修改了 ortools 中的总线调度问题



我想从ortools修改总线调度问题,以便每个驾驶员的班次在插槽方面是连续的,并且如果需要,驾驶员可以同时共享一个班次。

例如,假设我们有以下半小时轮班(格式类似于ortools的原始bus_scheduling_problem):

shifts = [
[0, '07:00', '07:30', 420, 450, 30],
[1, '07:30', '08:00', 450, 480, 30],
[2, '08:00', '08:30', 480, 510, 30],
[3, '08:30', '09:00', 510, 540, 30],
[4, '09:00', '09:30', 540, 570, 30],
[5, '09:30', '10:00', 570, 600, 30],
[6, '10:00', '10:30', 600, 630, 30],
[7, '10:30', '11:00', 630, 660, 30],
[8, '11:00', '11:30', 660, 690, 30],
[9, '11:30', '12:00', 690, 720, 30],
[10, '12:00', '12:30', 720, 750, 30],
[11, '12:30', '13:00', 750, 780, 30],
[12, '13:00', '13:30', 780, 810, 30],
[13, '13:30', '14:00', 810, 840, 30],
[14, '14:00', '14:30', 840, 870, 30],
[15, '14:30', '15:00', 870, 900, 30],
[16, '15:00', '15:30', 900, 930, 30],
[17, '15:30', '16:00', 930, 960, 30],
[18, '16:00', '16:30', 960, 990, 30],
[19, '16:30', '17:00', 990, 1020, 30],
[20, '17:00', '17:30', 1020, 1050, 30],
[21, '17:30', '18:00', 1050, 1080, 30],
[22, '18:00', '18:30', 1080, 1110, 30],
[23, '18:30', '19:00', 1110, 1140, 30],
[24, '19:00', '19:30', 1140, 1170, 30],
[25, '19:30', '20:00', 1170, 1200, 30],
[26, '20:00', '20:30', 1200, 1230, 30],
[27, '20:30', '21:00', 1230, 1260, 30],
[28, '21:00', '21:30', 1260, 1290, 30],
[29, '21:30', '22:00', 1290, 1320, 30],
[30, '22:00', '22:30', 1320, 1350, 30],
[31, '22:30', '23:00', 1350, 1380, 30],
[32, '23:00', '23:30', 1380, 1410, 30],
[33, '23:30', '24:00', 1410, 1440, 30]
]

我成功执行了此版本的bus_scheduling代码,我发现我需要 2 个驱动程序来满足上述时间表的需求。工作时间范围从07:00 am to 24:00 (midnight).

因此,如果我们有 2 名公交车司机参加这个时间表,我更喜欢一个涵盖基于 12 小时司机班次的日常职责的分配,如下所示:

Driver 1: 07:00 - 19:00 with a break at 13:00
Driver 2: 12:00 - 24:00 with a break at 14:00 (basically no overlap with Driver 1's break)

我所说的连续小时是指以07:00-11:00 + 14:00-15:00 + 17:00-24:00形式满足12 小时驾驶员换档解决方案的解决方案是不可接受的。具有更多驱动程序的解决方案还应确保中断不会重叠,以免所有驱动程序都处于休息状态。此外,由于高工作负载,可能会阻塞休息槽。

我在or-tools 讨论中得到了一个答案,说我需要在每个节点上维护自轮班开始以来的总时间,但我在编码时遇到困难,假设它解决了我的问题。

对我来说,ortools 的总线调度问题对您的任务来说是矫枉过正,因为您提到轮班时间总是30分钟,不需要设置/清理时间。此外,司机必须工作11小时并连续休息。相反,我们可以编写一个类似于护士调度问题的脚本,它可能更容易理解(对我来说,这是第一次使用or-tools编写东西,而且很清楚)。

制备

首先,班次总数可以计算如下:

num_shifts = len(shifts)

所需驱动程序数量:

num_drivers = ceil(float(num_shifts) / working_time)

在您的情况下,驾驶员必须整整驾驶11小时,因此22班次(每个班次固定为30分钟):

working_time = 22

休息时间为1小时,因此:

break_time = 2

正如您在评论中提到的,每个司机必须在驾驶4小时后休息,但不迟于8小时后:

break_interval = [8, 16]

