update from Atlas

Author: ramalho

.gitignore

@@ -3,6 +3,7 @@ concurrency/charfinder/charfinder_index.pickle
 18-asyncio/charfinder/charfinder_index.pickle
 metaprog/oscon-schedule/data/schedule?_db
 concurrency/wikipedia/fixture/docroot/
+17-futures/countries/flags/
 
 # Byte-compiled / optimized / DLL files
 __pycache__/

16-coroutine/taxi_sim.py

@@ -0,0 +1,203 @@
+
+"""
+Taxi simulator
+==============
+
+Driving a taxi from the console::
+
+    >>> from taxi_sim import taxi_process
+    >>> taxi = taxi_process(ident=13, trips=2, start_time=0)
+    >>> next(taxi)
+    Event(time=0, proc=13, action='leave garage')
+    >>> taxi.send(_.time + 7)
+    Event(time=7, proc=13, action='pick up passenger')
+    >>> taxi.send(_.time + 23)
+    Event(time=30, proc=13, action='drop off passenger')
+    >>> taxi.send(_.time + 5)
+    Event(time=35, proc=13, action='pick up passenger')
+    >>> taxi.send(_.time + 48)
+    Event(time=83, proc=13, action='drop off passenger')
+    >>> taxi.send(_.time + 1)
+    Event(time=84, proc=13, action='going home')
+    >>> taxi.send(_.time + 10)
+    Traceback (most recent call last):
+      File "<stdin>", line 1, in <module>
+    StopIteration
+
+Sample run with two cars, random seed 10. This is a valid doctest::
+
+    >>> main(num_taxis=2, seed=10)
+    taxi: 0  Event(time=0, proc=0, action='leave garage')
+    taxi: 0  Event(time=5, proc=0, action='pick up passenger')
+    taxi: 1     Event(time=5, proc=1, action='leave garage')
+    taxi: 1     Event(time=10, proc=1, action='pick up passenger')
+    taxi: 1     Event(time=15, proc=1, action='drop off passenger')
+    taxi: 0  Event(time=17, proc=0, action='drop off passenger')
+    taxi: 1     Event(time=24, proc=1, action='pick up passenger')
+    taxi: 0  Event(time=26, proc=0, action='pick up passenger')
+    taxi: 0  Event(time=30, proc=0, action='drop off passenger')
+    taxi: 0  Event(time=34, proc=0, action='going home')
+    taxi: 1     Event(time=46, proc=1, action='drop off passenger')
+    taxi: 1     Event(time=48, proc=1, action='pick up passenger')
+    taxi: 1     Event(time=110, proc=1, action='drop off passenger')
+    taxi: 1     Event(time=139, proc=1, action='pick up passenger')
+    taxi: 1     Event(time=140, proc=1, action='drop off passenger')
+    taxi: 1     Event(time=150, proc=1, action='going home')
+    *** end of events ***
+
+See longer sample run at the end of this module.
+
+"""
+
+import random
+import collections
+import queue
+import argparse
+import time
+
+DEFAULT_NUMBER_OF_TAXIS = 3
+DEFAULT_END_TIME = 180
+SEARCH_DURATION = 5
+TRIP_DURATION = 20
+DEPARTURE_INTERVAL = 5
+
+Event = collections.namedtuple('Event', 'time proc action')
+
+
+# BEGIN TAXI_PROCESS
+def taxi_process(ident, trips, start_time=0):  # <1>
+    """Yield to simulator issuing event at each state change"""
+    time = yield Event(start_time, ident, 'leave garage')  # <2>
+    for i in range(trips):  # <3>
+        time = yield Event(time, ident, 'pick up passenger')  # <4>
+        time = yield Event(time, ident, 'drop off passenger')  # <5>
+
+    yield Event(time, ident, 'going home')  # <6>
+    # end of taxi process # <7>
+# END TAXI_PROCESS
+
+
+# BEGIN TAXI_SIMULATOR
+class Simulator:
+
+    def __init__(self, procs_map):
+        self.events = queue.PriorityQueue()
+        self.procs = dict(procs_map)
+
+    def run(self, end_time):  # <1>
+        """Schedule and display events until time is up"""
+        # schedule the first event for each cab
+        for _, proc in sorted(self.procs.items()):  # <2>
+            first_event = next(proc)  # <3>
+            self.events.put(first_event)  # <4>
+
+        # main loop of the simulation
+        sim_time = 0  # <5>
+        while sim_time < end_time:  # <6>
+            if self.events.empty():  # <7>
+                print('*** end of events ***')
+                break
+
+            current_event = self.events.get()  # <8>
+            sim_time, proc_id, previous_action = current_event  # <9>
+            print('taxi:', proc_id, proc_id * '   ', current_event)  # <10>
+            active_proc = self.procs[proc_id]  # <11>
+            next_time = sim_time + compute_duration(previous_action)  # <12>
+            try:
