fixed bug in taxi_sim.py

Author: ramalho

control/simulation/taxi_sim.py

@@ -3,62 +3,108 @@
 import collections
 import queue
 
-FIND_CUSTOMER_INTERVAL = 4
+FIND_PASSENGER_INTERVAL = 4
 TRIP_DURATION = 10
 
 Event = collections.namedtuple('Event', 'time actor description')
 
+
 def compute_delay(interval):
     return int(random.expovariate(1/interval)) + 1
 
 
-def taxi_process(sim, ident):
-    trips = 3
+def taxi_process(ident, trips):
+    trip_ends = 0
     for i in range(trips):
-        prowling_time = compute_delay(FIND_CUSTOMER_INTERVAL)
-        yield Event(sim.time + prowling_time, ident, 'customer picked up')
+        prowling_ends = trip_ends + compute_delay(FIND_PASSENGER_INTERVAL)
+        yield Event(prowling_ends, ident, 'passenger picked up')
 
-        trip_time = compute_delay(TRIP_DURATION)
-        yield Event(sim.time + trip_time, ident, 'customer dropped off')
+        trip_ends = prowling_ends + compute_delay(TRIP_DURATION)
+        yield Event(trip_ends, ident, 'passenger dropped off')
 
 
 class Simulator:
 
-    def __init__(self):
+    def __init__(self, actors):
         self.events = queue.PriorityQueue()
+        self.actors = list(actors)
         self.time = 0
 
+    def schedule_events(self, end_time):
+        for index, actor in enumerate(list(self.actors)):
+            try:
+                future_event = next(actor)
+            except StopIteration:
+                self.actors.remove(actor)  # remove exhausted actor
+            else:
+                self.events.put(future_event)
+
     def run(self, end_time):
-        #import pdb; pdb.set_trace()
-        taxis = [taxi_process(self, i) for i in range(3)]
         while self.time < end_time:
-            for index, taxi in enumerate(taxis):
-                try:
-                    future_event = next(taxi)
-                except StopIteration:
-                    del taxis[index]  # remove taxi not in service
-                else:
-                    self.events.put(future_event)
+            self.schedule_events(end_time)
             if self.events.empty():
                 print('*** end of events ***')
                 break
             event = self.events.get()
             self.time = event.time
-            print('taxi:', event.actor, event)
+            print('taxi:', event.actor, event.actor * '   ', event)
         else:
-            print('*** end of simulation time ***')
+            msg = '*** end of simulation time: {} events pending ***'
+            print(msg.format(self.events.qsize()))
+
+
+def extract_seed(args):
+    """Set random seed if given in command line"""
+    for index, arg in enumerate(list(args)):
+        if arg.startswith('seed='):  # for testing...
+            seed = int(arg.split('=')[1])
+            random.seed(seed)  # get reproducible results
+            del args[index]
+            return
 
 
 def main(args):
-    if 'debug' in args:  # for testing...
-        random.seed(0)  # get reproducible results
-        args.remove('debug')
+    extract_seed(args)
     if args:
         end_time = int(args[0])
     else:
-        end_time = 10
-    sim = Simulator()
+        end_time = 100
+    taxis = [taxi_process(i, (i+1)*2) for i in range(3)]
+    sim = Simulator(taxis)
     sim.run(end_time)
 
 if __name__ == '__main__':
     main(sys.argv[1:])
+
+
+"""
+Sample run:
+
+$ python3 taxi_sim.py seed=5 110
+taxi: 0  Event(time=4, actor=0, description='passenger picked up')
+taxi: 1     Event(time=6, actor=1, description='passenger picked up')
+taxi: 2        Event(time=7, actor=2, description='passenger picked up')
+taxi: 1     Event(time=20, actor=1, description='passenger dropped off')
+taxi: 1     Event(time=23, actor=1, description='passenger picked up')
+taxi: 0  Event(time=33, actor=0, description='passenger dropped off')
+taxi: 2        Event(time=33, actor=2, description='passenger dropped off')
+taxi: 0  Event(time=34, actor=0, description='passenger picked up')
+taxi: 0  Event(time=45, actor=0, description='passenger dropped off')
+taxi: 2        Event(time=45, actor=2, description='passenger picked up')
+taxi: 1     Event(time=47, actor=1, description='passenger dropped off')
+taxi: 2        Event(time=47, actor=2, description='passenger dropped off')
+taxi: 2        Event(time=49, actor=2, description='passenger picked up')
+taxi: 1     Event(time=50, actor=1, description='passenger picked up')
+taxi: 1     Event(time=58, actor=1, description='passenger dropped off')
+taxi: 2        Event(time=58, actor=2, description='passenger dropped off')
+taxi: 1     Event(time=59, actor=1, description='passenger picked up')
+taxi: 2        Event(time=59, actor=2, description='passenger picked up')
+taxi: 1     Event(time=63, actor=1, description='passenger dropped off')
+taxi: 2        Event(time=84, actor=2, description='passenger dropped off')
+taxi: 2        Event(time=90, actor=2, description='passenger picked up')
+taxi: 2        Event(time=92, actor=2, description='passenger dropped off')
+taxi: 2        Event(time=99, actor=2, description='passenger picked up')
+taxi: 2        Event(time=101, actor=2, description='passenger dropped off')
+*** end of events ***
+
+"""