# 14_MM1.py

import random

import simpy

# RANDOM_SEED = 42 # Include to achieve repeatable results

NUM_MACHINES = 1 # number of washing machines. MM1

WASHING_TIME = 5 # The service time of a machine

ARRIVAL_TIME = 7 # time between arrivals,

# 1 vehicle comes every 7 minutes

SIMULATION_TIME = 20 # simulation time in minutes

class WashingMachine:

'''

A washing machine has a limited number of machines. In this example is one.

The vehicles request resources of the available machine using the request()

method. Once the resource is assigned, washing starts and should be

expected to finish in the WASHING_TIME defined.

'''

def __init__(self, env, num_machines, washing_time):

self.env = env

# Create a Resource with num_machines machines

self.machines = simpy.Resource(env,

capacity=num_machines)

self.washing_time = washing_time

def wash(self, vehicle):

'''Washing starts with a random time with probability distribution

exponential with rate 1 / TIEMPO_LAVADO'''

yield self.env.timeout(round(

random.expovariate(1 / self.washing_time) + 0.5))

def vehicle(env, vehicle_id, washing_machine):

'''During washing, a vehicle arrives to machine and asks use. Once you

start washing, waits until it finishes and then frees the machine.'''

print('{0} arrives to machine in {1:.2f}.'.format(vehicle_id, env.now))

with washing_machine.machines.request() as request:

yield request

print('{0} enters to machine in {1:.2f}.'

.format(vehicle_id, env.now))

yield env.process(washing_machine.wash(vehicle_id))

print('{0} goes out from machine in {1:.2f}.'

.format(vehicle_id, env.now))

def sim_configuration(env, num_machines,

washing_time,

arrival_time):

''' In this routine: washing machines are created, an initial number of

vehicles (2) and then vehicles arrive at a rate of 1 / arrival_time'''

# Create a washing machine

machine = WashingMachine(env, num_machines, washing_time)

# 2 vehicles are created and put in to the queue

print('In the queue there are already 2 vehicles')

for i in range(2):

env.process(vehicle(env, 'Vehicle {0}'.format(i), machine))

# While the machine runs vehicles arrive at a rate of 1 / arrival_time

while True:

yield env.timeout(round(random.expovariate(1 / arrival_time)))

i += 1

env.process(vehicle(env, 'Vehicle {0}'.format(i), machine))

# Simulation configuration

# random.seed(RANDOM_SEED)

# Simulation environment creation

env = simpy.Environment()

env.process(sim_configuration(env, NUM_MACHINES,

WASHING_TIME,

ARRIVAL_TIME))

# Runs simulation until SIMULATION_TIME minutes

env.run(until=SIMULATION_TIME)