示例#1
0
    def make_build_train(self):
        # Build act and train networks
        self.act, self.train, self.update_target, self.debug = deepq.build_train(
            make_obs_ph=self.make_obs_ph,
            q_func=self.q_func,
            num_actions=self.env.action_space.n,
            optimizer=tf.train.AdamOptimizer(learning_rate=self.lr),
            gamma=self.gamma,
            grad_norm_clipping=10,
            param_noise=self.param_noise
        )

        self.act_params = {
            'make_obs_ph': self.make_obs_ph,
            'q_func': self.q_func,
            'num_actions': self.env.action_space.n,
        }

        self.act = ActWrapper(self.act, self.act_params)

        return 'make_build_train() complete'
示例#2
0
def learn(env,
          q_func,
          lr=5e-4,
          max_timesteps=100000,
          buffer_size=50000,
          exploration_fraction=0.1,
          exploration_final_eps=0.02,
          train_freq=1,
          batch_size=32,
          print_freq=100,
          checkpoint_freq=10000,
          learning_starts=1000,
          gamma=1.0,
          target_network_update_freq=500,
          prioritized_replay=False,
          prioritized_replay_alpha=0.6,
          prioritized_replay_beta0=0.4,
          prioritized_replay_beta_iters=None,
          prioritized_replay_eps=1e-6,
          param_noise=False,
          callback=None):
    """Train a deepq model.

    Parameters
    -------
    env: gym.Env
        environment to train on
    q_func: (tf.Variable, int, str, bool) -> tf.Variable
        the model that takes the following inputs:
            observation_in: object
                the output of observation placeholder
            num_actions: int
                number of actions
            scope: str
            reuse: bool
                should be passed to outer variable scope
        and returns a tensor of shape (batch_size, num_actions) with values of every action.
    lr: float
        learning rate for adam optimizer
    max_timesteps: int
        number of env steps to optimizer for
    buffer_size: int
        size of the replay buffer
    exploration_fraction: float
        fraction of entire training period over which the exploration rate is annealed
    exploration_final_eps: float
        final value of random action probability
    train_freq: int
        update the model every `train_freq` steps.
        set to None to disable printing
    batch_size: int
        size of a batched sampled from replay buffer for training
    print_freq: int
        how often to print out training progress
        set to None to disable printing
    checkpoint_freq: int
        how often to save the model. This is so that the best version is restored
        at the end of the training. If you do not wish to restore the best version at
        the end of the training set this variable to None.
    learning_starts: int
        how many steps of the model to collect transitions for before learning starts
    gamma: float
        discount factor
    target_network_update_freq: int
        update the target network every `target_network_update_freq` steps.
    prioritized_replay: True
        if True prioritized replay buffer will be used.
    prioritized_replay_alpha: float
        alpha parameter for prioritized replay buffer
    prioritized_replay_beta0: float
        initial value of beta for prioritized replay buffer
    prioritized_replay_beta_iters: int
        number of iterations over which beta will be annealed from initial value
        to 1.0. If set to None equals to max_timesteps.
    prioritized_replay_eps: float
        epsilon to add to the TD errors when updating priorities.
    callback: (locals, globals) -> None
        function called at every steps with state of the algorithm.
        If callback returns true training stops.

    Returns
    -------
    act: ActWrapper
        Wrapper over act function. Adds ability to save it and load it.
        See header of baselines/deepq/categorical.py for details on the act function.
    """
    # Create all the functions necessary to train the model

    sess = tf.Session()
    sess.__enter__()

    # capture the shape outside the closure so that the env object is not serialized
    # by cloudpickle when serializing make_obs_ph
    observation_space_shape = env.observation_space.shape

    def make_obs_ph(name):
        return U.BatchInput(observation_space_shape, name=name)

    act, train, update_target, debug = deepq.build_train(
        make_obs_ph=make_obs_ph,
        q_func=q_func,
        num_actions=env.action_space.n,
        optimizer=tf.train.AdamOptimizer(learning_rate=lr),
        gamma=gamma,
        grad_norm_clipping=10,
        param_noise=param_noise)

    act_params = {
        'make_obs_ph': make_obs_ph,
        'q_func': q_func,
        'num_actions': env.action_space.n,
    }

    act = ActWrapper(act, act_params)

    # Create the replay buffer
    if prioritized_replay:
        replay_buffer = PrioritizedReplayBuffer(buffer_size,
                                                alpha=prioritized_replay_alpha)
        if prioritized_replay_beta_iters is None:
            prioritized_replay_beta_iters = max_timesteps
        beta_schedule = LinearSchedule(prioritized_replay_beta_iters,
                                       initial_p=prioritized_replay_beta0,
                                       final_p=1.0)
    else:
        replay_buffer = ReplayBuffer(buffer_size)
        beta_schedule = None
    # Create the schedule for exploration starting from 1.
    exploration = LinearSchedule(schedule_timesteps=int(exploration_fraction *
                                                        max_timesteps),
                                 initial_p=1.0,
                                 final_p=exploration_final_eps)

    # Initialize the parameters and copy them to the target network.
    U.initialize()
    update_target()

    episode_rewards = [0.0]
    saved_mean_reward = None
    obs = env.reset()
    reset = True
    with tempfile.TemporaryDirectory() as td:
        model_saved = False
        model_file = os.path.join(td, "model")
        for t in range(max_timesteps):
            if callback is not None:
                if callback(locals(), globals()):
                    break
            # Take action and update exploration to the newest value
            kwargs = {}
            if not param_noise:
                update_eps = exploration.value(t)
                update_param_noise_threshold = 0.
            else:
                update_eps = 0.
                # Compute the threshold such that the KL divergence between perturbed and non-perturbed
                # policy is comparable to eps-greedy exploration with eps = exploration.value(t).
                # See Appendix C.1 in Parameter Space Noise for Exploration, Plappert et al., 2017
                # for detailed explanation.
                update_param_noise_threshold = -np.log(1. - exploration.value(
                    t) + exploration.value(t) / float(env.action_space.n))
                kwargs['reset'] = reset
                kwargs[
                    'update_param_noise_threshold'] = update_param_noise_threshold
                kwargs['update_param_noise_scale'] = True
            action = act(np.array(obs)[None], update_eps=update_eps,
                         **kwargs)[0]
            env_action = action
            reset = False
            new_obs, rew, done, _ = env.step(env_action)
            # Store transition in the replay buffer.
            replay_buffer.add(obs, action, rew, new_obs, float(done))
            obs = new_obs

            episode_rewards[-1] += rew
            if done:
                obs = env.reset()
                episode_rewards.append(0.0)
                reset = True

            if t > learning_starts and t % train_freq == 0:
                # Minimize the error in Bellman's equation on a batch sampled from replay buffer.
                if prioritized_replay:
                    experience = replay_buffer.sample(
                        batch_size, beta=beta_schedule.value(t))
                    (obses_t, actions, rewards, obses_tp1, dones, weights,
                     batch_idxes) = experience
                else:
                    obses_t, actions, rewards, obses_tp1, dones = replay_buffer.sample(
                        batch_size)
                    weights, batch_idxes = np.ones_like(rewards), None
                td_errors = train(obses_t, actions, rewards, obses_tp1, dones,
                                  weights)
                if prioritized_replay:
                    new_priorities = np.abs(td_errors) + prioritized_replay_eps
                    replay_buffer.update_priorities(batch_idxes,
                                                    new_priorities)

            if t > learning_starts and t % target_network_update_freq == 0:
                # Update target network periodically.
                update_target()

            mean_100ep_reward = round(np.mean(episode_rewards[-101:-1]), 1)
            num_episodes = len(episode_rewards)
            if done and print_freq is not None and len(
                    episode_rewards) % print_freq == 0:
                logger.record_tabular("steps", t)
                logger.record_tabular("episodes", num_episodes)
                logger.record_tabular("mean 100 episode reward",
                                      mean_100ep_reward)
                logger.record_tabular("% time spent exploring",
                                      int(100 * exploration.value(t)))
                logger.dump_tabular()

            if (checkpoint_freq is not None and t > learning_starts
                    and num_episodes > 100 and t % checkpoint_freq == 0):
                if saved_mean_reward is None or mean_100ep_reward > saved_mean_reward:
                    if print_freq is not None:
                        logger.log(
                            "Saving model due to mean reward increase: {} -> {}"
                            .format(saved_mean_reward, mean_100ep_reward))
                    U.save_state(model_file)
                    model_saved = True
                    saved_mean_reward = mean_100ep_reward
        if model_saved:
            if print_freq is not None:
                logger.log("Restored model with mean reward: {}".format(
                    saved_mean_reward))
            U.load_state(model_file)

    return act
示例#3
0
    """This model takes as input an observation and returns values of all actions."""
    with tf.variable_scope(scope, reuse=reuse):
        out = inpt
        out = layers.fully_connected(out, num_outputs=64, activation_fn=tf.nn.tanh)
        out = layers.fully_connected(out, num_outputs=num_actions, activation_fn=None)
        return out


if __name__ == '__main__':
    with U.make_session(num_cpu=8):
        # Create the environment
        env = gym.make("CartPole-v0")
        # Create all the functions necessary to train the model
        act, train, update_target, debug = deepq.build_train(
            make_obs_ph=lambda name: ObservationInput(env.observation_space, name=name),
            q_func=model,
            num_actions=env.action_space.n,
            optimizer=tf.train.AdamOptimizer(learning_rate=5e-4),
        )
        # Create the replay buffer
        replay_buffer = ReplayBuffer(50000)
        # Create the schedule for exploration starting from 1 (every action is random) down to
        # 0.02 (98% of actions are selected according to values predicted by the model).
        exploration = LinearSchedule(schedule_timesteps=10000, initial_p=1.0, final_p=0.02)

        # Initialize the parameters and copy them to the target network.
        U.initialize()
        update_target()

        episode_rewards = [0.0]
        obs = env.reset()
        # for t in itertools.count():
示例#4
0
def learn_continuous_tasks(env,
                           q_func,
                           env_name,
                           dir_path,
                           time_stamp,
                           total_num_episodes,
                           num_actions_pad=33,
                           lr=1e-4,
                           grad_norm_clipping=10,
                           max_timesteps=int(1e8),
                           buffer_size=int(1e6),
                           train_freq=1,
                           batch_size=64,
                           print_freq=10,
                           learning_starts=1000,
                           gamma=0.99,
                           target_network_update_freq=500,
                           prioritized_replay=False,
                           prioritized_replay_alpha=0.6,
                           prioritized_replay_beta0=0.4,
                           prioritized_replay_beta_iters=None,
                           prioritized_replay_eps=int(1e8),
                           num_cpu=16,
                           epsilon_greedy=False,
                           timesteps_std=1e6,
                           initial_std=0.4,
                           final_std=0.05,
                           eval_freq=100,
                           n_eval_episodes=10,
                           eval_std=0.01,
                           log_index=0,
                           log_prefix='q',
                           loss_type="L2",
                           model_file='./',
                           callback=None):
    """Train a branching deepq model to solve continuous control tasks via discretization.
    Current assumptions in the implementation:
    - for solving continuous control domains via discretization (can be adjusted to be compatible with naturally disceret-action domains using 'env.action_space.n')
    - uniform number of sub-actions per action dimension (can be generalized to heterogeneous number of sub-actions across branches)

    Parameters
    -------
    env : gym.Env
        environment to train on
    q_func: (tf.Variable, int, str, bool) -> tf.Variable
        the model that takes the following inputs:
            observation_in: object
                the output of observation placeholder
            num_actions: int
                number of actions
            scope: str
            reuse: bool
                should be passed to outer variable scope
        and returns a tensor of shape (batch_size, num_actions) with values of every action.
    num_actions_pad: int
        number of sub-actions per action dimension (= num of discretization grains/bars + 1)
    lr: float
        learning rate for adam optimizer
    max_timesteps: int
        number of env steps to optimize for
    buffer_size: int
        size of the replay buffer
    exploration_fraction: float
        fraction of entire training period over which the exploration rate is annealed
        0.1 for dqn-baselines
    exploration_final_eps: float
        final value of random action probability
        0.02 for dqn-baselines
    train_freq: int
        update the model every `train_freq` steps.
    batch_size: int
        size of a batched sampled from replay buffer for training
    print_freq: int
        how often to print out training progress
        set to None to disable printing
    learning_starts: int
        how many steps of the model to collect transitions for before learning starts
    gamma: float
        discount factor
    grad_norm_clipping: int
        set None for no clipping
    target_network_update_freq: int
        update the target network every `target_network_update_freq` steps.
    prioritized_replay: True
        if True prioritized replay buffer will be used.
    prioritized_replay_alpha: float
        alpha parameter for prioritized replay buffer
    prioritized_replay_beta0: float
        initial value of beta for prioritized replay buffer
    prioritized_replay_beta_iters: int
        number of iterations over which beta will be annealed from initial value
        to 1.0. If set to None equals to max_timesteps.
    prioritized_replay_eps: float
        epsilon to add to the unified TD error for updating priorities.
        Erratum: The camera-ready copy of this paper incorrectly reported 1e-8.
        The value used to produece the results is 1e8.
    num_cpu: int
        number of cpus to use for training

    dir_path: str
        path for logs and results to be stored in
    callback: (locals, globals) -> None
        function called at every steps with state of the algorithm.
        If callback returns true training stops.

    Returns
    -------
    act: ActWrapper
        Wrapper over act function. Adds ability to save it and load it.
        See header of baselines/deepq/categorical.py for details on the act function.
    """

    sess = U.make_session(num_cpu=num_cpu)
    sess.__enter__()

    def make_obs_ph(name):
        return U.BatchInput(env.observation_space.shape, name=name)

    print('Observation shape:' + str(env.observation_space.shape))

    num_action_grains = num_actions_pad - 1
    num_action_dims = env.action_space.shape[0]
    num_action_streams = num_action_dims
    num_actions = num_actions_pad * num_action_streams  # total numb network outputs for action branching with one action dimension per branch

    print('Number of actions in total:' + str(num_actions))

    act, q_val, train, update_target, debug = deepq.build_train(
        make_obs_ph=make_obs_ph,
        q_func=q_func,
        num_actions=num_actions,
        num_action_streams=num_action_streams,
        batch_size=batch_size,
        optimizer_name="Adam",
        learning_rate=lr,
        grad_norm_clipping=grad_norm_clipping,
        gamma=gamma,
        double_q=True,
        scope="deepq",
        reuse=None,
        loss_type="L2")

    print('TRAIN VARS:')
    print(tf.trainable_variables())

    act_params = {
        'make_obs_ph': make_obs_ph,
        'q_func': q_func,
        'num_actions': num_actions,
        'num_action_streams': num_action_streams,
    }

    print('Create the log writer for TensorBoard visualizations.')
    log_dir = "{}/tensorboard_logs/{}".format(dir_path, env_name)
    if not os.path.exists(log_dir):
        os.makedirs(log_dir)
    score_placeholder = tf.placeholder(tf.float32, [],
                                       name='score_placeholder')
    tf.summary.scalar('score', score_placeholder)
    lr_constant = tf.constant(lr, name='lr_constant')
    tf.summary.scalar('learning_rate', lr_constant)

    eval_placeholder = tf.placeholder(tf.float32, [], name='eval_placeholder')
    eval_summary = tf.summary.scalar('evaluation', eval_placeholder)

    # Create the replay buffer
    if prioritized_replay:
        replay_buffer = PrioritizedReplayBuffer(buffer_size,
                                                alpha=prioritized_replay_alpha)
        if prioritized_replay_beta_iters is None:
            prioritized_replay_beta_iters = max_timesteps
        beta_schedule = LinearSchedule(prioritized_replay_beta_iters,
                                       initial_p=prioritized_replay_beta0,
                                       final_p=1.0)
    else:
        replay_buffer = ReplayBuffer(buffer_size)
        beta_schedule = None

    if epsilon_greedy:
        approximate_num_iters = 2e6 / 4
        exploration = PiecewiseSchedule([(0, 1.0),
                                         (approximate_num_iters / 50, 0.1),
                                         (approximate_num_iters / 5, 0.01)],
                                        outside_value=0.01)
    else:
        exploration = ConstantSchedule(value=0.0)  # greedy policy
        std_schedule = LinearSchedule(schedule_timesteps=timesteps_std,
                                      initial_p=initial_std,
                                      final_p=final_std)

    # Initialize the parameters and copy them to the target network.
    U.initialize()
    update_target()

    # Initialize the parameters used for converting branching, discrete action indeces to continuous actions
    low = env.action_space.low
    high = env.action_space.high
    actions_range = np.subtract(high, low)
    print('###################################')
    print(low)
    print(high)
    print('###################################')

    episode_rewards = []
    reward_sum = 0.0
    time_steps = [0]
    time_spent_exploring = [0]

    prev_time = time.time()
    n_trainings = 0

    # Open a dircetory for recording results
    results_dir = "{}/results/{}".format(dir_path, env_name)
    if not os.path.exists(results_dir):
        os.makedirs(results_dir)

    displayed_mean_reward = None
    score_timesteps = []

    game_scores = []

    def evaluate(step, episode_number):
        global max_eval_reward_mean, model_saved
        print('Evaluate...')
        eval_reward_sum = 0.0
        # Run evaluation episodes
        for eval_episode in range(n_eval_episodes):
            obs = env.reset()
            done = False
            while not done:
                # Choose action
                action_idxes = np.array(
                    act(np.array(obs)[None],
                        stochastic=False))  # deterministic
                actions_greedy = action_idxes / num_action_grains * actions_range + low

                if eval_std == 0.0:
                    action = actions_greedy
                else:
                    action = []
                    for index in range(len(actions_greedy)):
                        a_greedy = actions_greedy[index]
                        out_of_range_action = True
                        while out_of_range_action:
                            a_stoch = np.random.normal(loc=a_greedy,
                                                       scale=eval_std)
                            a_idx_stoch = np.rint(
                                (a_stoch + high[index]) /
                                actions_range[index] * num_action_grains)
                            if a_idx_stoch >= 0 and a_idx_stoch < num_actions_pad:
                                action.append(a_stoch)
                                out_of_range_action = False

                # Step
                obs, rew, done, _ = env.step(action)

                eval_reward_sum += rew

        # Average the rewards and log
        eval_reward_mean = eval_reward_sum / n_eval_episodes
        print(eval_reward_mean, 'over', n_eval_episodes, 'episodes')
        game_scores.append(eval_reward_mean)
        score_timesteps.append(step)

        if max_eval_reward_mean is None or eval_reward_mean > max_eval_reward_mean:
            logger.log(
                "Saving model due to mean eval increase: {} -> {}".format(
                    max_eval_reward_mean, eval_reward_mean))
            U.save_state(model_file)
            model_saved = True
            max_eval_reward_mean = eval_reward_mean
            intact = ActWrapper(act, act_params)

            intact.save(model_file + "_" + str(episode_number) + "_" +
                        str(int(np.round(max_eval_reward_mean))))
            print('Act saved to ' + model_file + "_" + str(episode_number) +
                  "_" + str(int(np.round(max_eval_reward_mean))))

    with tempfile.TemporaryDirectory() as td:
        td = './logs'
        evaluate(0, 0)
        obs = env.reset()

        t = -1
        all_means = []
        q_stats = []
        current_qs = []

        training_game_scores = []
        training_timesteps = []
        while True:
            t += 1
            # Select action and update exploration probability
            action_idxes = np.array(
                act(np.array(obs)[None], update_eps=exploration.value(t)))
            qs = np.array(q_val(np.array(obs)[None],
                                stochastic=False))  # deterministic
            tt = []
            for val in qs:
                tt.append(np.std(val))
            current_qs.append(tt)

            # Convert sub-actions indexes (discrete sub-actions) to continuous controls
            action = action_idxes / num_action_grains * actions_range + low
            if not epsilon_greedy:  # Gaussian noise
                actions_greedy = action
                action_idx_stoch = []
                action = []
                for index in range(len(actions_greedy)):
                    a_greedy = actions_greedy[index]
                    out_of_range_action = True
                    while out_of_range_action:
                        # Sample from a Gaussian with mean at the greedy action and a std following a schedule of choice
                        a_stoch = np.random.normal(loc=a_greedy,
                                                   scale=std_schedule.value(t))
                        # Convert sampled cont action to an action idx
                        a_idx_stoch = np.rint(
                            (a_stoch + high[index]) / actions_range[index] *
                            num_action_grains)
                        # Check if action is in range
                        if a_idx_stoch >= 0 and a_idx_stoch < num_actions_pad:
                            action_idx_stoch.append(a_idx_stoch)
                            action.append(a_stoch)
                            out_of_range_action = False
                action_idxes = action_idx_stoch
            new_obs, rew, done, _ = env.step(np.array(action))
            # Store transition in the replay buffer
            replay_buffer.add(obs, action_idxes, rew, new_obs, float(done))
            obs = new_obs
            reward_sum += rew
            if done:
                obs = env.reset()
                time_spent_exploring[-1] = int(100 * exploration.value(t))
                time_spent_exploring.append(0)
                episode_rewards.append(reward_sum)
                training_game_scores.append(reward_sum)
                training_timesteps.append(t)
                time_steps[-1] = t
                reward_sum = 0.0
                time_steps.append(0)
                q_stats.append(np.mean(current_qs, 0))
                current_qs = []

            if t > learning_starts and t % train_freq == 0:
                # Minimize the error in Bellman's equation on a batch sampled from replay buffer
                if prioritized_replay:
                    experience = replay_buffer.sample(
                        batch_size, beta=beta_schedule.value(t))
                    (obses_t, actions, rewards, obses_tp1, dones, weights,
                     batch_idxes) = experience
                else:
                    obses_t, actions, rewards, obses_tp1, dones = replay_buffer.sample(
                        batch_size)
                    weights, batch_idxes = np.ones_like(rewards), None
                td_errors = train(
                    obses_t, actions, rewards, obses_tp1, dones,
                    weights)  # np.ones_like(rewards)) #TEMP AT NEW
                if prioritized_replay:
                    new_priorities = np.abs(td_errors) + prioritized_replay_eps
                    replay_buffer.update_priorities(batch_idxes,
                                                    new_priorities)
                n_trainings += 1
            if t > learning_starts and t % target_network_update_freq == 0:
                # Update target network periodically
                update_target()
            if len(episode_rewards) == 0:
                mean_100ep_reward = 0
            elif len(episode_rewards) < 100:
                mean_100ep_reward = np.mean(episode_rewards)
            else:
                mean_100ep_reward = np.mean(episode_rewards[-100:])
            all_means.append(mean_100ep_reward)
            num_episodes = len(episode_rewards)
            if done and print_freq is not None and len(
                    episode_rewards) % print_freq == 0:
                logger.record_tabular("steps", t)
                logger.record_tabular("episodes", num_episodes)
                logger.record_tabular("mean 100 episode reward",
                                      mean_100ep_reward)
                logger.record_tabular("% time spent exploring",
                                      int(100 * exploration.value(t)))
                current_time = time.time()
                logger.record_tabular("trainings per second",
                                      n_trainings / (current_time - prev_time))
                logger.dump_tabular()
                n_trainings = 0
                prev_time = current_time
            if t > learning_starts and num_episodes > 100:
                if displayed_mean_reward is None or mean_100ep_reward > displayed_mean_reward:
                    if print_freq is not None:
                        logger.log("Mean reward increase: {} -> {}".format(
                            displayed_mean_reward, mean_100ep_reward))
                    displayed_mean_reward = mean_100ep_reward
                    # Performance evaluation with a greedy policy
            if done and num_episodes % eval_freq == 0:
                evaluate(t + 1, num_episodes)
                obs = env.reset()
            # STOP training
            if num_episodes >= total_num_episodes:
                break
        pickle.dump(q_stats,
                    open(
                        str(log_index) + "q_stat_stds99_" + log_prefix +
                        ".pkl", 'wb'),
                    protocol=pickle.HIGHEST_PROTOCOL)

        pickle.dump(game_scores,
                    open(
                        str(log_index) + "q_stat_scores99_" + log_prefix +
                        ".pkl", 'wb'),
                    protocol=pickle.HIGHEST_PROTOCOL)

    return ActWrapper(act, act_params)
def learn_continuous_tasks(env,
                           q_func,
                           env_name,
                           time_stamp,
                           total_num_episodes,
                           num_actions_pad=33,
                           lr=1e-4,
                           grad_norm_clipping=10,
                           max_timesteps=int(1e8),
                           buffer_size=int(1e6),
                           train_freq=1,
                           batch_size=64,
                           print_freq=10,
                           learning_starts=1000,
                           gamma=0.99,
                           target_network_update_freq=500,
                           prioritized_replay_alpha=0.6,
                           prioritized_replay_beta0=0.4,
                           prioritized_replay_beta_iters=2e6,
                           prioritized_replay_eps=int(1e8),
                           num_cpu=16,
                           timesteps_std=1e6,
                           initial_std=0.4,
                           final_std=0.05,
                           eval_freq=100,
                           n_eval_episodes=10,
                           eval_std=0.01,
                           callback=None):
    """Train a branching deepq model to solve continuous control tasks via discretization.
    Current assumptions in the implementation: 
    - for solving continuous control domains via discretization (can be adjusted to be compatible with naturally disceret-action domains using 'env.action_space.n')
    - uniform number of sub-actions per action dimension (can be generalized to heterogeneous number of sub-actions across branches) 

    Parameters
    -------
    env : gym.Env
        environment to train on
    q_func: (tf.Variable, int, str, bool) -> tf.Variable
        the model that takes the following inputs:
            observation_in: object
                the output of observation placeholder
            num_actions: int
                number of actions
            scope: str
            reuse: bool
                should be passed to outer variable scope
        and returns a tensor of shape (batch_size, num_actions) with values of every action.
    num_actions_pad: int
        number of sub-actions per action dimension (= num of discretization grains/bars + 1)
    lr: float
        learning rate for adam optimizer
    max_timesteps: int
        number of env steps to optimize for
    buffer_size: int
        size of the replay buffer
    exploration_fraction: float
        fraction of entire training period over which the exploration rate is annealed
        0.1 for dqn-baselines
    exploration_final_eps: float
        final value of random action probability
        0.02 for dqn-baselines 
    train_freq: int
        update the model every `train_freq` steps.
    batch_size: int
        size of a batched sampled from replay buffer for training
    print_freq: int
        how often to print out training progress
        set to None to disable printing
    learning_starts: int
        how many steps of the model to collect transitions for before learning starts
    gamma: float
        discount factor
    grad_norm_clipping: int
        set None for no clipping
    target_network_update_freq: int
        update the target network every `target_network_update_freq` steps.
    prioritized_replay: True
        if True prioritized replay buffer will be used.
    prioritized_replay_alpha: float
        alpha parameter for prioritized replay buffer
    prioritized_replay_beta0: float
        initial value of beta for prioritized replay buffer
    prioritized_replay_beta_iters: int
        number of iterations over which beta will be annealed from initial value
        to 1.0. If set to None equals to max_timesteps.
    prioritized_replay_eps: float
        epsilon to add to the unified TD error for updating priorities.
        Erratum: The camera-ready copy of this paper incorrectly reported 1e-8. 
        The value used to produece the results is 1e8.
    num_cpu: int
        number of cpus to use for training
    losses_version: int
        optimization version number
    dir_path: str 
        path for logs and results to be stored in 
    callback: (locals, globals) -> None
        function called at every steps with state of the algorithm.
        If callback returns true training stops.

    Returns
    -------
    act: ActWrapper
        Wrapper over act function. Adds ability to save it and load it.
        See header of baselines/deepq/categorical.py for details on the act function.
    """

    sess = U.make_session(num_cpu=num_cpu)
    sess.__enter__()

    def make_obs_ph(name):
        return U.BatchInput(env.observation_space.shape, name=name)

    num_action_grains = num_actions_pad - 1
    num_action_dims = env.action_space.shape[0]
    num_action_streams = num_action_dims
    num_actions = num_actions_pad * num_action_streams  # total numb network outputs for action branching with one action dimension per branch

    act, train, update_target, debug = deepq.build_train(
        make_obs_ph=make_obs_ph,
        q_func=q_func,
        num_actions=num_actions,
        num_action_streams=num_action_streams,
        batch_size=batch_size,
        learning_rate=lr,
        grad_norm_clipping=grad_norm_clipping,
        gamma=gamma,
        scope="deepq",
        reuse=None)
    act_params = {
        'make_obs_ph': make_obs_ph,
        'q_func': q_func,
        'num_actions': num_actions,
        'num_action_streams': num_action_streams,
    }

    # prioritized_replay: create the replay buffer
    replay_buffer = PrioritizedReplayBuffer(buffer_size,
                                            alpha=prioritized_replay_alpha)
    beta_schedule = LinearSchedule(prioritized_replay_beta_iters,
                                   initial_p=prioritized_replay_beta0,
                                   final_p=1.0)

    # epsilon_greedy = False: just greedy policy
    exploration = ConstantSchedule(value=0.0)  # greedy policy
    std_schedule = LinearSchedule(schedule_timesteps=timesteps_std,
                                  initial_p=initial_std,
                                  final_p=final_std)

    # Initialize the parameters and copy them to the target network.
    U.initialize()
    update_target()

    # Initialize the parameters used for converting branching, discrete action indeces to continuous actions
    low = env.action_space.low
    high = env.action_space.high
    actions_range = np.subtract(high, low)

    episode_rewards = []
    reward_sum = 0.0
    num_episodes = 0
    time_steps = [0]
    time_spent_exploring = [0]

    prev_time = time.time()
    n_trainings = 0

    # Set up on-demand rendering of Gym environments using keyboard controls: 'r'ender or 's'top
    import termios, fcntl, sys
    fd = sys.stdin.fileno()
    oldterm = termios.tcgetattr(fd)
    newattr = termios.tcgetattr(fd)
    newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
    render = False

    displayed_mean_reward = None

    def evaluate(step, episode_number):
        global max_eval_reward_mean, model_saved
        print('Evaluate...')
        eval_reward_sum = 0.0
        # Run evaluation episodes
        for eval_episode in range(n_eval_episodes):
            obs = env.reset()
            done = False
            while not done:
                # Choose action
                action_idxes = np.array(
                    act(np.array(obs)[None],
                        stochastic=False))  # deterministic
                actions_greedy = action_idxes / num_action_grains * actions_range + low

                if eval_std == 0.0:
                    action = actions_greedy
                else:
                    action = []
                    for index in range(len(actions_greedy)):
                        a_greedy = actions_greedy[index]
                        out_of_range_action = True
                        while out_of_range_action:
                            a_stoch = np.random.normal(loc=a_greedy,
                                                       scale=eval_std)
                            a_idx_stoch = np.rint(
                                (a_stoch + high[index]) /
                                actions_range[index] * num_action_grains)
                            if a_idx_stoch >= 0 and a_idx_stoch < num_actions_pad:
                                action.append(a_stoch)
                                out_of_range_action = False

                # Step
                obs, rew, done, _ = env.step(action)
                eval_reward_sum += rew

        # Average the rewards and log
        eval_reward_mean = eval_reward_sum / n_eval_episodes
        print(eval_reward_mean, 'over', n_eval_episodes, 'episodes')

        with open("results/{}_{}_eval.csv".format(time_stamp, env_name),
                  "a") as eval_fw:
            eval_writer = csv.writer(
                eval_fw,
                delimiter="\t",
                lineterminator="\n",
            )
            eval_writer.writerow([episode_number, step, eval_reward_mean])

        if max_eval_reward_mean is None or eval_reward_mean > max_eval_reward_mean:
            logger.log(
                "Saving model due to mean eval increase: {} -> {}".format(
                    max_eval_reward_mean, eval_reward_mean))
            U.save_state(model_file)
            model_saved = True
            max_eval_reward_mean = eval_reward_mean

    with tempfile.TemporaryDirectory() as td:
        model_file = os.path.join(td, "model")

        evaluate(0, 0)
        obs = env.reset()

        with open("results/{}_{}.csv".format(time_stamp, env_name), "w") as fw:
            writer = csv.writer(
                fw,
                delimiter="\t",
                lineterminator="\n",
            )

            t = -1
            while True:
                t += 1

                # Select action and update exploration probability
                action_idxes = np.array(
                    act(np.array(obs)[None], update_eps=exploration.value(t)))

                # Convert sub-actions indexes (discrete sub-actions) to continuous controls
                action = action_idxes / num_action_grains * actions_range + low

                # epsilon_greedy = False: use Gaussian noise
                actions_greedy = action
                action_idx_stoch = []
                action = []
                for index in range(len(actions_greedy)):
                    a_greedy = actions_greedy[index]
                    out_of_range_action = True
                    while out_of_range_action:
                        # Sample from a Gaussian with mean at the greedy action and a std following a schedule of choice
                        a_stoch = np.random.normal(loc=a_greedy,
                                                   scale=std_schedule.value(t))

