simulation_classes.train

  1"""
  2This module defines the Train class, which simulates the loading and unloading of cargo at a terminal.
  3The train processes cargo in batches, either importing or exporting based on the flags provided.
  4"""
  5
  6from simulation_classes.port import Container
  7
  8class Train(object):
  9    """Train class to simulate the loading and unloading of cargo at a terminal.
 10        Args:
 11            env (simpy.Environment): Simulation environment.
 12            train_id (str): Unique identifier for the train.
 13            terminal_id (str): Unique identifier for the terminal.
 14            car_amount (int): Number of cars in the train.
 15            cargo_transfer_rate (float): Rate at which cargo is transferred (e.g., pounds per hour).
 16            racks (simpy.Resource): Resource representing the unloading racks.
 17            cargo_yard (simpy.Container): Container representing the cargo yard.
 18            train_events (dict): Dictionary to log events related to the train.
 19            transfer_amount (float): Total amount of cargo to be transferred per car.
 20            import_bool (bool): Flag indicating if the train is importing cargo.
 21            export_bool (bool): Flag indicating if the train is exporting cargo.
 22            cargo_type (str): Type of cargo being handled ("Container" or "Bulk").
 23        """
 24    def __init__(self, env, train_id, terminal_id, car_amount, cargo_transfer_rate, racks, cargo_yard, train_events, transfer_amount, import_bool, export_bool, cargo_type):
 25        self.env = env
 26        self.train_id = train_id
 27        self.terminal_id = terminal_id
 28        self.car_amount = car_amount  
 29        self.cargo_transfer_rate = cargo_transfer_rate 
 30        self.racks = racks  # simpy.Resource object for unloading
 31        self.cargo_yard = cargo_yard
 32        self.train_events = train_events
 33        self.transfer_amount_per_car = transfer_amount / car_amount
 34        self.import_bool = import_bool
 35        self.export_bool = export_bool
 36        self.cargo_type = cargo_type
 37        self.env.process(self.process())
 38
 39    def process(self):
 40        """
 41        Process to handle the train's loading and unloading operations.
 42        This method initializes the train's event log, waits for the train to arrive,
 43        and then either imports or exports cargo based on the flags provided.
 44        It also logs the time taken for each operation and the start/end times of each car.
 45        """
 46        # Initialize train event log
 47        self.train_events[self.train_id] = {}
 48        self.train_events[self.train_id]["Batch size"] = self.racks.capacity
 49        self.train_events[self.train_id]["Cargo type"] = self.cargo_type
 50        self.train_events[self.train_id]["Cargo transfer rate"] = self.cargo_transfer_rate
 51        self.train_events[self.train_id]["Transfer amount per car"] = self.transfer_amount_per_car
 52        self.train_events[self.train_id]["Import/Export"] = "Import" if self.import_bool else "Export"
 53        self.train_events[self.train_id]["Train ID"] = self.train_id
 54        self.train_events[self.train_id]["Terminal ID"] = self.terminal_id
 55        self.train_events[self.train_id]["Car amount"] = self.car_amount
 56        self.train_events[self.train_id]["Car start/end times"] = []
 57        self.train_events[self.train_id]["Time to get racks"] = []
 58        self.train_events[self.train_id]["Train Arrival"] = self.env.now    
 59
 60        if self.import_bool:  # Import Process
 61            yield self.env.process(self.import_cargo(self.car_amount))
 62        if self.export_bool:  # Export Process
 63            yield self.env.process(self.export_cargo(self.car_amount))
 64
 65        self.train_events[self.train_id]["Train Departure"] = self.env.now
 66        self.train_events[self.train_id]["Train Duration"] = self.train_events[self.train_id]["Train Departure"] - self.train_events[self.train_id]["Train Arrival"]
 67
 68    def import_cargo(self, empty_cars):
 69        """
 70        Import cargo into the train's cars.
 71        This method processes the loading of cargo into the train's cars in batches.
 72        Args:
 73            empty_cars (int): Number of empty cars to be loaded with cargo.
 74        Yields:
 75            simpy.Timeout: Waits for all cars in the batch to be loaded before proceeding.
 76        Returns:
 77            None
 78        """
 79        cars_remaining = empty_cars
 80        while cars_remaining > 0:
 81            batch_size = min(cars_remaining, self.racks.capacity)
 82            tasks = [self.env.process(self.load_car()) for _ in range(batch_size)]
 83            yield self.env.all_of(tasks)  # Wait for all cars in the batch to be loaded
 84            cars_remaining -= batch_size
 85
 86    def export_cargo(self, full_cars):
 87        """
 88        Export cargo from the train's cars.
 89        This method processes the unloading of cargo from the train's cars in batches.
 90        Args:
 91            full_cars (int): Number of full cars to be unloaded.
 92        Yields:
 93            simpy.Timeout: Waits for all cars in the batch to be unloaded before proceeding.
 94        Returns:
 95            None
 96        """
 97        cars_remaining = full_cars
 98        while cars_remaining > 0:
 99            batch_size = min(cars_remaining, self.racks.capacity)
100            tasks = [self.env.process(self.unload_car()) for _ in range(batch_size)]
101            yield self.env.all_of(tasks)  # Wait for all cars in the batch to be unloaded
102            cars_remaining -= batch_size                                                                                              
103
104    def load_car(self):
105        """
106        Load cargo into a single car of the train.
107        This method handles the loading of cargo into a car, including waiting for the racks
108        and calculating the time taken for loading.
109        Yields:
110            simpy.Timeout: Waits for the loading process to complete.
111        Returns:
112            None
113        """
114        car_start_time = self.env.now
115        with self.racks.request() as req:
116            yield req
117            self.train_events[self.train_id]["Time to get racks"].append(self.env.now - car_start_time)
118            load_time = self.transfer_amount_per_car / self.cargo_transfer_rate # ex: (50 lbs / car) / (20 lbs/hr) = 2.5 hr / car
119            yield self.env.timeout(load_time)
120            if self.cargo_type == "Container":
121                num_containers =  int(self.transfer_amount_per_car)
122                for i in range(num_containers):
123                    yield self.cargo_yard.get()
124            else:
125                yield self.cargo_yard.get(self.transfer_amount_per_car)
126        car_end_time = self.env.now
127        self.train_events[self.train_id]["Car start/end times"].append((car_start_time, car_end_time))
128            
129
130    def unload_car(self):
131        """
132        Unload cargo from a single car of the train.
133        This method handles the unloading of cargo from a car, including waiting for the racks
134        and calculating the time taken for unloading.
135        Yields:
136            simpy.Timeout: Waits for the unloading process to complete.
137        Returns:
138            None
139        """
140        car_start_time = self.env.now
141        with self.racks.request() as req:
142            yield req
143            self.train_events[self.train_id]["Time to get racks"].append(self.env.now - car_start_time)
144            unload_time = self.transfer_amount_per_car / self.cargo_transfer_rate # ex: (50 lbs / car) / (20 lbs/hr) = 2.5 hr / car
145            yield self.env.timeout(unload_time)
146            if self.cargo_type == "Container":
147                num_containers =  int(self.transfer_amount_per_car)
148                for i in range(num_containers):
149                    ctr = Container(id=f"{self.train_id}_unload_{i}", width=100000)
150                    yield self.cargo_yard.put(ctr)
151            else:
152                self.cargo_yard.put(self.transfer_amount_per_car)
153        car_end_time = self.env.now
154        self.train_events[self.train_id]["Car start/end times"].append((car_start_time, car_end_time))
155
156                                  
157            
158            
159            
160             
161             
162               
163            
164             
165             
166            
167            
168