Python卡在多线程程序的单线程中

Question

I'm currently writing a program that is attempting to synchronize a visitor, car, pump, and gas station thread at a zoo where guests arrive, wait for an available car, take a tour, then exit, the cars must refuel every 5 rides, and the gas station must refuel every time 3 cars are refilled. My tests are with 35 visitors, 6 cars, 5 gas pumps, and a time interval of 2. The program reads a text file with the number of guests, cars, pumps, and a time interval between visitors boarding vehicles, then uses the data to fill a class. I create methods for each thread, then create the threads themselves in main. My problem is that my program gets stuck at 6 vehicles, which is the number specified by the text file, after running my first thread method, visitor_thread, and I cannot tell if any other threads are even running concurrently. I am a total novice at multithreading and python alike, and I'm not sure what the problem is. I have worked on the project for twelve hours straight and have been stuck at this point for the past four hours. In theory, visitor_thread, car_thread, and gas_station_thread should all run concurrently from main, and visitor_thread should have vehicles to work with again after some visitors finish their ride, but I just get stuck with six full cars in an infinite loop within visitor_thread. What is causing this infinite loop and how can I make sure all of my threads are actually running?

My code:

from threading import Thread
from threading import Lock
from threading import Event

event = Event()
lock = Lock()
done = Event()
is_done = 0


class Arguments:
def __init__(self, m_visitors, n_cars, k_pumps, t_time, thread_num, _done):
    self.m_visitors = m_visitors
    self.n_cars = n_cars
    self.k_pumps = k_pumps
    self.t_time = t_time
    self.thread_num = thread_num
    self.done = _done


class Car:
def __init__(self, control, rides, time, in_service, int_cus, in_queue):
    self.control = control
    self.rides = rides
    self.time = time
    self.in_service = in_service
    self.int_cus = int_cus
    self.in_queue = in_queue


class Pump:
def __init__(self, control, in_use, car_num, time):
    self.control = control
    self.in_use = in_use
    self.car_num = car_num
    self.time = time


class PumpQueue:
def __init__(self, pQueue, MAXsize, front, back, size):
    self.q = Lock()
    self.pQueue = pQueue
    self.MAXsize = MAXsize
    self.front = front
    self.back = back
    self.size = size


def visitor_thread(_visitor):
global is_done
visitor = _visitor

v = visitor.m_visitors
c = visitor.n_cars
p = visitor.k_pumps
t = visitor.t_time
id = visitor.thread_num

i = 0
j = 0
while i < v:
    for j in range(0, c):
        lock.acquire()
        if cars[j].in_service is False and cars[j].rides < 5:
            print('\nVisitor %d is currently in car %d' % (i+1, j+1))
            cars[j].in_service = True
            i += 1
            print('\n%d customers waiting for a ride.' % (v - i))
            lock.release()
            break
        lock.release()
lock.acquire()
is_done += 1
lock.release()


def car_thread(_car):
global is_done
carThread = _car
cars_done = 0

v = carThread.m_visitors
c = carThread.n_cars
p = carThread.k_pumps
t = carThread.t_time
id = carThread.thread_num
i = 0

while cars_done == 0:
    cars_in_service = 0
    while i < c:
        lock.acquire()
        if cars[i].in_service is True and cars[i].rides < 5:
            # Car still being used, add more time
            cars[i].time += 1
        if cars[i].time == t:
            cars[i].in_service = False
            cars[i].rides += 1
            cars[i].time = 0
        if cars[i].rides == 5 and cars[i].in_queue is False:
            push(i)
            cars[i].in_queue = True
        if cars[i].in_service is False:
            cars_in_service += 1
        i += 1
        lock.release()
    if cars_in_service == c and is_done >= 1:
        cars_done = 1
lock.acquire()
is_done += 1
lock.release()


def gas_station_thread(_gas_station):
global is_done
gas_station = _gas_station

truck = False
cars_filled = 0

v = gas_station.m_visitors
c = gas_station.n_cars
p = gas_station.k_pumps
t = gas_station.t_time
id = gas_station.thread_num

gas_done = 0
pumps_in_service = 0

j = 0
while gas_done == 0:
    while j < p:
        lock.acquire()
        if pumps[j].in_use is True:
            pumps[j].time += 1
        if pumps[j].time == 3:
            lock.acquire()
            cars[j].in_service = 0
            cars[j].rides = 0
            cars[j].time = 0
            cars[j].in_queue = False
            lock.release()
            pumps[j].time = 0
            pumps[j].in_use = False
            cars_filled += 1
            pumps_in_service -= 1
        if truck is True and pumps[j].in_use is False:
            truck = False
            print('Fuel Truck is currently filling up the gas station.')
        elif pumps[j].in_use is True and pump_line.size > 0:
            pumps_in_service += 1
            pumps[j].in_use = True
            pumps[j].car_num.pop()
            print('Car %d, pump %d' % (pumps[j].car_num + 1, i + 1))
            pumps[j].time = 0
        j += 1
        lock.release()

