Exemplo n.º 1
0
    def setup_model(self):

        with SetVerbosity(self.verbose):
            assert not isinstance(self.action_space, gym.spaces.Box), \
                "Error: DQN cannot output a gym.spaces.Box action space."

            # If the policy is wrap in functool.partial (e.g. to disable dueling)
            # unwrap it to check the class type
            if isinstance(self.policy, partial):
                test_policy = self.policy.func
            else:
                test_policy = self.policy
            assert issubclass(test_policy, DQNPolicy), "Error: the input policy for the DQN model must be " \
                                                       "an instance of DQNPolicy."

            self.graph = tf.Graph()
            with self.graph.as_default():
                self.set_random_seed(self.seed)
                self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess,
                                                 graph=self.graph)

                optimizer = tf.train.AdamOptimizer(
                    learning_rate=self.learning_rate)

                self.act, self._train_step, self.update_target, self.step_model = build_train(
                    q_func=partial(self.policy, **self.policy_kwargs),
                    ob_space=self.observation_space,
                    ac_space=self.action_space,
                    optimizer=optimizer,
                    gamma=self.gamma,
                    grad_norm_clipping=10,
                    param_noise=self.param_noise,
                    sess=self.sess,
                    full_tensorboard_log=self.full_tensorboard_log,
                    double_q=self.double_q)
                self.proba_step = self.step_model.proba_step
                self.params = tf_util.get_trainable_vars("deepq")

                # Initialize the parameters and copy them to the target network.
                tf_util.initialize(self.sess)
                self.update_target(sess=self.sess)

                self.summary = tf.summary.merge_all()
Exemplo n.º 2
0
    def setup_model(self):
        with SetVerbosity(self.verbose):

            assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the A2C model must be an " \
                                                                "instance of common.policies.ActorCriticPolicy."

            self.graph = tf.Graph()
            with self.graph.as_default():
                self.set_random_seed(self.seed)
                self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess,
                                                 graph=self.graph)

                self.n_batch = self.n_envs * self.n_steps

                n_batch_step = None
                n_batch_train = None
                if issubclass(self.policy, RecurrentActorCriticPolicy):
                    n_batch_step = self.n_envs
                    n_batch_train = self.n_envs * self.n_steps

                step_model = self.policy(self.sess,
                                         self.observation_space,
                                         self.action_space,
                                         self.n_envs,
                                         1,
                                         n_batch_step,
                                         reuse=False,
                                         **self.policy_kwargs)

                with tf.variable_scope(
                        "train_model",
                        reuse=True,
                        custom_getter=tf_util.outer_scope_getter(
                            "train_model")):
                    train_model = self.policy(self.sess,
                                              self.observation_space,
                                              self.action_space,
                                              self.n_envs,
                                              self.n_steps,
                                              n_batch_train,
                                              reuse=True,
                                              **self.policy_kwargs)

                with tf.variable_scope("loss", reuse=False):
                    self.actions_ph = train_model.pdtype.sample_placeholder(
                        [None], name="action_ph")
                    self.advs_ph = tf.placeholder(tf.float32, [None],
                                                  name="advs_ph")
                    self.rewards_ph = tf.placeholder(tf.float32, [None],
                                                     name="rewards_ph")
                    self.learning_rate_ph = tf.placeholder(
                        tf.float32, [], name="learning_rate_ph")

                    neglogpac = train_model.proba_distribution.neglogp(
                        self.actions_ph)
                    self.entropy = tf.reduce_mean(
                        train_model.proba_distribution.entropy())
                    self.pg_loss = tf.reduce_mean(self.advs_ph * neglogpac)
                    self.vf_loss = mse(tf.squeeze(train_model.value_flat),
                                       self.rewards_ph)
                    # https://arxiv.org/pdf/1708.04782.pdf#page=9, https://arxiv.org/pdf/1602.01783.pdf#page=4
                    # and https://github.com/dennybritz/reinforcement-learning/issues/34
                    # suggest to add an entropy component in order to improve exploration.
                    loss = self.pg_loss - self.entropy * self.ent_coef + self.vf_loss * self.vf_coef

                    tf.summary.scalar('entropy_loss', self.entropy)
                    tf.summary.scalar('policy_gradient_loss', self.pg_loss)
                    tf.summary.scalar('value_function_loss', self.vf_loss)
                    tf.summary.scalar('loss', loss)

                    self.params = tf_util.get_trainable_vars("model")
                    grads = tf.gradients(loss, self.params)
                    if self.max_grad_norm is not None:
                        grads, _ = tf.clip_by_global_norm(
                            grads, self.max_grad_norm)
                    grads = list(zip(grads, self.params))

                with tf.variable_scope("input_info", reuse=False):
                    tf.summary.scalar('discounted_rewards',
                                      tf.reduce_mean(self.rewards_ph))
                    tf.summary.scalar('learning_rate',
                                      tf.reduce_mean(self.learning_rate_ph))
                    tf.summary.scalar('advantage',
                                      tf.reduce_mean(self.advs_ph))
                    if self.full_tensorboard_log:
                        tf.summary.histogram('discounted_rewards',
                                             self.rewards_ph)
                        tf.summary.histogram('learning_rate',
                                             self.learning_rate_ph)
                        tf.summary.histogram('advantage', self.advs_ph)
                        if tf_util.is_image(self.observation_space):
                            tf.summary.image('observation', train_model.obs_ph)
                        else:
                            tf.summary.histogram('observation',
                                                 train_model.obs_ph)

                trainer = tf.train.RMSPropOptimizer(
                    learning_rate=self.learning_rate_ph,
                    decay=self.alpha,
                    epsilon=self.epsilon,
                    momentum=self.momentum)
                self.apply_backprop = trainer.apply_gradients(grads)

                self.train_model = train_model
                self.step_model = step_model
                self.step = step_model.step
                self.proba_step = step_model.proba_step
                self.value = step_model.value
                self.initial_state = step_model.initial_state
                tf.global_variables_initializer().run(session=self.sess)

                self.summary = tf.summary.merge_all()
Exemplo n.º 3
0
    def setup_model(self):
        with SetVerbosity(self.verbose):

            assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the ACKTR model must be " \
                                                               "an instance of common.policies.ActorCriticPolicy."

            # Enable continuous actions tricks (normalized advantage)
            self.continuous_actions = isinstance(self.action_space, Box)

            self.graph = tf.Graph()
            with self.graph.as_default():
                self.set_random_seed(self.seed)
                self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess,
                                                 graph=self.graph)

                n_batch_step = None
                n_batch_train = None
                if issubclass(self.policy, RecurrentActorCriticPolicy):
                    n_batch_step = self.n_envs
                    n_batch_train = self.n_envs * self.n_steps

                step_model = self.policy(self.sess,
                                         self.observation_space,
                                         self.action_space,
                                         self.n_envs,
                                         1,
                                         n_batch_step,
                                         reuse=False,
                                         **self.policy_kwargs)

                self.params = params = tf_util.get_trainable_vars("model")

                with tf.variable_scope(
                        "train_model",
                        reuse=True,
                        custom_getter=tf_util.outer_scope_getter(
                            "train_model")):
                    train_model = self.policy(self.sess,
                                              self.observation_space,
                                              self.action_space,
                                              self.n_envs,
                                              self.n_steps,
                                              n_batch_train,
                                              reuse=True,
                                              **self.policy_kwargs)

                with tf.variable_scope(
                        "loss",
                        reuse=False,
                        custom_getter=tf_util.outer_scope_getter("loss")):
                    self.advs_ph = advs_ph = tf.placeholder(tf.float32, [None])
                    self.rewards_ph = rewards_ph = tf.placeholder(
                        tf.float32, [None])
                    self.learning_rate_ph = learning_rate_ph = tf.placeholder(
                        tf.float32, [])
                    self.actions_ph = train_model.pdtype.sample_placeholder(
                        [None])

                    neg_log_prob = train_model.proba_distribution.neglogp(
                        self.actions_ph)

                    # training loss
                    pg_loss = tf.reduce_mean(advs_ph * neg_log_prob)
                    self.entropy = entropy = tf.reduce_mean(
                        train_model.proba_distribution.entropy())
                    self.pg_loss = pg_loss = pg_loss - self.ent_coef * entropy
                    self.vf_loss = vf_loss = mse(
                        tf.squeeze(train_model.value_fn), rewards_ph)
                    train_loss = pg_loss + self.vf_coef * vf_loss

                    # Fisher loss construction
                    self.pg_fisher = pg_fisher_loss = -tf.reduce_mean(
                        neg_log_prob)
                    sample_net = train_model.value_fn + tf.random_normal(
                        tf.shape(train_model.value_fn))
                    self.vf_fisher = vf_fisher_loss = -self.vf_fisher_coef * tf.reduce_mean(
                        tf.pow(
                            train_model.value_fn -
                            tf.stop_gradient(sample_net), 2))
                    self.joint_fisher = pg_fisher_loss + vf_fisher_loss

                    tf.summary.scalar('entropy_loss', self.entropy)
                    tf.summary.scalar('policy_gradient_loss', pg_loss)
                    tf.summary.scalar('policy_gradient_fisher_loss',
                                      pg_fisher_loss)
                    tf.summary.scalar('value_function_loss', self.vf_loss)
                    tf.summary.scalar('value_function_fisher_loss',
                                      vf_fisher_loss)
                    tf.summary.scalar('loss', train_loss)

                    self.grads_check = tf.gradients(train_loss, params)

                with tf.variable_scope("input_info", reuse=False):
                    tf.summary.scalar('discounted_rewards',
                                      tf.reduce_mean(self.rewards_ph))
                    tf.summary.scalar('learning_rate',
                                      tf.reduce_mean(self.learning_rate_ph))
                    tf.summary.scalar('advantage',
                                      tf.reduce_mean(self.advs_ph))

                    if self.full_tensorboard_log:
                        tf.summary.histogram('discounted_rewards',
                                             self.rewards_ph)
                        tf.summary.histogram('learning_rate',
                                             self.learning_rate_ph)
                        tf.summary.histogram('advantage', self.advs_ph)
                        if tf_util.is_image(self.observation_space):
                            tf.summary.image('observation', train_model.obs_ph)
                        else:
                            tf.summary.histogram('observation',
                                                 train_model.obs_ph)

                with tf.variable_scope(
                        "kfac",
                        reuse=False,
                        custom_getter=tf_util.outer_scope_getter("kfac")):
                    with tf.device('/gpu:0'):
                        self.optim = optim = kfac.KfacOptimizer(
                            learning_rate=learning_rate_ph,
                            clip_kl=self.kfac_clip,
                            momentum=0.9,
                            kfac_update=self.kfac_update,
                            epsilon=0.01,
                            stats_decay=0.99,
                            async_eigen_decomp=self.async_eigen_decomp,
                            cold_iter=10,
                            max_grad_norm=self.max_grad_norm,
                            verbose=self.verbose)

                        optim.compute_and_apply_stats(self.joint_fisher,
                                                      var_list=params)

                self.train_model = train_model
                self.step_model = step_model
                self.step = step_model.step
                self.proba_step = step_model.proba_step
                self.value = step_model.value
                self.initial_state = step_model.initial_state
                tf.global_variables_initializer().run(session=self.sess)

                self.summary = tf.summary.merge_all()
Exemplo n.º 4
0
    def setup_model(self):
        with SetVerbosity(self.verbose):

            assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the PPO2 model must be " \
                                                               "an instance of common.policies.ActorCriticPolicy."

            self.n_batch = self.n_envs * self.n_steps

            self.graph = tf.Graph()
            with self.graph.as_default():
                self.set_random_seed(self.seed)
                self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess,
                                                 graph=self.graph)

                n_batch_step = None
                n_batch_train = None
                if issubclass(self.policy, RecurrentActorCriticPolicy):
                    assert self.n_envs % self.nminibatches == 0, "For recurrent policies, "\
                        "the number of environments run in parallel should be a multiple of nminibatches."
                    n_batch_step = self.n_envs
                    n_batch_train = self.n_batch // self.nminibatches

                act_model = self.policy(self.sess,
                                        self.observation_space,
                                        self.action_space,
                                        self.n_envs,
                                        1,
                                        n_batch_step,
                                        reuse=False,
                                        **self.policy_kwargs)
                with tf.variable_scope(
                        "train_model",
                        reuse=True,
                        custom_getter=tf_util.outer_scope_getter(
                            "train_model")):
                    train_model = self.policy(self.sess,
                                              self.observation_space,
                                              self.action_space,
                                              self.n_envs // self.nminibatches,
                                              self.n_steps,
                                              n_batch_train,
                                              reuse=True,
                                              **self.policy_kwargs)

                with tf.variable_scope("loss", reuse=False):
                    self.action_ph = train_model.pdtype.sample_placeholder(
                        [None], name="action_ph")
                    self.advs_ph = tf.placeholder(tf.float32, [None],
                                                  name="advs_ph")
                    self.rewards_ph = tf.placeholder(tf.float32, [None],
                                                     name="rewards_ph")
                    self.old_neglog_pac_ph = tf.placeholder(
                        tf.float32, [None], name="old_neglog_pac_ph")
                    self.old_vpred_ph = tf.placeholder(tf.float32, [None],
                                                       name="old_vpred_ph")
                    self.learning_rate_ph = tf.placeholder(
                        tf.float32, [], name="learning_rate_ph")
                    self.clip_range_ph = tf.placeholder(tf.float32, [],
                                                        name="clip_range_ph")

                    neglogpac = train_model.proba_distribution.neglogp(
                        self.action_ph)
                    self.entropy = tf.reduce_mean(
                        train_model.proba_distribution.entropy())

                    vpred = train_model.value_flat

                    # Value function clipping: not present in the original PPO
                    if self.cliprange_vf is None:
                        # Default behavior (legacy from OpenAI baselines):
                        # use the same clipping as for the policy
                        self.clip_range_vf_ph = self.clip_range_ph
                        self.cliprange_vf = self.cliprange
                    elif isinstance(self.cliprange_vf,
                                    (float, int)) and self.cliprange_vf < 0:
                        # Original PPO implementation: no value function clipping
                        self.clip_range_vf_ph = None
                    else:
                        # Last possible behavior: clipping range
                        # specific to the value function
                        self.clip_range_vf_ph = tf.placeholder(
                            tf.float32, [], name="clip_range_vf_ph")

                    if self.clip_range_vf_ph is None:
                        # No clipping
                        vpred_clipped = train_model.value_flat
                    else:
                        # Clip the different between old and new value
                        # NOTE: this depends on the reward scaling
                        vpred_clipped = self.old_vpred_ph + \
                            tf.clip_by_value(train_model.value_flat - self.old_vpred_ph,
                                             - self.clip_range_vf_ph, self.clip_range_vf_ph)

                    vf_losses1 = tf.square(vpred - self.rewards_ph)
                    vf_losses2 = tf.square(vpred_clipped - self.rewards_ph)
                    self.vf_loss = .5 * tf.reduce_mean(
                        tf.maximum(vf_losses1, vf_losses2))

                    ratio = tf.exp(self.old_neglog_pac_ph - neglogpac)
                    pg_losses = -self.advs_ph * ratio
                    pg_losses2 = -self.advs_ph * tf.clip_by_value(
                        ratio, 1.0 - self.clip_range_ph,
                        1.0 + self.clip_range_ph)
                    self.pg_loss = tf.reduce_mean(
                        tf.maximum(pg_losses, pg_losses2))
                    self.approxkl = .5 * tf.reduce_mean(
                        tf.square(neglogpac - self.old_neglog_pac_ph))
                    self.clipfrac = tf.reduce_mean(
                        tf.cast(
                            tf.greater(tf.abs(ratio - 1.0),
                                       self.clip_range_ph), tf.float32))
                    loss = self.pg_loss - self.entropy * self.ent_coef + self.vf_loss * self.vf_coef

                    tf.summary.scalar('entropy_loss', self.entropy)
                    tf.summary.scalar('policy_gradient_loss', self.pg_loss)
                    tf.summary.scalar('value_function_loss', self.vf_loss)
                    tf.summary.scalar('approximate_kullback-leibler',
                                      self.approxkl)
                    tf.summary.scalar('clip_factor', self.clipfrac)
                    tf.summary.scalar('loss', loss)

                    with tf.variable_scope('model'):
                        self.params = tf.trainable_variables()
                        if self.full_tensorboard_log:
                            for var in self.params:
                                tf.summary.histogram(var.name, var)
                    grads = tf.gradients(loss, self.params)
                    if self.max_grad_norm is not None:
                        grads, _grad_norm = tf.clip_by_global_norm(
                            grads, self.max_grad_norm)
                    grads = list(zip(grads, self.params))
                trainer = tf.train.AdamOptimizer(
                    learning_rate=self.learning_rate_ph, epsilon=1e-5)
                self._train = trainer.apply_gradients(grads)

                self.loss_names = [
                    'policy_loss', 'value_loss', 'policy_entropy', 'approxkl',
                    'clipfrac'
                ]

                with tf.variable_scope("input_info", reuse=False):
                    tf.summary.scalar('discounted_rewards',
                                      tf.reduce_mean(self.rewards_ph))
                    tf.summary.scalar('learning_rate',
                                      tf.reduce_mean(self.learning_rate_ph))
                    tf.summary.scalar('advantage',
                                      tf.reduce_mean(self.advs_ph))
                    tf.summary.scalar('clip_range',
                                      tf.reduce_mean(self.clip_range_ph))
                    if self.clip_range_vf_ph is not None:
                        tf.summary.scalar(
                            'clip_range_vf',
                            tf.reduce_mean(self.clip_range_vf_ph))

                    tf.summary.scalar('old_neglog_action_probability',
                                      tf.reduce_mean(self.old_neglog_pac_ph))
                    tf.summary.scalar('old_value_pred',
                                      tf.reduce_mean(self.old_vpred_ph))

                    if self.full_tensorboard_log:
                        tf.summary.histogram('discounted_rewards',
                                             self.rewards_ph)
                        tf.summary.histogram('learning_rate',
                                             self.learning_rate_ph)
                        tf.summary.histogram('advantage', self.advs_ph)
                        tf.summary.histogram('clip_range', self.clip_range_ph)
                        tf.summary.histogram('old_neglog_action_probability',
                                             self.old_neglog_pac_ph)
                        tf.summary.histogram('old_value_pred',
                                             self.old_vpred_ph)
                        if tf_util.is_image(self.observation_space):
                            tf.summary.image('observation', train_model.obs_ph)
                        else:
                            tf.summary.histogram('observation',
                                                 train_model.obs_ph)

                self.train_model = train_model
                self.act_model = act_model
                self.step = act_model.step
                self.proba_step = act_model.proba_step
                self.value = act_model.value
                self.initial_state = act_model.initial_state
                tf.global_variables_initializer().run(session=self.sess)  # pylint: disable=E1101

                self.summary = tf.summary.merge_all()
Exemplo n.º 5
0
    def setup_model(self):
        with SetVerbosity(self.verbose):

            assert issubclass(self.policy, ActorCriticPolicy), "Error: the input policy for the ACER model must be " \
                                                               "an instance of common.policies.ActorCriticPolicy."

            if isinstance(self.action_space, Discrete):
                self.n_act = self.action_space.n
                continuous = False
            elif isinstance(self.action_space, Box):
                # self.n_act = self.action_space.shape[-1]
                # continuous = True
                raise NotImplementedError("WIP: Acer does not support Continuous actions yet.")
            else:
                raise ValueError("Error: ACER does not work with {} actions space.".format(self.action_space))

            self.n_batch = self.n_envs * self.n_steps

            self.graph = tf.Graph()
            with self.graph.as_default():
                self.sess = tf_util.make_session(num_cpu=self.n_cpu_tf_sess, graph=self.graph)
                self.set_random_seed(self.seed)
                n_batch_step = None
                if issubclass(self.policy, RecurrentActorCriticPolicy):
                    n_batch_step = self.n_envs
                n_batch_train = self.n_envs * (self.n_steps + 1)

                step_model = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs, 1,
                                         n_batch_step, reuse=False, **self.policy_kwargs)

                self.params = tf_util.get_trainable_vars("model")

                with tf.variable_scope("train_model", reuse=True,
                                       custom_getter=tf_util.outer_scope_getter("train_model")):
                    train_model = self.policy(self.sess, self.observation_space, self.action_space, self.n_envs,
                                              self.n_steps + 1, n_batch_train, reuse=True, **self.policy_kwargs)

                with tf.variable_scope("moving_average"):
                    # create averaged model
                    ema = tf.train.ExponentialMovingAverage(self.alpha)
                    ema_apply_op = ema.apply(self.params)

                    def custom_getter(getter, name, *args, **kwargs):
                        name = name.replace("polyak_model/", "")
                        val = ema.average(getter(name, *args, **kwargs))
                        return val

                with tf.variable_scope("polyak_model", reuse=True, custom_getter=custom_getter):
                    self.polyak_model = polyak_model = self.policy(self.sess, self.observation_space, self.action_space,
                                                                   self.n_envs, self.n_steps + 1,
                                                                   self.n_envs * (self.n_steps + 1), reuse=True,
                                                                   **self.policy_kwargs)

                with tf.variable_scope("loss", reuse=False):
                    self.done_ph = tf.placeholder(tf.float32, [self.n_batch])  # dones
                    self.reward_ph = tf.placeholder(tf.float32, [self.n_batch])  # rewards, not returns
                    self.mu_ph = tf.placeholder(tf.float32, [self.n_batch, self.n_act])  # mu's
                    self.action_ph = train_model.pdtype.sample_placeholder([self.n_batch])
                    self.learning_rate_ph = tf.placeholder(tf.float32, [])
                    eps = 1e-6

                    # Notation: (var) = batch variable, (var)s = sequence variable,
                    # (var)_i = variable index by action at step i
                    # shape is [n_envs * (n_steps + 1)]
                    if continuous:
                        value = train_model.value_flat
                    else:
                        value = tf.reduce_sum(train_model.policy_proba * train_model.q_value, axis=-1)

                    rho, rho_i_ = None, None
                    if continuous:
                        action_ = strip(train_model.proba_distribution.sample(), self.n_envs, self.n_steps)
                        distribution_f = tf.contrib.distributions.MultivariateNormalDiag(
                            loc=strip(train_model.proba_distribution.mean, self.n_envs, self.n_steps),
                            scale_diag=strip(train_model.proba_distribution.logstd, self.n_envs, self.n_steps))
                        f_polyak = tf.contrib.distributions.MultivariateNormalDiag(
                            loc=strip(polyak_model.proba_distribution.mean, self.n_envs, self.n_steps),
                            scale_diag=strip(polyak_model.proba_distribution.logstd, self.n_envs, self.n_steps))

                        f_i = distribution_f.prob(self.action_ph)
                        f_i_ = distribution_f.prob(action_)
                        f_polyak_i = f_polyak.prob(self.action_ph)
                        phi_i = strip(train_model.proba_distribution.mean, self.n_envs, self.n_steps)

                        q_value = strip(train_model.value_fn, self.n_envs, self.n_steps)
                        q_i = q_value[:, 0]

                        rho_i = tf.reshape(f_i, [-1, 1]) / (self.mu_ph + eps)
                        rho_i_ = tf.reshape(f_i_, [-1, 1]) / (self.mu_ph + eps)

                        qret = q_retrace(self.reward_ph, self.done_ph, q_i, value, tf.pow(rho_i, 1 / self.n_act),
                                         self.n_envs, self.n_steps, self.gamma)
                    else:
                        # strip off last step
                        # f is a distribution, chosen to be Gaussian distributions
                        # with fixed diagonal covariance and mean \phi(x)
                        # in the paper
                        distribution_f, f_polyak, q_value = \
                            map(lambda variables: strip(variables, self.n_envs, self.n_steps),
                                [train_model.policy_proba, polyak_model.policy_proba, train_model.q_value])

