我需要帮助在 SimPy 中模拟火车系统(如地铁系统)，问题是我的“模拟”老师要我使用 Python + SimPy 而我不知道如何使用它，经过一周阅读 SimPy 我设法理解了银行的例子，这很容易，但现在我仍然不知道如何建模老师给我的问题......
问题很大而且范围很广，但我只需要一点帮助，而不是完成整个项目，所以，如果有人能提供帮助，我将不胜感激。
将帮助我开始的减少的问题是这样的:
假设您有 3 个车站(A、B、C)，相隔一定距离(比如说 100 米)，我有 2 列火车，一列在 A 上，一列在 C 上(火车 1 从 A 到 C，tran2 从 C 到A)每列火车都有最大速度(假设两者均为 50m/s)和加速度(假设为 5m/s^2 和 -5m/s^2 用于中断)，他们所要做的就是在每个车站停下来几秒钟(比如说 24 秒)，然后继续到下一站，当他们到达终点时，他们等待额外的 20 秒(换轨)，然后重新开始。
车站有乘客数量限制(不需要模拟)，唯一的问题是每个车站都有随机数量的乘客，当火车到达时，有些人站起来，有些人下来...
所以，基本上我需要一个小火车模型和带有这 3 个车站的车站...如果有人可以帮助我...
真正的问题有 22 个车站、2 个额外的变道车站、随机等待时间、42 列具有不同最大速度和载客量的列车、根据车站和一天中的时间产生的不同乘客数量等等……所有这些东西我可以稍后管理，但是火车站系统的建模逻辑我似乎无法弄清楚......谢谢你的帮助!
最佳答案
我绝不是 SimPy 的专家，但这应该可以帮助您入门:
"""
Simulation of a train network
"""
from SimPy.Simulation import *
from math import sqrt
from random import randint
from itertools import cycle
def timeTo(A, maxV, d):
"""
Given a trapezoidal velocity envelope defined by
A constant acceleration, m/s/s
maxV maximumum velocity, m/s
return time in seconds required to travel
d distance, m
"""
tA = float(maxV)/A # time to accelerate to maxV
dA = A*tA*tA # distance traveled during acceleration from 0 to maxV and back to 0
if (d < dA): # train never reaches full speed?
return sqrt(4.0*d/A) # time needed to accelerate to half-way point then decelerate to destination
else:
return 2*tA + (d-dA)/maxV # time to accelerate to maxV plus travel at maxV plus decelerate to destination
class Train(Process):
def __init__(self, name, sim, accel=1.0, maxV=50.0, passengers=0, maxPassengers=400):
super(Train, self).__init__(name, sim)
self.accel = accel
self.maxV = maxV
self.p = passengers
self.maxP = maxPassengers
def roll(self, route):
here = route.next() # starting location
for dest in route:
# travel to next station
print "{:.1f}s: {} leaving {} for {}".format(self.sim.now(), self.name, here, dest)
yield hold, self, timeTo(self.accel, self.maxV, here.distanceTo[dest])
# arrive at next station
here = dest
print "{:.1f}s: {} at {}".format(self.sim.now(), self.name, here)
yield hold, self, here.arrive(self)
def getOff(self, num):
if self.p >= num:
print " {} passengers got off".format(num)
self.p -= num
else:
num = self.p
print " train is empty - only {} passengers got off".format(num)
self.p = 0
def getOn(self, num):
if (self.maxP is None) or (self.p + num <= self.maxP):
print " {} passengers got on".format(num)
self.p += num
else:
num = self.maxp - self.p
print " train is full - only {} passengers got on".format(num)
self.p = self.maxp
class TrackNode(object):
def __init__(self, name, delay=5.0):
self.name = name
self.delay = delay
self.distanceTo = {}
def arrive(self, train):
pass
def __str__(self):
return self.name
class Station(TrackNode):
def arrive(self, train):
train.getOff(randint(1,15))
train.getOn(randint(1,15))
return self.delay
class Switch(TrackNode):
def arrive(self, train):
print(" switching tracks")
return self.delay
class SampleRailroad(Simulation):
def run(self, maxTime=100.0):
self.initialize()
# create places
x = Switch("switch x", 20.0)
A = Station("Station A", 24.0)
B = Station("Station B", 27.0)
C = Station("Station C", 25.0)
y = Switch("switch y", 18.0)
# distances between places
x.distanceTo[A] = 50.0
A.distanceTo[B] = 5000.0
B.distanceTo[C] = 2000.0
C.distanceTo[y] = 80.0
y.distanceTo[C] = 80.0
C.distanceTo[B] = 2000.0
B.distanceTo[A] = 5000.0
A.distanceTo[x] = 50.0
# set up first train
sf = Train("Santa Fe 219", self)
self.activate(sf, sf.roll(cycle([A,B,C,y,C,B,A,x])), at=0.0)
# set up second train
cn = Train("Canadian National 41", self, maxPassengers=200)
self.activate(cn, cn.roll(cycle([C,B,A,x,A,B,C,y])), at=5.0)
# start simulating!
self.simulate(until=maxTime)
def main():
rr = SampleRailroad()
rr.run(800.0)
if __name__=="__main__":
main()
关于python - 需要帮助使用 SimPy 对火车系统进行建模，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/9472342/