to macs')
path_found_queue.put(PathMessage(ant.travel_path, ant.total_travel_distance))
@@ -170,15 +180,17 @@ class MultipleAntColonySystem:
new_graph.global_update_pheromone(global_best_path, global_best_distance)
@staticmethod
- def acs_vehicle(new_graph: VrptwGraph, vehicle_num: int, ants_num: int, q0: float, global_path_queue: Queue, path_found_queue: Queue, stop_event: Event):
+ def acs_vehicle(new_graph: VrptwGraph, vehicle_num: int, ants_num: int, q0: float, beta: int,
+ global_path_queue: Queue, path_found_queue: Queue, stop_event: Event):
+
# 最多可以使用vehicle_num辆车,即在path中最多包含vehicle_num+1个depot中,找到路程最短的路径,
# vehicle_num设置为比当前的best_path少一个
print('[acs_vehicle]: start, vehicle_num %d' % vehicle_num)
global_best_path = None
global_best_distance = None
- # 使用邻近点算法初始化path 和distance
- current_path, current_path_distance = new_graph.nearest_neighbor_heuristic()
+ # 使用nearest_neighbor_heuristic算法初始化path 和distance
+ current_path, current_path_distance, _ = new_graph.nearest_neighbor_heuristic()
# 找出当前path中未访问的结点
current_index_to_visit = list(range(new_graph.node_num))
@@ -197,7 +209,8 @@ class MultipleAntColonySystem:
for k in range(ants_num):
ant = Ant(new_graph, 0)
- thread = ants_pool.submit(MultipleAntColonySystem.new_active_ant, ant, vehicle_num, True, IN, q0, stop_event)
+ thread = ants_pool.submit(MultipleAntColonySystem.new_active_ant, ant, vehicle_num, True, IN, q0,
+ beta, stop_event)
ants_thread.append(thread)
ants.append(ant)
@@ -215,7 +228,7 @@ class MultipleAntColonySystem:
index_to_visit = copy.deepcopy(ant.index_to_visit)
IN[index_to_visit] = IN[index_to_visit]+1
- # 判断蚂蚁找出来的路径是否比current_path,能使用vehicle_num辆车访问到更多的结点
+ # 蚂蚁找出来的路径与current_path进行比较,是否能使用vehicle_num辆车访问到更多的结点
if len(index_to_visit) < len(current_index_to_visit):
current_path = copy.deepcopy(ant.travel_path)
current_index_to_visit = index_to_visit
@@ -236,7 +249,7 @@ class MultipleAntColonySystem:
while not global_path_queue.empty():
info = global_path_queue.get()
print('[acs_vehicle]: receive global path info')
- global_best_path, global_best_distance = info.get_path_info()
+ global_best_path, global_best_distance, global_used_vehicle_num = info.get_path_info()
new_graph.global_update_pheromone(global_best_path, global_best_distance)
@@ -248,7 +261,7 @@ class MultipleAntColonySystem:
# 是否要展示figure
if self.whether_or_not_to_show_figure:
- figure = VrptwAcoFigure(self.graph, path_queue_for_figure)
+ figure = VrptwAcoFigure(self.graph.nodes, path_queue_for_figure)
figure.run()
multiple_ant_colony_system_thread.join()
@@ -265,25 +278,27 @@ class MultipleAntColonySystem:
path_found_queue = Queue()
# 使用近邻点算法初始化
- self.best_path, self.best_path_distance = self.graph.nearest_neighbor_heuristic()
- self.best_vehicle_num = self.best_path.count(0) - 1
+ self.best_path, self.best_path_distance, self.best_vehicle_num = self.graph.nearest_neighbor_heuristic()
while True:
- # 当前best path的信息
+ start_time = time.time()
+
+ # 当前best path的信息,放在queue中以通知acs_time和acs_vehicle当前的best_path是什么
global_path_to_acs_vehicle.put(PathMessage(self.best_path, self.best_path_distance))
global_path_to_acs_time.put(PathMessage(self.best_path, self.best_path_distance))
- # acs_vehicle
stop_event = Event()
+
+ # acs_vehicle,尝试以self.best_vehicle_num-1辆车去探索,访问更多的结点
graph_for_acs_vehicle = self.graph.copy(self.graph.init_pheromone_val)
acs_vehicle_thread = Thread(target=MultipleAntColonySystem.acs_vehicle,
args=(graph_for_acs_vehicle, self.best_vehicle_num-1, self.ants_num, self.q0,
- global_path_to_acs_vehicle, path_found_queue, stop_event))
+ self.beta, global_path_to_acs_vehicle, path_found_queue, stop_event))
- # acs_time
+ # acs_time 尝试以self.best_vehicle_num辆车去探索,找到更短的路径
graph_for_acs_time = self.graph.copy(self.graph.init_pheromone_val)
acs_time_thread = Thread(target=MultipleAntColonySystem.acs_time,
- args=(graph_for_acs_time, self.best_vehicle_num, self.ants_num, self.q0,
+ args=(graph_for_acs_time, self.best_vehicle_num, self.ants_num, self.q0, self.beta,
global_path_to_acs_time, path_found_queue, stop_event))
# 启动acs_vehicle_thread和acs_time_thread,当他们找到feasible、且是比best path好的路径时,就会发送到macs中来
@@ -295,20 +310,31 @@ class MultipleAntColonySystem:
while acs_vehicle_thread.is_alive() and acs_time_thread.is_alive():
+ # 如果在指定时间内没有搜索到更好的结果,则退出程序
+ end_time = time.time()
+ if end_time - start_time > 60 * 5:
+ stop_event.set()
+ print('time is up: cannot find a better solution in given time')
+ return
+
if path_found_queue.empty():
continue
path_info = path_found_queue.get()
print('[macs]: receive found path info')
- found_path, found_path_distance = path_info.get_path_info()
+ found_path, found_path_distance, found_path_used_vehicle_num = path_info.get_path_info()
- # 如果找到的路径(feasible)的距离更短,则更新当前的最佳path的信息
+ # 如果找到的路径(which is feasible)的距离更短,则更新当前的最佳path的信息
if found_path_distance < self.best_path_distance:
+
+ # 搜索到更好的结果,更新start_time
+ start_time = time.time()
+
print('-' * 50)
print('[macs]: distance of found path (%f) better than best path\'s (%f)' % (found_path_distance, self.best_path_distance))
print('-' * 50)
self.best_path = found_path
- self.best_vehicle_num = found_path.count(0) - 1
+ self.best_vehicle_num = found_path_used_vehicle_num
self.best_path_distance = found_path_distance
# 如果需要绘制图形,则要找到的best path发送给绘图程序
@@ -321,12 +347,16 @@ class MultipleAntColonySystem:
# 如果,这两个线程找到的路径用的车辆更少了,就停止这两个线程,开始下一轮迭代
# 向acs_time和acs_vehicle中发送停止信息
- if found_path.count(0)-1 < best_vehicle_num:
+ if found_path_used_vehicle_num < best_vehicle_num:
+
+ # 搜索到更好的结果,更新start_time
+ start_time = time.time()
+
print('-' * 50)
- print('[macs]: vehicle num of found path (%d) better than best path\'s (%d)' % (found_path.count(0)-1, best_vehicle_num))
+ print('[macs]: vehicle num of found path (%d) better than best path\'s (%d)' % (found_path_used_vehicle_num, best_vehicle_num))
print('-' * 50)
self.best_path = found_path
- self.best_vehicle_num = found_path.count(0)-1
+ self.best_vehicle_num = found_path_used_vehicle_num
self.best_path_distance = found_path_distance
if self.whether_or_not_to_show_figure: