Esempio n. 1
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 def testActionIsInRange(self):
     policy = gaussian_policy.GaussianPolicy(self._wrapped_policy)
     action_step = policy.action(self._time_step_batch)
     self.assertEqual(action_step.action.shape.as_list(), [2, 1])
     self.assertEqual(action_step.action.dtype, tf.float32)
     self.evaluate(tf.compat.v1.global_variables_initializer())
     self.evaluate(tf.compat.v1.local_variables_initializer())
     actions_ = self.evaluate(action_step.action)
     self.assertTrue(np.all(actions_ >= self._action_spec.minimum))
     self.assertTrue(np.all(actions_ <= self._action_spec.maximum))
Esempio n. 2
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  def testActionAddsGaussianNoise(self):
    policy = gaussian_policy.GaussianPolicy(self._wrapped_policy, clip=False)
    action_step = policy.action(self._time_step_batch)
    wrapped_action_step = self._wrapped_policy.action(self._time_step_batch)

    self.evaluate(tf.compat.v1.global_variables_initializer())
    self.evaluate(tf.compat.v1.local_variables_initializer())
    actions_ = self.evaluate(action_step.action)
    wrapped_policy_actions_ = self.evaluate(wrapped_action_step.action)

    self.assertTrue(np.linalg.norm(actions_ - wrapped_policy_actions_) > 0)
Esempio n. 3
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    def testActionList(self):
        action_spec = [self._action_spec]
        actor_network = DummyActionNet(self._obs_spec, action_spec)
        self._wrapped_policy = actor_policy.ActorPolicy(
            time_step_spec=self._time_step_spec,
            action_spec=action_spec,
            actor_network=actor_network,
            clip=False)

        policy = gaussian_policy.GaussianPolicy(self._wrapped_policy)
        action_step = policy.action(self._time_step_batch)
        self.assertEqual(action_step.action[0].shape.as_list(), [2, 1])
        self.assertEqual(action_step.action[0].dtype, tf.float32)
        self.evaluate(tf.compat.v1.global_variables_initializer())
        self.evaluate(tf.compat.v1.local_variables_initializer())
        actions_ = self.evaluate(action_step.action)
        self.assertTrue(np.all(actions_[0] >= self._action_spec.minimum))
        self.assertTrue(np.all(actions_[0] <= self._action_spec.maximum))
Esempio n. 4
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  def __init__(self,
               time_step_spec,
               action_spec,
               actor_network,
               critic_network,
               actor_optimizer,
               critic_optimizer,
               exploration_noise_std=0.1,
               critic_network_2=None,
               target_actor_network=None,
               target_critic_network=None,
               target_critic_network_2=None,
               target_update_tau=1.0,
               target_update_period=1,
               actor_update_period=1,
               dqda_clipping=None,
               td_errors_loss_fn=None,
               gamma=1.0,
               reward_scale_factor=1.0,
               target_policy_noise=0.2,
               target_policy_noise_clip=0.5,
               gradient_clipping=None,
               debug_summaries=False,
               summarize_grads_and_vars=False,
               train_step_counter=None,
               name=None):
    """Creates a Td3Agent Agent.

    Args:
      time_step_spec: A `TimeStep` spec of the expected time_steps.
      action_spec: A nest of BoundedTensorSpec representing the actions.
      actor_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call(observation, step_type).
      critic_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call(observation, action, step_type).
      actor_optimizer: The default optimizer to use for the actor network.
      critic_optimizer: The default optimizer to use for the critic network.
      exploration_noise_std: Scale factor on exploration policy noise.
      critic_network_2: (Optional.)  A `tf_agents.network.Network` to be used as
        the second critic network during Q learning.  The weights from
        `critic_network` are copied if this is not provided.
      target_actor_network: (Optional.)  A `tf_agents.network.Network` to be
        used as the target actor network during Q learning. Every
        `target_update_period` train steps, the weights from `actor_network` are
        copied (possibly withsmoothing via `target_update_tau`) to `
        target_actor_network`.  If `target_actor_network` is not provided, it is
        created by making a copy of `actor_network`, which initializes a new
        network with the same structure and its own layers and weights.
        Performing a `Network.copy` does not work when the network instance
        already has trainable parameters (e.g., has already been built, or when
        the network is sharing layers with another).  In these cases, it is up
        to you to build a copy having weights that are not shared with the
        original `actor_network`, so that this can be used as a target network.
        If you provide a `target_actor_network` that shares any weights with
        `actor_network`, a warning will be logged but no exception is thrown.
      target_critic_network: (Optional.) Similar network as target_actor_network
        but for the critic_network. See documentation for target_actor_network.
      target_critic_network_2: (Optional.) Similar network as
        target_actor_network but for the critic_network_2. See documentation for
        target_actor_network. Will only be used if 'critic_network_2' is also
        specified.
      target_update_tau: Factor for soft update of the target networks.
      target_update_period: Period for soft update of the target networks.
      actor_update_period: Period for the optimization step on actor network.
      dqda_clipping: A scalar or float clips the gradient dqda element-wise
        between [-dqda_clipping, dqda_clipping]. Default is None representing no
        clippiing.
      td_errors_loss_fn:  A function for computing the TD errors loss. If None,
        a default value of elementwise huber_loss is used.
      gamma: A discount factor for future rewards.
      reward_scale_factor: Multiplicative scale for the reward.
      target_policy_noise: Scale factor on target action noise
      target_policy_noise_clip: Value to clip noise.
      gradient_clipping: Norm length to clip gradients.
      debug_summaries: A bool to gather debug summaries.
      summarize_grads_and_vars: If True, gradient and network variable summaries
        will be written during training.
      train_step_counter: An optional counter to increment every time the train
        op is run.  Defaults to the global_step.
      name: The name of this agent. All variables in this module will fall under
        that name. Defaults to the class name.
    """
    tf.Module.__init__(self, name=name)
    self._actor_network = actor_network
    actor_network.create_variables()
    if target_actor_network:
      target_actor_network.create_variables()
    self._target_actor_network = common.maybe_copy_target_network_with_checks(
        self._actor_network, target_actor_network, 'TargetActorNetwork')

    self._critic_network_1 = critic_network
    critic_network.create_variables()
    if target_critic_network:
      target_critic_network.create_variables()
    self._target_critic_network_1 = (
        common.maybe_copy_target_network_with_checks(self._critic_network_1,
                                                     target_critic_network,
                                                     'TargetCriticNetwork1'))

    if critic_network_2 is not None:
      self._critic_network_2 = critic_network_2
    else:
      self._critic_network_2 = critic_network.copy(name='CriticNetwork2')
      # Do not use target_critic_network_2 if critic_network_2 is None.
      target_critic_network_2 = None
    self._critic_network_2.create_variables()
    if target_critic_network_2:
      target_critic_network_2.create_variables()
    self._target_critic_network_2 = (
        common.maybe_copy_target_network_with_checks(self._critic_network_2,
                                                     target_critic_network_2,
                                                     'TargetCriticNetwork2'))

    self._actor_optimizer = actor_optimizer
    self._critic_optimizer = critic_optimizer

    self._exploration_noise_std = exploration_noise_std
    self._target_update_tau = target_update_tau
    self._target_update_period = target_update_period
    self._actor_update_period = actor_update_period
    self._dqda_clipping = dqda_clipping
    self._td_errors_loss_fn = (
        td_errors_loss_fn or common.element_wise_huber_loss)
    self._gamma = gamma
    self._reward_scale_factor = reward_scale_factor
    self._target_policy_noise = target_policy_noise
    self._target_policy_noise_clip = target_policy_noise_clip
    self._gradient_clipping = gradient_clipping

    self._update_target = self._get_target_updater(target_update_tau,
                                                   target_update_period)

    policy = actor_policy.ActorPolicy(
        time_step_spec=time_step_spec,
        action_spec=action_spec,
        actor_network=self._actor_network,
        clip=True)
    collect_policy = actor_policy.ActorPolicy(
        time_step_spec=time_step_spec,
        action_spec=action_spec,
        actor_network=self._actor_network,
        clip=False)
    collect_policy = gaussian_policy.GaussianPolicy(
        collect_policy, scale=self._exploration_noise_std, clip=True)

    super(Td3Agent, self).__init__(
        time_step_spec,
        action_spec,
        policy,
        collect_policy,
        train_sequence_length=2 if not self._actor_network.state_spec else None,
        debug_summaries=debug_summaries,
        summarize_grads_and_vars=summarize_grads_and_vars,
        train_step_counter=train_step_counter)
Esempio n. 5
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  def __init__(self,
               time_step_spec,
               action_spec,
               actor_network,
               critic_network,
               actor_optimizer,
               critic_optimizer,
               exploration_noise_std=0.1,
               target_update_tau=1.0,
               target_update_period=1,
               actor_update_period=1,
               dqda_clipping=None,
               td_errors_loss_fn=None,
               gamma=1.0,
               reward_scale_factor=1.0,
               target_policy_noise=0.2,
               target_policy_noise_clip=0.5,
               gradient_clipping=None,
               debug_summaries=False,
               summarize_grads_and_vars=False,
               train_step_counter=None,
               name=None):
    """Creates a Td3Agent Agent.

    Args:
      time_step_spec: A `TimeStep` spec of the expected time_steps.
      action_spec: A nest of BoundedTensorSpec representing the actions.
      actor_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call(observation, step_type).
      critic_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call(observation, action, step_type).
      actor_optimizer: The default optimizer to use for the actor network.
      critic_optimizer: The default optimizer to use for the critic network.
      exploration_noise_std: Scale factor on exploration policy noise.
      target_update_tau: Factor for soft update of the target networks.
      target_update_period: Period for soft update of the target networks.
      actor_update_period: Period for the optimization step on actor network.
      dqda_clipping: A scalar or float clips the gradient dqda element-wise
        between [-dqda_clipping, dqda_clipping]. Default is None representing no
        clippiing.
      td_errors_loss_fn:  A function for computing the TD errors loss. If None,
        a default value of elementwise huber_loss is used.
      gamma: A discount factor for future rewards.
      reward_scale_factor: Multiplicative scale for the reward.
      target_policy_noise: Scale factor on target action noise
      target_policy_noise_clip: Value to clip noise.
      gradient_clipping: Norm length to clip gradients.
      debug_summaries: A bool to gather debug summaries.
      summarize_grads_and_vars: If True, gradient and network variable summaries
        will be written during training.
      train_step_counter: An optional counter to increment every time the train
        op is run.  Defaults to the global_step.
      name: The name of this agent. All variables in this module will fall
        under that name. Defaults to the class name.
    """
    tf.Module.__init__(self, name=name)
    self._actor_network = actor_network
    self._target_actor_network = actor_network.copy(
        name='TargetActorNetwork')

    self._critic_network_1 = critic_network
    self._target_critic_network_1 = critic_network.copy(
        name='TargetCriticNetwork1')

    self._critic_network_2 = critic_network.copy(name='CriticNetwork2')
    self._target_critic_network_2 = critic_network.copy(
        name='TargetCriticNetwork2')

    self._actor_optimizer = actor_optimizer
    self._critic_optimizer = critic_optimizer

    self._exploration_noise_std = exploration_noise_std
    self._target_update_tau = target_update_tau
    self._target_update_period = target_update_period
    self._actor_update_period = actor_update_period
    self._dqda_clipping = dqda_clipping
    self._td_errors_loss_fn = (
        td_errors_loss_fn or common.element_wise_huber_loss)
    self._gamma = gamma
    self._reward_scale_factor = reward_scale_factor
    self._target_policy_noise = target_policy_noise
    self._target_policy_noise_clip = target_policy_noise_clip
    self._gradient_clipping = gradient_clipping

    self._update_target = self._get_target_updater(
        target_update_tau, target_update_period)

    policy = actor_policy.ActorPolicy(
        time_step_spec=time_step_spec, action_spec=action_spec,
        actor_network=self._actor_network, clip=True)
    collect_policy = actor_policy.ActorPolicy(
        time_step_spec=time_step_spec, action_spec=action_spec,
        actor_network=self._actor_network, clip=False)
    collect_policy = gaussian_policy.GaussianPolicy(
        collect_policy,
        scale=self._exploration_noise_std,
        clip=True)

    super(Td3Agent, self).__init__(
        time_step_spec,
        action_spec,
        policy,
        collect_policy,
        train_sequence_length=2 if not self._actor_network.state_spec else None,
        debug_summaries=debug_summaries,
        summarize_grads_and_vars=summarize_grads_and_vars,
        train_step_counter=train_step_counter)
Esempio n. 6
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 def testBuild(self):
     policy = gaussian_policy.GaussianPolicy(self._wrapped_policy)
     self.assertEqual(policy.time_step_spec, self._time_step_spec)
     self.assertEqual(policy.action_spec, self._action_spec)
     self.assertEqual(len(policy.variables()), 2)
Esempio n. 7
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    def __init__(self,
                 time_step_spec,
                 action_spec,
                 actor_network,
                 critic_network,
                 actor_optimizer=None,
                 critic_optimizer=None,
                 exploration_noise_stddev=2.0,
                 target_actor_network=None,
                 target_critic_network=None,
                 target_update_tau=0.001,
                 target_update_period=1,
                 dqda_clipping=None,
                 td_errors_loss_fn=tf.math.squared_difference,
                 gamma=1.0,
                 reward_scale_factor=1.0,
                 gradient_clipping=None,
                 debug_summaries=False,
                 summarize_grads_and_vars=False,
                 train_step_counter=None,
                 name=None):
        """Creates a DDPG Agent.

    Args:
      time_step_spec: A `TimeStep` spec of the expected time_steps.
      action_spec: A nest of BoundedTensorSpec representing the actions.
      actor_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call(observation, step_type[, policy_state])
        and should return (action, new_state).
      critic_network: A tf_agents.network.Network to be used by the agent. The
        network will be called with call((observation, action), step_type[,
        policy_state]) and should return (q_value, new_state).
      actor_optimizer: The optimizer to use for the actor network.
      critic_optimizer: The optimizer to use for the critic network.
      ou_stddev: Standard deviation for the Ornstein-Uhlenbeck (OU) noise added
        in the default collect policy.
      ou_damping: Damping factor for the OU noise added in the default collect
        policy.
      target_actor_network: (Optional.)  A `tf_agents.network.Network` to be
        used as the actor target network during Q learning.  Every
        `target_update_period` train steps, the weights from `actor_network` are
        copied (possibly withsmoothing via `target_update_tau`) to `
        target_q_network`.

        If `target_actor_network` is not provided, it is created by making a
        copy of `actor_network`, which initializes a new network with the same
        structure and its own layers and weights.

        Performing a `Network.copy` does not work when the network instance
        already has trainable parameters (e.g., has already been built, or
        when the network is sharing layers with another).  In these cases, it is
        up to you to build a copy having weights that are not
        shared with the original `actor_network`, so that this can be used as a
        target network.  If you provide a `target_actor_network` that shares any
        weights with `actor_network`, a warning will be logged but no exception
        is thrown.
      target_critic_network: (Optional.) Similar network as target_actor_network
         but for the critic_network. See documentation for target_actor_network.
      target_update_tau: Factor for soft update of the target networks.
      target_update_period: Period for soft update of the target networks.
      dqda_clipping: when computing the actor loss, clips the gradient dqda
        element-wise between [-dqda_clipping, dqda_clipping]. Does not perform
        clipping if dqda_clipping == 0.
      td_errors_loss_fn:  A function for computing the TD errors loss. If None,
        a default value of elementwise huber_loss is used.
      gamma: A discount factor for future rewards.
      reward_scale_factor: Multiplicative scale for the reward.
      gradient_clipping: Norm length to clip gradients.
      debug_summaries: A bool to gather debug summaries.
      summarize_grads_and_vars: If True, gradient and network variable summaries
        will be written during training.
      train_step_counter: An optional counter to increment every time the train
        op is run.  Defaults to the global_step.
      name: The name of this agent. All variables in this module will fall
        under that name. Defaults to the class name.
    """
        tf.Module.__init__(self, name=name)
        self._actor_network = actor_network
        actor_network.create_variables()
        if target_actor_network:
            target_actor_network.create_variables()
        self._target_actor_network = common.maybe_copy_target_network_with_checks(
            self._actor_network, target_actor_network, 'TargetActorNetwork')
        self._critic_network = critic_network
        critic_network.create_variables()
        if target_critic_network:
            target_critic_network.create_variables()
        self._target_critic_network = common.maybe_copy_target_network_with_checks(
            self._critic_network, target_critic_network, 'TargetCriticNetwork')

        self._actor_optimizer = actor_optimizer
        self._critic_optimizer = critic_optimizer

        self._standard_normal = ds.Normal(0, 1)
        self._target_update_tau = target_update_tau
        self._target_update_period = target_update_period
        self._dqda_clipping = dqda_clipping
        self._td_errors_loss_fn = (td_errors_loss_fn
                                   or common.element_wise_huber_loss)
        self._gamma = gamma
        self._reward_scale_factor = reward_scale_factor
        self._gradient_clipping = gradient_clipping

        self._update_target = self._get_target_updater(target_update_tau,
                                                       target_update_period)

        policy = agents.WcpgPolicy(
            time_step_spec=time_step_spec,
            action_spec=action_spec,
            alpha_sampler=lambda: np.random.uniform(0.1, 0.3),
            actor_network=self._actor_network,
            clip=True)
        collect_policy = agents.WcpgPolicy(time_step_spec=time_step_spec,
                                           action_spec=action_spec,
                                           actor_network=self._actor_network,
                                           clip=False)
        collect_policy = gaussian_policy.GaussianPolicy(
            collect_policy, scale=exploration_noise_stddev, clip=True)

        super(ddpg_agent.DdpgAgent,
              self).__init__(time_step_spec,
                             action_spec,
                             policy,
                             collect_policy,
                             train_sequence_length=2
                             if not self._actor_network.state_spec else None,
                             debug_summaries=debug_summaries,
                             summarize_grads_and_vars=summarize_grads_and_vars,
                             train_step_counter=train_step_counter)
Esempio n. 8
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def train_and_evaluate_ACagent(tf_agent,
                               train_env=None,
                               eval_env=None,
                               num_iterations=None,
                               batch_size=32,
                               replay_buffer_capacity=1000,
                               name='agent'):

    if train_env is None:
        raise ValueError(
            "train_env is None! Environment should be implemented")

    if eval_env is None:
        raise ValueError(
            "eval_env is None! Environment for evaluation should be implemented"
        )

    if num_iterations is None:
        raise ValueError("Number of iterations should be implemented!")

    tf_agent.initialize()

    initial_collect_steps = 1
    collect_steps_per_iteration = 1

    print('Initial collect step is', initial_collect_steps)
    print('collect steps per iteration', collect_steps_per_iteration)
    print('batch size is ', batch_size)
    print('replay buffer capacity is', replay_buffer_capacity)

    eval_policy = tf_agent.policy
    collect_policy = gaussian_policy.GaussianPolicy(tf_agent.collect_policy)

    replay_buffer = tf_uniform_replay_buffer.TFUniformReplayBuffer(
        data_spec=tf_agent.collect_data_spec,
        batch_size=1,
        max_length=replay_buffer_capacity)

    initial_collect_driver = dynamic_step_driver.DynamicStepDriver(
        train_env,
        collect_policy,
        observers=[replay_buffer.add_batch],
        num_steps=initial_collect_steps)

    initial_collect_driver.run()

    collect_driver = dynamic_step_driver.DynamicStepDriver(
        train_env,
        collect_policy,
        observers=[replay_buffer.add_batch],
        num_steps=collect_steps_per_iteration)

    tf_agent.train = common.function(tf_agent.train)
    collect_driver.run = common.function(collect_driver.run)

