FAQ_Challenge.md

normalized_reward =cumulative_reward / (self.env._max_episode_steps +self.env.get_num_agents()
from flatland.envs.malfunction_generators import malfunction_from_params
from flatland.envs.rail_env import RailEnv
from flatland.envs.rail_generators import sparse_rail_generator
from flatland.envs.schedule_generators import sparse_schedule_generator
stochastic_data = {'malfunction_rate': 8000,  # Rate of malfunction occurence of single agent
                   'min_duration': 15,  # Minimal duration of malfunction
                   'max_duration': 50  # Max duration of malfunction
                   }

# Custom observation builder without predictor
observation_builder = YourObservationBuilder()

width = 16 * 7  # With of map
height = 9 * 7  # Height of map
nr_trains = 50  # Number of trains that have an assigned task in the env
cities_in_map = 20  # Number of cities where agents can start or end
seed = 14  # Random seed
grid_distribution_of_cities = False  # Type of city distribution, if False cities are randomly placed
max_rails_between_cities = 2  # Max number of tracks allowed between cities. This is number of entry point to a city
max_rail_in_cities = 6  # Max number of parallel tracks within a city, representing a realistic trainstation

rail_generator = sparse_rail_generator(max_num_cities=cities_in_map,
                                       seed=seed,
                                       grid_mode=grid_distribution_of_cities,
                                       max_rails_between_cities=max_rails_between_cities,
                                       max_rails_in_city=max_rail_in_cities,
                                       )
# Different agent types (trains) with different speeds.
speed_ration_map = {1.: 0.25,  # Fast passenger train
                    1. / 2.: 0.25,  # Fast freight train
                    1. / 3.: 0.25,  # Slow commuter train
                    1. / 4.: 0.25}  # Slow freight train

# We can now initiate the schedule generator with the given speed profiles

schedule_generator = sparse_schedule_generator(speed_ration_map)

# Construct the enviornment with the given observation, generataors, predictors, and stochastic data
env = RailEnv(width=width,
              height=height,
              rail_generator=rail_generator,
              schedule_generator=schedule_generator,
              number_of_agents=nr_trains,
              obs_builder_object=observation_builder,
              malfunction_generator_and_process_data=malfunction_from_params(stochastic_data),
              remove_agents_at_target=True)