                        # Get pi and q values for actions taken
                        f_i = get_by_index(distribution_f, self.action_ph)
                        f_i_ = distribution_f
                        phi_i = distribution_f
                        f_polyak_i = f_polyak

                        q_i = get_by_index(q_value, self.action_ph)

                        # Compute ratios for importance truncation
                        rho = distribution_f / (self.mu_ph + eps)
                        rho_i = get_by_index(rho, self.action_ph)

                        # Calculate Q_retrace targets
                        qret = q_retrace(self.reward_ph, self.done_ph, q_i, value, rho_i, self.n_envs, self.n_steps,
                                         self.gamma)

                    # Calculate losses
                    # Entropy
                    entropy = tf.reduce_sum(train_model.proba_distribution.entropy())

                    # Policy Gradient loss, with truncated importance sampling & bias correction
                    value = strip(value, self.n_envs, self.n_steps, True)
                    # check_shape([qret, value, rho_i, f_i], [[self.n_envs * self.n_steps]] * 4)
                    # check_shape([rho, distribution_f, q_value], [[self.n_envs * self.n_steps, self.n_act]] * 2)

                    # Truncated importance sampling
                    adv = qret - value
                    log_f = tf.log(f_i + eps)
                    # [n_envs * n_steps]
                    gain_f = log_f * tf.stop_gradient(adv * tf.minimum(self.correction_term, rho_i))
                    loss_f = -tf.reduce_mean(gain_f)

                    # Bias correction for the truncation
                    adv_bc = (q_value - tf.reshape(value, [self.n_envs * self.n_steps, 1]))  # [n_envs * n_steps, n_act]

                    # check_shape([adv_bc, log_f_bc], [[self.n_envs * self.n_steps, self.n_act]] * 2)
                    if continuous:
                        gain_bc = tf.stop_gradient(adv_bc *
                                                   tf.nn.relu(1.0 - (self.correction_term / (rho_i_ + eps))) *
                                                   f_i_)
                    else:
                        log_f_bc = tf.log(f_i_ + eps)  # / (f_old + eps)
                        gain_bc = tf.reduce_sum(log_f_bc *
                                                tf.stop_gradient(
                                                    adv_bc *
                                                    tf.nn.relu(1.0 - (self.correction_term / (rho + eps))) *
                                                    f_i_),
                                                axis=1)
                    # IMP: This is sum, as expectation wrt f
                    loss_bc = -tf.reduce_mean(gain_bc)

                    loss_policy = loss_f + loss_bc

                    # Value/Q function loss, and explained variance
                    check_shape([qret, q_i], [[self.n_envs * self.n_steps]] * 2)
                    explained_variance = q_explained_variance(tf.reshape(q_i, [self.n_envs, self.n_steps]),
                                                              tf.reshape(qret, [self.n_envs, self.n_steps]))
                    loss_q = tf.reduce_mean(tf.square(tf.stop_gradient(qret) - q_i) * 0.5)

                    # Net loss
                    check_shape([loss_policy, loss_q, entropy], [[]] * 3)
                    loss = loss_policy + self.q_coef * loss_q - self.ent_coef * entropy

                    tf.summary.scalar('entropy_loss', entropy)
                    tf.summary.scalar('policy_gradient_loss', loss_policy)
                    tf.summary.scalar('value_function_loss', loss_q)
                    tf.summary.scalar('loss', loss)

                    norm_grads_q, norm_grads_policy, avg_norm_grads_f = None, None, None
                    avg_norm_k, avg_norm_g, avg_norm_k_dot_g, avg_norm_adj = None, None, None, None
                    if self.trust_region:
                        # [n_envs * n_steps, n_act]
                        grad = tf.gradients(- (loss_policy - self.ent_coef * entropy) * self.n_steps * self.n_envs,
                                            phi_i)
                        # [n_envs * n_steps, n_act] # Directly computed gradient of KL divergence wrt f
                        kl_grad = - f_polyak_i / (f_i_ + eps)
                        k_dot_g = tf.reduce_sum(kl_grad * grad, axis=-1)
                        adj = tf.maximum(0.0, (tf.reduce_sum(kl_grad * grad, axis=-1) - self.delta) / (
                                tf.reduce_sum(tf.square(kl_grad), axis=-1) + eps))  # [n_envs * n_steps]

