@ -1,22 +1,63 @@
"""
This is an example of a simplified city , where there are Passengers and Drivers that can take those passengers
from their location to their desired location .
An example scenario could play like the following :
- Drivers start in the ` wandering ` state , where they wander around the city until they have been assigned a journey
- Passenger ( 1 ) tells every driver that it wants to request a Journey .
- Each driver receives the request .
If Driver ( 2 ) is interested in providing the Journey , it asks Passenger ( 1 ) to confirm that it accepts Driver ( 2 ) ' s request
- When Passenger ( 1 ) accepts the request , two things happen :
- Passenger ( 1 ) changes its state to ` driving_home `
- Driver ( 2 ) starts moving towards the origin of the Journey
- Once Driver ( 2 ) reaches the origin , it starts moving itself and Passenger ( 1 ) to the destination of the Journey
- When Driver ( 2 ) reaches the destination ( carrying Passenger ( 1 ) along ) :
- Driver ( 2 ) starts wondering again
- Passenger ( 1 ) dies , and is removed from the simulation
- If there are no more passengers available in the simulation , Drivers die
"""
from __future__ import annotations
from soil import *
from soil import events
from mesa . space import MultiGrid
from enum import Enum
# More complex scenarios may use more than one type of message between objects.
# A common pattern is to use `enum.Enum` to represent state changes in a request.
@dataclass
class Journey :
"""
This represents a request for a journey . Passengers and drivers exchange this object .
A journey may have a driver assigned or not . If the driver has not been assigned , this
object is considered a " request for a journey " .
"""
origin : ( int , int )
destination : ( int , int )
tip : float
passenger : Passenger = None
passenger : Passenger
driver : Driver = None
class City ( EventedEnvironment ) :
def __init__ ( self , * args , n_cars = 1 , height = 100 , width = 100 , n_passengers = 10 , agents = None , * * kwargs ) :
"""
An environment with a grid where drivers and passengers will be placed .
The number of drivers and riders is configurable through its parameters :
: param str n_cars : The total number of drivers to add
: param str n_passengers : The number of passengers in the simulation
: param list agents : Specific agents to use in the simulation . It overrides the ` n_passengers `
and ` n_cars ` params .
: param int height : Height of the internal grid
: param int width : Width of the internal grid
"""
def __init__ ( self , * args , n_cars = 1 , n_passengers = 10 ,
height = 100 , width = 100 , agents = None ,
model_reporters = None ,
* * kwargs ) :
self . grid = MultiGrid ( width = width , height = height , torus = False )
if agents is None :
agents = [ ]
@ -24,53 +65,73 @@ class City(EventedEnvironment):
agents . append ( { ' agent_class ' : Driver } )
for i in range ( n_passengers ) :
agents . append ( { ' agent_class ' : Passenger } )
super ( ) . __init__ ( * args , agents = agents , * * kwargs )
model_reporters = model_reporters or { ' earnings ' : ' total_earnings ' , ' n_passengers ' : ' number_passengers ' }
print ( ' REPORTERS ' , model_reporters )
super ( ) . __init__ ( * args , agents = agents , model_reporters = model_reporters , * * kwargs )
for agent in self . agents :
self . grid . place_agent ( agent , ( 0 , 0 ) )
self . grid . move_to_empty ( agent )
@property
def total_earnings ( self ) :
return sum ( d . earnings for d in self . agents ( agent_class = Driver ) )
@property
def number_passengers ( self ) :
return self . count_agents ( agent_class = Passenger )
class Driver ( Evented , FSM ) :
pos = None
journey = None
earnings = 0
def on_receive ( self , msg , sender ) :
''' This is not a state. It will run (and block) every time check_messages is invoked '''
if self . journey is None and isinstance ( msg , Journey ) and msg . driver is None :
msg . driver = self
self . journey = msg
def check_passengers ( self ) :
''' If there are no more passengers, stop forever '''
c = self . count_agents ( agent_class = Passenger )
self . info ( f " Passengers left { c } " )
if not c :
self . die ( )
@default_state
@state
def wandering ( self ) :
''' Move around the city until a journey is accepted '''
target = None
self . check_passengers ( )
self . journey = None
while self . journey is None :
while self . journey is None : # No potential journeys detected (see on_receive)
if target is None or not self . move_towards ( target ) :
target = self . random . choice ( self . model . grid . get_neighborhood ( self . pos , moore = False ) )
self . check_passengers ( )
self . check_messages ( ) # This will call on_receive behind the scenes
yield Delta ( 30 )
self . check_messages ( ) # This will call on_receive behind the scenes, and the agent's status will be updated
yield Delta ( 30 ) # Wait at least 30 seconds before checking again
try :
# Re-send the journey to the passenger, to confirm that we have been selected
self . journey = yield self . journey . passenger . ask ( self . journey , timeout = 60 )
except events . TimedOut :
# No journey has been accepted. Try again
self . journey = None
return
return self . driving
def check_passengers ( self ) :
c = self . count_agents ( agent_class = Passenger )
self . info ( f " Passengers left { c } " )
if not c :
self . die ( )
return self . driving
@state
def driving ( self ) :
#Approaching
''' The journey has been accepted. Pick them up and take them to their destination '''
while self . move_towards ( self . journey . origin ) :
yield
while self . move_towards ( self . journey . destination , with_passenger = True ) :
yield
self . earnings + = self . journey . tip
self . check_passengers ( )
return self . wandering
@ -97,6 +158,14 @@ class Driver(Evented, FSM):
class Passenger ( Evented , FSM ) :
pos = None
def on_receive ( self , msg , sender ) :
''' This is not a state. It will be run synchronously every time `check_messages` is run '''
if isinstance ( msg , Journey ) :
self . journey = msg
return msg
@default_state
@state
def asking ( self ) :
@ -121,11 +190,6 @@ class Passenger(Evented, FSM):
self . check_messages ( )
return self . driving_home
def on_receive ( self , msg , sender ) :
if isinstance ( msg , Journey ) :
self . journey = msg
return msg
@state
def driving_home ( self ) :
while self . pos [ 0 ] != self . journey . destination [ 0 ] or self . pos [ 1 ] != self . journey . destination [ 1 ] :
@ -134,7 +198,7 @@ class Passenger(Evented, FSM):
self . die ( )
simulation = Simulation ( = City , model_params = { ' n_passengers ' : 2 } )
simulation = Simulation ( name= ' RideHailing ' , model_class= City , model_params = { ' n_passengers ' : 2 } )
if __name__ == " __main__ " :
with easy ( simulation ) as s :
J. Fernando Sánchez
2 years ago