                        # Convert sampled cont action to an action idx
                        a_idx_stoch = np.rint(
                            (a_stoch + high[index]) / actions_range[index] *
                            num_action_grains)

                        # Check if action is in range
                        if a_idx_stoch >= 0 and a_idx_stoch < num_actions_pad:
                            action_idx_stoch.append(a_idx_stoch)
                            action.append(a_stoch)
                            out_of_range_action = False

                action_idxes = action_idx_stoch

                new_obs, rew, done, _ = env.step(action)

                # On-demand rendering
                if (t + 1) % 100 == 0:
                    # TO DO better?
                    termios.tcsetattr(fd, termios.TCSANOW, newattr)
                    oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
                    fcntl.fcntl(fd, fcntl.F_SETFL, oldflags | os.O_NONBLOCK)
                    try:
                        try:
                            c = sys.stdin.read(1)
                            if c == 'r':
                                print()
                                print('Rendering begins...')
                                render = True
                            elif c == 's':
                                print()
                                print('Stop rendering!')
                                render = False
                                env.render(close=True)
                        except IOError:
                            pass
                    finally:
                        termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)
                        fcntl.fcntl(fd, fcntl.F_SETFL, oldflags)

                # Visualize Gym environment on render
                if render: env.render()

                # Store transition in the replay buffer
                replay_buffer.add(obs, action_idxes, rew, new_obs, float(done))
                obs = new_obs

                reward_sum += rew
                if done:
                    obs = env.reset()
                    time_spent_exploring[-1] = int(100 * exploration.value(t))
                    time_spent_exploring.append(0)
                    episode_rewards.append(reward_sum)
                    time_steps[-1] = t
                    reward_sum = 0.0
                    time_steps.append(0)
                    # Frequently log to file
                    writer.writerow(
                        [len(episode_rewards), t, episode_rewards[-1]])

                if t > learning_starts and t % train_freq == 0:
                    # Minimize the error in Bellman's equation on a batch sampled from replay buffer
                    # prioritized_replay
                    experience = replay_buffer.sample(
                        batch_size, beta=beta_schedule.value(t))
                    (obses_t, actions, rewards, obses_tp1, dones, weights,
                     batch_idxes) = experience

                    td_errors = train(
                        obses_t, actions, rewards, obses_tp1, dones,
                        weights)  #np.ones_like(rewards)) #TEMP AT NEW

                    # prioritized_replay
                    new_priorities = np.abs(td_errors) + prioritized_replay_eps
                    replay_buffer.update_priorities(batch_idxes,
                                                    new_priorities)

                    n_trainings += 1

                if t > learning_starts and t % target_network_update_freq == 0:
                    # Update target network periodically
                    update_target()

                if len(episode_rewards) == 0: mean_100ep_reward = 0
                elif len(episode_rewards) < 100:
                    mean_100ep_reward = np.mean(episode_rewards)
                else:
                    mean_100ep_reward = np.mean(episode_rewards[-100:])

                num_episodes = len(episode_rewards)
                if done and print_freq is not None and len(
                        episode_rewards) % print_freq == 0:
                    logger.record_tabular("steps", t)
                    logger.record_tabular("episodes", num_episodes)
                    logger.record_tabular("mean 100 episode reward",
                                          mean_100ep_reward)
                    logger.record_tabular("% time spent exploring",
                                          int(100 * exploration.value(t)))
                    current_time = time.time()
                    logger.record_tabular(
                        "trainings per second",
                        n_trainings / (current_time - prev_time))
                    logger.dump_tabular()
                    n_trainings = 0
                    prev_time = current_time

                if t > learning_starts and num_episodes > 100:
                    if displayed_mean_reward is None or mean_100ep_reward > displayed_mean_reward:
                        if print_freq is not None:
                            logger.log("Mean reward increase: {} -> {}".format(
                                displayed_mean_reward, mean_100ep_reward))
                        displayed_mean_reward = mean_100ep_reward

                # Performance evaluation with a greedy policy
                if done and num_episodes % eval_freq == 0:
                    evaluate(t + 1, num_episodes)
                    obs = env.reset()

                # STOP training
                if num_episodes >= total_num_episodes:
                    break

            if model_saved:
                logger.log("Restore model with mean eval: {}".format(
                    max_eval_reward_mean))
                U.load_state(model_file)

    data_to_log = {
        'time_steps': time_steps,
        'episode_rewards': episode_rewards,
        'time_spent_exploring': time_spent_exploring
    }

    # Write to file the episodic rewards, number of steps, and the time spent exploring
    with open("results/{}_{}.txt".format(time_stamp, env_name), 'wb') as fp:
        pickle.dump(data_to_log, fp)

    return ActWrapper(act, act_params)