+                next_event = active_proc.send(next_time)  # <13>
+            except StopIteration:
+                del self.procs[proc_id]  # <14>
+            else:
+                self.events.put(next_event)  # <15>
+        else:  # <16>
+            msg = '*** end of simulation time: {} events pending ***'
+            print(msg.format(self.events.qsize()))
+# END TAXI_SIMULATOR
+
+
+def compute_duration(previous_action):
+    """Compute action duration using exponential distribution"""
+    if previous_action in ['leave garage', 'drop off passenger']:
+        # new state is prowling
+        interval = SEARCH_DURATION
+    elif previous_action == 'pick up passenger':
+        # new state is trip
+        interval = TRIP_DURATION
+    elif previous_action == 'going home':
+        interval = 1
+    else:
+        raise ValueError('Unknown previous_action: %s' % previous_action)
+    return int(random.expovariate(1/interval)) + 1
+
+
+def main(end_time=DEFAULT_END_TIME, num_taxis=DEFAULT_NUMBER_OF_TAXIS,
+         seed=None):
+    """Initialize random generator, build procs and run simulation"""
+    if seed is not None:
+        random.seed(seed)  # get reproducible results
+
+    taxis = {i: taxi_process(i, (i+1)*2, i*DEPARTURE_INTERVAL)
+             for i in range(num_taxis)}
+    sim = Simulator(taxis)
+    sim.run(end_time)
+
+
+if __name__ == '__main__':
+
+    parser = argparse.ArgumentParser(
+                        description='Taxi fleet simulator.')
+    parser.add_argument('-e', '--end-time', type=int,
+                        default=DEFAULT_END_TIME,
+                        help='simulation end time; default = %s'
+                        % DEFAULT_END_TIME)
+    parser.add_argument('-t', '--taxis', type=int,
+                        default=DEFAULT_NUMBER_OF_TAXIS,
+                        help='number of taxis running; default = %s'
+                        % DEFAULT_NUMBER_OF_TAXIS)
+    parser.add_argument('-s', '--seed', type=int, default=None,
+                        help='random generator seed (for testing)')
+
+    args = parser.parse_args()
+    main(args.end_time, args.taxis, args.seed)
+
+
+"""
+
+Sample run from the command line, seed=3, maximum elapsed time=120::
+
+# BEGIN TAXI_SAMPLE_RUN
+$ python3 taxi_sim.py -s 3 -e 120
+taxi: 0  Event(time=0, proc=0, action='leave garage')
+taxi: 0  Event(time=2, proc=0, action='pick up passenger')
+taxi: 1     Event(time=5, proc=1, action='leave garage')
+taxi: 1     Event(time=8, proc=1, action='pick up passenger')
+taxi: 2        Event(time=10, proc=2, action='leave garage')
+taxi: 2        Event(time=15, proc=2, action='pick up passenger')
+taxi: 2        Event(time=17, proc=2, action='drop off passenger')
+taxi: 0  Event(time=18, proc=0, action='drop off passenger')
+taxi: 2        Event(time=18, proc=2, action='pick up passenger')
+taxi: 2        Event(time=25, proc=2, action='drop off passenger')
+taxi: 1     Event(time=27, proc=1, action='drop off passenger')
+taxi: 2        Event(time=27, proc=2, action='pick up passenger')
+taxi: 0  Event(time=28, proc=0, action='pick up passenger')
+taxi: 2        Event(time=40, proc=2, action='drop off passenger')
+taxi: 2        Event(time=44, proc=2, action='pick up passenger')
+taxi: 1     Event(time=55, proc=1, action='pick up passenger')
+taxi: 1     Event(time=59, proc=1, action='drop off passenger')
+taxi: 0  Event(time=65, proc=0, action='drop off passenger')
+taxi: 1     Event(time=65, proc=1, action='pick up passenger')
+taxi: 2        Event(time=65, proc=2, action='drop off passenger')
+taxi: 2        Event(time=72, proc=2, action='pick up passenger')
+taxi: 0  Event(time=76, proc=0, action='going home')
+taxi: 1     Event(time=80, proc=1, action='drop off passenger')
+taxi: 1     Event(time=88, proc=1, action='pick up passenger')
+taxi: 2        Event(time=95, proc=2, action='drop off passenger')
+taxi: 2        Event(time=97, proc=2, action='pick up passenger')
+taxi: 2        Event(time=98, proc=2, action='drop off passenger')
+taxi: 1     Event(time=106, proc=1, action='drop off passenger')
+taxi: 2        Event(time=109, proc=2, action='going home')
+taxi: 1     Event(time=110, proc=1, action='going home')
+*** end of events ***
+# END TAXI_SAMPLE_RUN
+
+"""