async.py

import threading

import tensorflow as tf
import gym


class GlobalCounter:
  def __init__(self):
    n = 0


def main():

    ACTION_SPACE = 2

    NUM_AGENTS = 8

    N_STEPS = 50000

    with tf.device("/cpu:0"):

        global_counter = GlobalCounter()

        global_history = []

        global_ACNet = ActorCriticNet(ACTION_SPACE)

        global_ACNet.build(input_shape=(None, 4))

        agents = []

        for agent_id in range(NUM_AGENTS):

            agent = A3CAgent(agent_id=f"agent_{agent_id}",
                             env=gym.envs.make("CartPole-v1"),
                             global_counter=global_counter,
                             action_space=ACTION_SPACE,
                             global_ACNet=global_ACNet,
                             gamma=0.99,
                             global_history=global_history,
                             global_steps_fin=N_STEPS)

            agents.append(agent)

    coord = tf.train.Coordinator()
    agent_threads = []
    for agent in agents:
        target_func = (lambda: agent.play(coord))
        thread = threading.Thread(target=target_func)
        thread.start()
        agent_threads.append(thread)

    coord.join(agent_threads, stop_grace_period_secs=300)