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"""
Bank renege example
Covers:
- Resources: Resource
- Condition events
Scenario:
A counter with a random service time and customers who renege. Based on the
program bank08.py from TheBank tutorial of SimPy 2. (KGM)
"""
import random
import simpy
RANDOM_SEED = 42
NEW_CUSTOMERS = 5 # Total number of customers
INTERVAL_CUSTOMERS = 10.0 # Generate new customers roughly every x seconds
MIN_PATIENCE = 1 # Min. customer patience
MAX_PATIENCE = 3 # Max. customer patience
def source(env, number, interval, counter):
"""Source generates customers randomly"""
for i in range(number):
c = customer(env, 'Customer%02d' % i, counter, time_in_bank=12.0)
env.process(c)
t = random.expovariate(1.0 / interval)
yield env.timeout(t)
def customer(env, name, counter, time_in_bank):
"""Customer arrives, is served and leaves."""
arrive = env.now
print('%7.4f %s: Here I am' % (arrive, name))
with counter.request() as req:
patience = random.uniform(MIN_PATIENCE, MAX_PATIENCE)
# Wait for the counter or abort at the end of our tether
results = yield req | env.timeout(patience)
wait = env.now - arrive
if req in results:
# We got to the counter
print('%7.4f %s: Waited %6.3f' % (env.now, name, wait))
tib = random.expovariate(1.0 / time_in_bank)
yield env.timeout(tib)
print('%7.4f %s: Finished' % (env.now, name))
else:
# We reneged
print('%7.4f %s: RENEGED after %6.3f' % (env.now, name, wait))
# Setup and start the simulation
print('Bank renege')
random.seed(RANDOM_SEED)
env = simpy.Environment()
# Start processes and run
counter = simpy.Resource(env, capacity=1)
env.process(source(env, NEW_CUSTOMERS, INTERVAL_CUSTOMERS, counter))
env.run()
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