    # Reset the train step
    tf_agent.train_step_counter.assign(0)

    # Evalute the agent's policy once before training
    avg_return = compute_avg_return(eval_env, eval_policy)
    train_return = compute_avg_return(train_env, eval_policy)
    returns = [(0, avg_return)]
    losses = []
    train_returns = [train_return]

    for _ in range(num_iterations):
        # Collect a few steps using collect_policy and svae to the replay buffer.
        for _ in range(collect_steps_per_iteration):
            collect_driver.run()

        dataset = replay_buffer.as_dataset(batch_size, 2)
        iterator = iter(dataset)
        # Sample a batch of data from the buffer and update the agent's network
        experience, _ = next(iterator)
        train_loss = tf_agent.train(experience)

        step = tf_agent.train_step_counter.numpy()

        log_interval = 50
        eval_interval = 50

        if step % log_interval == 0:
            print('step = {0}: loss = {1}'.format(step, train_loss.loss))
            losses.append((step, train_loss.loss))

        if step % eval_interval == 0:
            eval_policy = tf_agent.policy
            avg_return = compute_avg_return(eval_env, eval_policy)
            train_avg_return = compute_avg_return(train_env, eval_policy)

            print('step = {0}: Average Return = {1}'.format(step, avg_return))
            returns.append((step, avg_return))
            train_returns.append(train_avg_return)

    saver = PolicySaver(tf_agent.policy, batch_size=None)
    saver.save(r'C:\Users\DELL\Desktop\Python\\' + name + "policy_%d" % step)

    steps_list = [r[0] for r in returns]
    rewards_list = [r[1] for r in returns]
    loss_steps_list = [l[0] for l in losses]
    loss_list = [l[1] for l in losses]