                        # Calculate stats (before doing adjustment) for logging.
                        avg_norm_k = avg_norm(kl_grad)
                        avg_norm_g = avg_norm(grad)
                        avg_norm_k_dot_g = tf.reduce_mean(tf.abs(k_dot_g))
                        avg_norm_adj = tf.reduce_mean(tf.abs(adj))

                        grad = grad - tf.reshape(adj, [self.n_envs * self.n_steps, 1]) * kl_grad
                        # These are turst region adjusted gradients wrt f ie statistics of policy pi
                        grads_f = -grad / (self.n_envs * self.n_steps)
                        grads_policy = tf.gradients(f_i_, self.params, grads_f)
                        grads_q = tf.gradients(loss_q * self.q_coef, self.params)
                        grads = [gradient_add(g1, g2, param, verbose=self.verbose)
                                 for (g1, g2, param) in zip(grads_policy, grads_q, self.params)]

                        avg_norm_grads_f = avg_norm(grads_f) * (self.n_steps * self.n_envs)
                        norm_grads_q = tf.global_norm(grads_q)
                        norm_grads_policy = tf.global_norm(grads_policy)
                    else:
                        grads = tf.gradients(loss, self.params)

                    norm_grads = None
                    if self.max_grad_norm is not None:
                        grads, norm_grads = tf.clip_by_global_norm(grads, self.max_grad_norm)
                    grads = list(zip(grads, self.params))

                with tf.variable_scope("input_info", reuse=False):
                    tf.summary.scalar('rewards', tf.reduce_mean(self.reward_ph))
                    tf.summary.scalar('learning_rate', tf.reduce_mean(self.learning_rate))
                    tf.summary.scalar('advantage', tf.reduce_mean(adv))
                    tf.summary.scalar('action_probability', tf.reduce_mean(self.mu_ph))

                    if self.full_tensorboard_log:
                        tf.summary.histogram('rewards', self.reward_ph)
                        tf.summary.histogram('learning_rate', self.learning_rate)
                        tf.summary.histogram('advantage', adv)
                        tf.summary.histogram('action_probability', self.mu_ph)
                        if tf_util.is_image(self.observation_space):
                            tf.summary.image('observation', train_model.obs_ph)
                        else:
                            tf.summary.histogram('observation', train_model.obs_ph)

                trainer = tf.train.RMSPropOptimizer(learning_rate=self.learning_rate_ph, decay=self.rprop_alpha,
                                                    epsilon=self.rprop_epsilon)
                _opt_op = trainer.apply_gradients(grads)

                # so when you call _train, you first do the gradient step, then you apply ema
                with tf.control_dependencies([_opt_op]):
                    _train = tf.group(ema_apply_op)

                # Ops/Summaries to run, and their names for logging
                assert norm_grads is not None
                run_ops = [_train, loss, loss_q, entropy, loss_policy, loss_f, loss_bc, explained_variance, norm_grads]
                names_ops = ['loss', 'loss_q', 'entropy', 'loss_policy', 'loss_f', 'loss_bc', 'explained_variance',
                             'norm_grads']
                if self.trust_region:
                    self.run_ops = run_ops + [norm_grads_q, norm_grads_policy, avg_norm_grads_f, avg_norm_k, avg_norm_g,
                                              avg_norm_k_dot_g, avg_norm_adj]
                    self.names_ops = names_ops + ['norm_grads_q', 'norm_grads_policy', 'avg_norm_grads_f', 'avg_norm_k',
                                                  'avg_norm_g', 'avg_norm_k_dot_g', 'avg_norm_adj']

                self.train_model = train_model
                self.step_model = step_model
                self.step = step_model.step
                self.proba_step = step_model.proba_step
                self.initial_state = step_model.initial_state

                tf.global_variables_initializer().run(session=self.sess)

                self.summary = tf.summary.merge_all()