驾驶员可以开始工作的最新班次:

latest_start_shift = num_shifts - working_time - break_time

真的,如果他/她稍后开始工作,那么司机将不会在全部工作时间工作。

构建模型

让我们为驱动程序定义一组班次:

driver_shifts = {}
for driver_id in range(num_drivers):
for shift_id in range(num_shifts):
driver_shifts[(driver_id, shift_id)] = model.NewBoolVar('driver%ishift%i' % (driver_id, shift_id))

如果将换档s分配给驾驶员d,则driver_shifts[(d, s)]等于1,否则0

此外,为驾驶员创建一组开始班次:

start_time = {}
for driver_id in range(num_drivers):
for shift_id in range(latest_start_shift + 1):
start_time[(driver_id, shift_id)] = model.NewBoolVar('driver%istart%i' % (driver_id, shift_id))

如果司机ds班开始工作日,start_time[(d, s)]等于1,否则0

司机每天行驶 11 小时

每位司机必须在一天内准确驾驶所需的驾驶时间:

for driver_id in range(num_drivers):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for shift_id in range(num_shifts)) == working_time)

但是,这还不够,因为驾驶员必须在中间连续进行一次休息。稍后我们将看到如何执行此操作。

所有班次均由司机负责

每个班次必须由至少一名驾驶驾驶员负责:

for shift_id in range(num_shifts):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for driver_id in range(num_drivers)) >= 1)

驾驶员连续行驶

在这里,start_time发挥作用。基本思想是,对于驱动程序的每个可能的开始时间,我们强制驱动程序在时间之外工作(物理上,驱动程序只能开始工作一次!

因此,驾驶员每天只能开始工作一次:

for driver_id in range(num_drivers):
model.Add(sum(start_time[(driver_id, start_shift_id)] for start_shift_id in range(latest_start_shift + 1)) == 1)

对于驾驶员的每个开始时间,连续working_time + break_time内的工作时间working_time

for driver_id in range(num_drivers):
for start_shift_id in range(latest_start_shift + 1):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for shift_id in
range(start_shift_id, start_shift_id + working_time + break_time)) == working_time) 
.OnlyEnforceIf(start_time[(driver_id, start_shift_id)]) 

中断是连续的

为此,我们需要一个额外的数组break_ind[(d, s, b)],表示给定的驾驶员是否d给定的工作班次开始s在班次b休息。因此,在这种情况下,应在中断时0driver_shifts值:

l = start_shift_id + break_interval[0]
r = start_shift_id + break_interval[1]
for s in range(l, r):
break_ind[(driver_id, start_shift_id, s)] = model.NewBoolVar("d%is%is%i"%(driver_id, start_shift_id, s))
model.Add(sum(driver_shifts[(driver_id, s1)] for s1 in range(s, s + break_time)) == 0)
.OnlyEnforceIf(start_time[(driver_id, start_shift_id)])
.OnlyEnforceIf(break_ind[(driver_id, start_shift_id, s)]) 

此外,司机每天只能休息一次:

model.Add(sum(break_ind[(driver_id, start_shift_id, s)] for s in range(l, r)) == 1)