    return steps_list, rewards_list, name, loss_steps_list, loss_list, train_returns
Esempio n. 9
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def get_env_and_policy(load_dir,
                       env_name,
                       alpha,
                       env_seed=0,
                       tabular_obs=False):
    if env_name == 'taxi':
        env = taxi.Taxi(tabular_obs=tabular_obs)
        env.seed(env_seed)
        policy_fn, policy_info_spec = taxi.get_taxi_policy(load_dir,
                                                           env,
                                                           alpha=alpha,
                                                           py=False)
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
        policy = common_lib.TFAgentsWrappedPolicy(tf_env.time_step_spec(),
                                                  tf_env.action_spec(),
                                                  policy_fn,
                                                  policy_info_spec,
                                                  emit_log_probability=True)
    elif env_name == 'grid':
        env = navigation.GridWalk(tabular_obs=tabular_obs)
        env.seed(env_seed)
        policy_fn, policy_info_spec = navigation.get_navigation_policy(
            env, epsilon_explore=0.1 + 0.6 * (1 - alpha), py=False)
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
        policy = common_lib.TFAgentsWrappedPolicy(tf_env.time_step_spec(),
                                                  tf_env.action_spec(),
                                                  policy_fn,
                                                  policy_info_spec,
                                                  emit_log_probability=True)
    elif env_name == 'tree':
        env = tree.Tree(branching=2, depth=10)
        env.seed(env_seed)
        policy_fn, policy_info_spec = tree.get_tree_policy(
            env, epsilon_explore=0.1 + 0.8 * (1 - alpha), py=False)
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
        policy = common_lib.TFAgentsWrappedPolicy(tf_env.time_step_spec(),
                                                  tf_env.action_spec(),
                                                  policy_fn,
                                                  policy_info_spec,
                                                  emit_log_probability=True)
    elif env_name.startswith('bandit'):
        num_arms = int(env_name[6:]) if len(env_name) > 6 else 2
        env = bandit.Bandit(num_arms=num_arms)
        env.seed(env_seed)
        policy_fn, policy_info_spec = bandit.get_bandit_policy(
            env, epsilon_explore=1 - alpha, py=False)
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
        policy = common_lib.TFAgentsWrappedPolicy(tf_env.time_step_spec(),
                                                  tf_env.action_spec(),
                                                  policy_fn,
                                                  policy_info_spec,
                                                  emit_log_probability=True)
    elif env_name == 'small_tree':
        env = tree.Tree(branching=2, depth=3, loop=True)
        env.seed(env_seed)
        policy_fn, policy_info_spec = tree.get_tree_policy(
            env, epsilon_explore=0.1 + 0.8 * (1 - alpha), py=False)
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
        policy = common_lib.TFAgentsWrappedPolicy(tf_env.time_step_spec(),
                                                  tf_env.action_spec(),
                                                  policy_fn,
                                                  policy_info_spec,
                                                  emit_log_probability=True)
    elif env_name == 'CartPole-v0':
        tf_env, policy = get_env_and_dqn_policy(
            env_name,
            os.path.join(load_dir, 'CartPole-v0', 'train', 'policy'),
            env_seed=env_seed,
            epsilon=0.3 + 0.15 * (1 - alpha))
    elif env_name == 'cartpole':  # Infinite-horizon cartpole.
        tf_env, policy = get_env_and_dqn_policy(
            'CartPole-v0',
            os.path.join(load_dir, 'CartPole-v0-250', 'train', 'policy'),
            env_seed=env_seed,
            epsilon=0.3 + 0.15 * (1 - alpha))
        env = InfiniteCartPole()
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
    elif env_name == 'FrozenLake-v0':
        tf_env, policy = get_env_and_dqn_policy('FrozenLake-v0',
                                                os.path.join(
                                                    load_dir, 'FrozenLake-v0',
                                                    'train', 'policy'),
                                                env_seed=env_seed,
                                                epsilon=0.2 * (1 - alpha),
                                                ckpt_file='ckpt-100000')
    elif env_name == 'frozenlake':  # Infinite-horizon frozenlake.
        tf_env, policy = get_env_and_dqn_policy('FrozenLake-v0',
                                                os.path.join(
                                                    load_dir, 'FrozenLake-v0',
                                                    'train', 'policy'),
                                                env_seed=env_seed,
                                                epsilon=0.2 * (1 - alpha),
                                                ckpt_file='ckpt-100000')
        env = InfiniteFrozenLake()
        tf_env = tf_py_environment.TFPyEnvironment(gym_wrapper.GymWrapper(env))
    elif env_name in ['Reacher-v2', 'reacher']:
        if env_name == 'Reacher-v2':
            env = suites.load_mujoco(env_name)
        else:
            env = gym_wrapper.GymWrapper(InfiniteReacher())
        env.seed(env_seed)
        tf_env = tf_py_environment.TFPyEnvironment(env)
        sac_policy = get_sac_policy(tf_env)
        directory = os.path.join(load_dir, 'Reacher-v2', 'train', 'policy')
        policy = load_policy(sac_policy, env_name, directory)
        policy = gaussian_policy.GaussianPolicy(policy, 0.4 - 0.3 * alpha)
    elif env_name == 'HalfCheetah-v2':
        env = suites.load_mujoco(env_name)
        env.seed(env_seed)
        tf_env = tf_py_environment.TFPyEnvironment(env)
        sac_policy = get_sac_policy(tf_env)
        directory = os.path.join(load_dir, env_name, 'train', 'policy')
        policy = load_policy(sac_policy, env_name, directory)
        policy = gaussian_policy.GaussianPolicy(policy, 0.2 - 0.1 * alpha)
    else:
        raise ValueError('Unrecognized environment %s.' % env_name)

    return tf_env, policy