翻译这段代码:def checkTimeWindow(route,model,vehicle): timetable=[] departure=0 for i in range(len(route)): if i == 0: next_node_id = route[i + 1] travel_time = int(model.distance_matrix[vehicle.type, next_node_id] /vehicle.free_speed) departure = max(0, model.demand_dict[next_node_id].start_time - travel_time) #下一个节点开始时间减去旅行时间 timetable.append((int(departure), int(departure))) elif 1 <= i <= len(route) - 2: last_node_id = route[i - 1] current_node_id = route[i] current_node = model.demand_dict[current_node_id] travel_time = int(model.distance_matrix[last_node_id, current_node_id] / vehicle.free_speed) arrival = max(timetable[-1][1] + travel_time, current_node.start_time) departure = arrival + current_node.service_time timetable.append((int(arrival), int(departure))) if departure > current_node.end_time: departure = float('inf') break else: last_node_id = route[i - 1] travel_time = int(model.distance_matrix[last_node_id, vehicle.type] / vehicle.free_speed) departure = timetable[-1][1] + travel_time timetable.append((int(departure), int(departure))) if departure<vehicle.end_time: return True else: return False
时间: 2024-04-26 16:20:06 浏览: 179
这段代码实现了一个名为checkTimeWindow的函数,接受三个参数route、model和vehicle。其中,route是一个表示路径的列表,model是一个包含距离矩阵和需求字典的对象,vehicle是一个包含车辆类型和结束时间的对象。
函数的主要功能是检查给定路径上所有节点的时间窗口是否合法,若合法则返回True,否则返回False。
函数首先创建了一个空列表timetable,然后遍历路径中的所有节点。对于第一个节点,它计算出到下一个节点的旅行时间,并将出发时间设为到达时间和该节点开始时间的最大值,然后将该节点的到达时间和出发时间加入到timetable中。
对于路径中的中间节点,函数计算出到达时间和出发时间,并将它们加入到timetable中。如果出发时间超出了节点的结束时间,则将出发时间设为无穷大并退出循环。对于最后一个节点,函数计算出到达时间并将其加入到timetable中。
最后,函数检查最后一个节点的出发时间是否早于车辆的结束时间,若是则返回True,否则返回False。
相关问题
优化这段代码:def checkTimeWindow(route,model,vehicle): timetable=[] departure=0 for i in range(len(route)): if i == 0: next_node_id = route[i + 1] travel_time = int(model.distance_matrix[vehicle.type, next_node_id] /vehicle.free_speed) departure = max(0, model.demand_dict[next_node_id].start_time - travel_time) timetable.append((int(departure), int(departure))) elif 1 <= i <= len(route) - 2: last_node_id = route[i - 1] current_node_id = route[i] current_node = model.demand_dict[current_node_id] travel_time = int(model.distance_matrix[last_node_id, current_node_id] / vehicle.free_speed) arrival = max(timetable[-1][1] + travel_time, current_node.start_time) departure = arrival + current_node.service_time timetable.append((int(arrival), int(departure))) if departure > current_node.end_time: departure = float('inf') break else: last_node_id = route[i - 1] travel_time = int(model.distance_matrix[last_node_id, vehicle.type] / vehicle.free_speed) departure = timetable[-1][1] + travel_time timetable.append((int(departure), int(departure))) if departure<vehicle.end_time: return True else: return False
可以考虑以下优化方法:
1. 将 `range(len(route))` 提取为一个变量 `n`,这样可以减少多次计算 `len(route)` 的开销。
2. 将 `model.distance_matrix[vehicle.type, next_node_id]` 提取为一个变量 `dist1`,将 `model.distance_matrix[last_node_id, current_node_id]` 提取为一个变量 `dist2`,将 `model.distance_matrix[last_node_id, vehicle.type]` 提取为一个变量 `dist3`,这样可以减少多次计算距离的开销。
3. 将 `departure` 的类型由浮点型改为整型,这样可以避免浮点数精度误差产生的问题。
4. 将 `timetable` 中元素的类型由元组 `(int, int)` 改为列表 `[int, int]`,这样可以减少元组解包的开销。
优化后的代码如下:
```
def check_time_window(route, model, vehicle):
timetable = []
departure = 0
n = len(route)
for i in range(n):
if i == 0:
next_node_id = route[i + 1]
dist1 = model.distance_matrix[vehicle.type, next_node_id]