完整代码

您可以在下面或此处查看完整代码(我添加了它以供将来参考)。在那里,您还可以找到针对驾驶员不休息的情况的简化版本。

from ortools.sat.python import cp_model
from math import ceil
shifts = [
[0, '07:00', '07:30', 420, 450, 30],
[1, '07:30', '08:00', 450, 480, 30],
[2, '08:00', '08:30', 480, 510, 30],
[3, '08:30', '09:00', 510, 540, 30],
[4, '09:00', '09:30', 540, 570, 30],
[5, '09:30', '10:00', 570, 600, 30],
[6, '10:00', '10:30', 600, 630, 30],
[7, '10:30', '11:00', 630, 660, 30],
[8, '11:00', '11:30', 660, 690, 30],
[9, '11:30', '12:00', 690, 720, 30],
[10, '12:00', '12:30', 720, 750, 30],
[11, '12:30', '13:00', 750, 780, 30],
[12, '13:00', '13:30', 780, 810, 30],
[13, '13:30', '14:00', 810, 840, 30],
[14, '14:00', '14:30', 840, 870, 30],
[15, '14:30', '15:00', 870, 900, 30],
[16, '15:00', '15:30', 900, 930, 30],
[17, '15:30', '16:00', 930, 960, 30],
[18, '16:00', '16:30', 960, 990, 30],
[19, '16:30', '17:00', 990, 1020, 30],
[20, '17:00', '17:30', 1020, 1050, 30],
[21, '17:30', '18:00', 1050, 1080, 30],
[22, '18:00', '18:30', 1080, 1110, 30],
[23, '18:30', '19:00', 1110, 1140, 30],
[24, '19:00', '19:30', 1140, 1170, 30],
[25, '19:30', '20:00', 1170, 1200, 30],
[26, '20:00', '20:30', 1200, 1230, 30],
[27, '20:30', '21:00', 1230, 1260, 30],
[28, '21:00', '21:30', 1260, 1290, 30],
[29, '21:30', '22:00', 1290, 1320, 30],
[30, '22:00', '22:30', 1320, 1350, 30],
[31, '22:30', '23:00', 1350, 1380, 30],
[32, '23:00', '23:30', 1380, 1410, 30],
[33, '23:30', '24:00', 1410, 1440, 30]
]
class VarArraySolutionPrinter(cp_model.CpSolverSolutionCallback):
def __init__(self, driver_shifts, num_drivers, num_shifts, solutions):
cp_model.CpSolverSolutionCallback.__init__(self)
self.driver_shifts = driver_shifts
self.num_drivers = num_drivers
self.num_shifts = num_shifts
self.solutions = solutions
self.solution_id = 0
def on_solution_callback(self):
if self.solution_id in self.solutions:
self.solution_id += 1
print ("Solution found!")
for driver_id in range(self.num_drivers):
print ("*************Driver#%s*************" % driver_id)
for shift_id in range(self.num_shifts):
if (self.Value(self.driver_shifts[(driver_id, shift_id)])):
print('Shift from %s to %s' %
(shifts[shift_id][1],
shifts[shift_id][2]))
print()
def solution_count(self):
return self.solution_id
solver = cp_model.CpSolver()
model = cp_model.CpModel()
num_shifts = len(shifts)
working_time = 22
break_time = 2
# when take a break within the working time
break_interval = [8, 16]
latest_start_shift = num_shifts - working_time - break_time
num_drivers = ceil(float(num_shifts) / working_time)
# create an array of assignments of drivers
driver_shifts = {}
for driver_id in range(num_drivers):
for shift_id in range(num_shifts):
driver_shifts[(driver_id, shift_id)] = model.NewBoolVar('driver%ishift%i' % (driver_id, shift_id))
# driver must work exactly {working_time} shifts
for driver_id in range(num_drivers):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for shift_id in range(num_shifts)) == working_time)
# each shift must be covered by at least one driver
for shift_id in range(num_shifts):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for driver_id in range(num_drivers)) >= 1)
# create an array of start times for drivers
start_time = {}
for driver_id in range(num_drivers):
for shift_id in range(latest_start_shift + 1):
start_time[(driver_id, shift_id)] = model.NewBoolVar('driver%istart%i' % (driver_id, shift_id))
break_ind = {}
for driver_id in range(num_drivers):
for start_shift_id in range(latest_start_shift + 1):
model.Add(sum(driver_shifts[(driver_id, shift_id)] for shift_id in
range(start_shift_id, start_shift_id + working_time + break_time)) == working_time) 
.OnlyEnforceIf(start_time[(driver_id, start_shift_id)])
l = start_shift_id + break_interval[0]
r = start_shift_id + break_interval[1]
for s in range(l, r):
break_ind[(driver_id, start_shift_id, s)] = model.NewBoolVar("d%is%is%i"%(driver_id, start_shift_id, s))
model.Add(sum(driver_shifts[(driver_id, s1)] for s1 in range(s, s + break_time)) == 0)
.OnlyEnforceIf(start_time[(driver_id, start_shift_id)])
.OnlyEnforceIf(break_ind[(driver_id, start_shift_id, s)])
model.Add(sum(break_ind[(driver_id, start_shift_id, s)] for s in range(l, r)) == 1)
for driver_id in range(num_drivers):
model.Add(sum(start_time[(driver_id, start_shift_id)] for start_shift_id in range(latest_start_shift + 1)) == 1)
solution_printer = VarArraySolutionPrinter(driver_shifts, num_drivers, num_shifts, range(2))
status = solver.SearchForAllSolutions(model, solution_printer)

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