        if cars_filled > 3:
            print('The Fuel Truck is on its way')
            truck = True
            cars_filled = 0
        if pumps_in_service == 0 and is_done == 2:
            gas_done = True
        lock.acquire()
        is_done += 1
        lock.release()


def pop():
lock.acquire()
fr = pump_line.front
f = pump_line.pQueue[fr]
print("\n%d cars are waiting for pumps" % int(pump_line.size - 1))
if fr < (pump_line.MAXsize - 1):
    pump_line.front += 1
else:
    pump_line.front = 0
lock.release()

return f


def push(_c):
c =_c
lock.acquire()
b = pump_line.back
pump_line.pQueue[b] = c
print("\n%d cars are waiting for pumps" % int(pump_line.size + 1))
if b < (pump_line.MAXsize - 1):
    pump_line.back += 1
else:
    pump_line.back = 0
lock.release()


def isEmpty():
lock.acquire()
if (pump_line.front == pump_line.back):
    boolean = True
else:
    boolean = False
lock.release()

return boolean

if __name__ == "__main__":
arguments = Arguments(0, 0, 0, 0, 0, False)
main = Arguments(0, 0, 0, 0, 0, False)
thread = []
round_number = 0
io_control = 0
input_file = []
number_of_threads = 3
print("Enter the name of the text file to use as input:")
while io_control == 0:
    try:
        filename = input()
        input_file = open(filename)
        io_control = 1
    except IOError:
        print("Specified file does not exist, enter a different text file:")

# parse file into lines, separating by endlines
file_lines = []
num_lines = 0
for line in input_file:
    line = line.replace(",", " ")
    line = line.split()
    num_lines += 1
    if line:
        line = [int(i) for i in line]
        file_lines.append(line)

while main.done is False and round_number < num_lines:
    main.m_visitors = int(file_lines[round_number][0])
    main.n_cars = int(file_lines[round_number][1])
    main.k_pumps = int(file_lines[round_number][2])
    main.t_time = int(file_lines[round_number][3])

    print("\nRound Number: %d" % (round_number + 1))

    if main.n_cars == 0:
        print('No data to read in this round, press enter to continue:')
        input()

    print("Number of Visitors: %d" % main.m_visitors)
    print("Number of Cars: %d" % main.n_cars)
    print("Number of Pumps: %d" % main.k_pumps)
    print("Units of Time: %d" % main.t_time)

    M = main.m_visitors
    N = main.n_cars
    K = main.k_pumps
    T = main.t_time

    thread_info = []
    cars = []
    pumps = []
    for i in range(0, 3):
        temp = Arguments(M, N, K, T, i, False)
        thread_info.append(temp)

    for i in range(0, N):
        temp = Car(0, 0, 0, False, 0, False)
        cars.append(temp)

    for i in range(0, K):
        temp = Pump(0, False, 0, 0)
        pumps.append(temp)

    pump_line = PumpQueue(0, 0, 0, 0, N)

    visitorThread = Thread(target=visitor_thread, args=(thread_info[0],))
    thread.append(visitorThread)

    carsThread = Thread(target=car_thread, args=(thread_info[1],))
    thread.append(carsThread)

    gasThread = Thread(target=gas_station_thread, args=(thread_info[2],))
    thread.append(gasThread)

    visitorThread.start()
    carsThread.start()
    gasThread.start()

    visitorThread.join()
    carsThread.join()
    gasThread.join()

    round_number += 1

My output:

Round Number: 1 Number of Visitors: 35 Number of Cars: 6 Number of Pumps: 5 Units of Time: 2

Visitor 1 is currently in car 1

34 customers waiting for a ride.

Visitor 2 is currently in car 2

33 customers waiting for a ride.

Visitor 3 is currently in car 3

32 customers waiting for a ride.

Visitor 4 is currently in car 4

31 customers waiting for a ride.

Visitor 5 is currently in car 5

30 customers waiting for a ride.

Visitor 6 is currently in car 6

29 customers waiting for a ride.

Answer 1

I think there's an index problem here:

 if cars[j].in_service is False and cars[i].rides < 5:

should be

if cars[j].in_service is False and cars[j].rides < 5:

Index for cars is j not i