travel_time = int(dist1 / vehicle.free_speed)
departure = max(0, model.demand_dict[next_node_id].start_time - travel_time)
timetable.append([departure, departure])
elif 1 <= i <= n - 2:
last_node_id = route[i - 1]
current_node_id = route[i]
current_node = model.demand_dict[current_node_id]
dist2 = model.distance_matrix[last_node_id, current_node_id]
travel_time = int(dist2 / vehicle.free_speed)
arrival = max(timetable[-1][1] + travel_time, current_node.start_time)
departure = arrival + current_node.service_time
timetable.append([arrival, departure])
if departure > current_node.end_time:
departure = float('inf')
break
else:
last_node_id = route[i - 1]
dist3 = model.distance_matrix[last_node_id, vehicle.type]
travel_time = int(dist3 / vehicle.free_speed)
departure = timetable[-1][1] + travel_time
timetable.append([departure, departure])
if departure < vehicle.end_time:
return True
else:
return False
```
这样,可以减少重复计算的开销,使得代码更加高效。
降低这段代码的重复率:def checkTimeWindow(route,model,vehicle): timetable=[] departure=0 for i in range(len(route)): if i == 0: next_node_id = route[i + 1] travel_time = int(model.distance_matrix[vehicle.type, next_node_id] /vehicle.free_speed) departure = max(0, model.demand_dict[next_node_id].start_time - travel_time) timetable.append((int(departure), int(departure))) elif 1 <= i <= len(route) - 2: last_node_id = route[i - 1] current_node_id = route[i] current_node = model.demand_dict[current_node_id] travel_time = int(model.distance_matrix[last_node_id, current_node_id] / vehicle.free_speed) arrival = max(timetable[-1][1] + travel_time, current_node.start_time) departure = arrival + current_node.service_time timetable.append((int(arrival), int(departure))) if departure > current_node.end_time: departure = float('inf') break else: last_node_id = route[i - 1] travel_time = int(model.distance_matrix[last_node_id, vehicle.type] / vehicle.free_speed) departure = timetable[-1][1] + travel_time timetable.append((int(departure), int(departure))) if departure<vehicle.end_time: return True else: return False
可以将重复的代码提取出来,封装成一个函数,如下所示:
```python
def get_travel_time(model, vehicle, start_node_id, end_node_id):
return int(model.distance_matrix[start_node_id, end_node_id] / vehicle.free_speed)
def checkTimeWindow(route, model, vehicle):
timetable = []
departure = 0
for i, node_id in enumerate(route):
if i == 0:
next_node_id = route[i + 1]
travel_time = get_travel_time(model, vehicle, vehicle.type, next_node_id)
departure = max(0, model.demand_dict[next_node_id].start_time - travel_time)
timetable.append((int(departure), int(departure)))
elif 1 <= i <= len(route) - 2:
last_node_id = route[i - 1]
current_node = model.demand_dict[node_id]
travel_time = get_travel_time(model, vehicle, last_node_id, node_id)
arrival = max(timetable[-1][1] + travel_time, current_node.start_time)
departure = arrival + current_node.service_time
timetable.append((int(arrival), int(departure)))
if departure > current_node.end_time:
departure = float('inf')
break
else:
last_node_id = route[i - 1]
travel_time = get_travel_time(model, vehicle, last_node_id, vehicle.type)
departure = timetable[-1][1] + travel_time
timetable.append((int(departure), int(departure)))
if departure >= vehicle.end_time:
return False
return True
```
这样,代码中的重复率就降低了。
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