def end_epoch(self):
        """
        Finally arrived at the end of epoch (full pass on dataset).
        Do some tensorboard logging and checkpoint saving.
        """
        logger.info(f"{self.n_sequences_epoch} sequences have been trained during this epoch.")

        if self.is_master:
            self.save_checkpoint(checkpoint_name=f"model_epoch_{self.epoch}.pth")
            self.tensorboard.add_scalar(
                tag="epoch/loss", scalar_value=self.total_loss_epoch / self.n_iter, global_step=self.epoch
            )

        self.epoch += 1
        self.n_sequences_epoch = 0
        self.n_iter = 0
        self.total_loss_epoch = 0 

def __init__(self, args):
		super(CEMLearner, self).__init__(args)

		policy_conf = {'name': 'local_learning_{}'.format(self.actor_id),
					   'input_shape': self.input_shape,
					   'num_act': self.num_actions,
					   'args': args}

		self.local_network = args.network(policy_conf)
		self.num_params = np.sum([
			np.prod(v.get_shape().as_list())
			for v in self.local_network.params])

		logger.info('Parameter count: {}'.format(self.num_params))
		self.mu = np.zeros(self.num_params)
		self.sigma = np.ones(self.num_params)
		self.num_samples = args.episodes_per_batch
		self.num_epochs = args.num_epochs

		if self.is_master():
			var_list = self.local_network.params
			self.saver = tf.train.Saver(var_list=var_list, max_to_keep=3,
                                        keep_checkpoint_every_n_hours=2) 

def _add_archives(self, collection):
        logger.info("%s " % "article", False)
        result = ""
        archives = list(collection.find({}))
        page_count = len(archives) / 10 + 1
        result += self._add_one(
                "archives",
                datetime.now()
            )
        for index in xrange(page_count):
            result += self._add_one(
                "%s/%d" % ("archives", index),
                datetime.now()
            )
        for article in archives:
            result += self._add_one(
                "%s/%s" % ("article", article["slug"]),
                datetime.strptime(article["date"], "%Y.%m.%d %H:%M")
            )
        return result 

def generate(self):
        logger.info("Sitemap: Writing start...")
        with open(config["sitemap_path"], "w") as f:
            f.write(template["begin"])
            f.write(self._add_static())
            logger.info("Sitemap: Writing: ")
            for url in ["tag", "author", "category"]:
                f.write(
                    self._add_collection(url, self._collections[url])
                )
            f.write(
                self._add_archives(self._collections["article"])
            )
            f.write(template["end"])
            f.close()
        logger.info("Sitemap: Writing done...") 

def _update_files(self, file_names, time):
        if not os.path.exists(config["feeds_dir_path"]):
            os.mkdir(config["feeds_dir_path"])
        for name_pair in file_names:
            name, view = name_pair["slug"].encode("utf-8"), name_pair["view"].encode("utf-8")
            if name not in self._files:
                file_name = "%s/%s.rss.xml" % (
                    config["feeds_dir_path"],
                    name
                    )
                self._files[name] = open(file_name, "w")
                self._files[name].write(
                    template["begin"].format(
                        config["site_title"],
                        config["site_url"],
                        config["site_description"],
                        "%s/%s" % (
                            config["site_url"],
                            file_name
                        ),
                        time
                    )
                )
                logger.info("'%s' " % view, False) 

def write(self, file_path, mode="delete", page=None):
        logger.info("Writing start: %s" % file_path)

        self._file_path = file_path
        if mode != "delete" and page == None:
            self._error("Mode is not 'delete', argument 'page' is required !")
        if mode == "update":
            if self._articles.find_one(
                {
                    "file": file_path
                }
            ):
                self._update(file_path, page)
            else:
                self._insert(page)
        elif mode == "delete":
            self._delete(file_path)
        else:
            self._error("Unexpected mode '%s' !" % mode) 

def __init__(self, name, is_train, norm='instance', activation='leaky',
                 image_size=128, latent_dim=8, use_resnet=True):
        logger.info('Init Encoder %s', name)
        self.name = name
        self._is_train = is_train
        self._norm = norm
        self._activation = activation
        self._reuse = False
        self._image_size = image_size
        self._latent_dim = latent_dim
        self._use_resnet = use_resnet 

def __init__(self, name, is_train, norm='instance', activation='leaky', image_size=128):
        logger.info('Init Discriminator %s', name)
        self.name = name
        self._is_train = is_train
        self._norm = norm
        self._activation = activation
        self._reuse = False
        self._image_size = image_size 

def __init__(self, name, is_train, norm='batch', image_size=128):
        logger.info('Init Generator %s', name)
        self.name = name
        self._is_train = is_train
        self._norm = norm
        self._reuse = False
        self._image_size = image_size 

def __init__(self, name, is_train, norm='instance', activation='leaky'):
        logger.info('Init Discriminator %s', name)
        self.name = name
        self._is_train = is_train
        self._norm = norm
        self._activation = activation
        self._reuse = False 

def __init__(self, name, is_train, norm='instance', activation='relu',
                 image_size=128):
        logger.info('Init Generator %s', name)
        self.name = name
        self._is_train = is_train
        self._norm = norm
        self._activation = activation
        self._num_res_block = 6 if image_size == 128 else 9
        self._reuse = False 

def remove_long_sequences(self):
        """
        Sequences that are too long are splitted by chunk of max_model_input_size.
        """
        max_len = self.params.max_model_input_size
        indices = self.lengths > max_len
        logger.info(f"Splitting {sum(indices)} too long sequences.")

        def divide_chunks(l, n):
            return [l[i : i + n] for i in range(0, len(l), n)]

        new_tok_ids = []
        new_lengths = []
        if self.params.mlm:
            cls_id, sep_id = self.params.special_tok_ids["cls_token"], self.params.special_tok_ids["sep_token"]
        else:
            cls_id, sep_id = self.params.special_tok_ids["bos_token"], self.params.special_tok_ids["eos_token"]

        for seq_, len_ in zip(self.token_ids, self.lengths):
            assert (seq_[0] == cls_id) and (seq_[-1] == sep_id), seq_
            if len_ <= max_len:
                new_tok_ids.append(seq_)
                new_lengths.append(len_)
            else:
                sub_seqs = []
                for sub_s in divide_chunks(seq_, max_len - 2):
                    if sub_s[0] != cls_id:
                        sub_s = np.insert(sub_s, 0, cls_id)
                    if sub_s[-1] != sep_id:
                        sub_s = np.insert(sub_s, len(sub_s), sep_id)
                    assert len(sub_s) <= max_len
                    assert (sub_s[0] == cls_id) and (sub_s[-1] == sep_id), sub_s
                    sub_seqs.append(sub_s)

                new_tok_ids.extend(sub_seqs)
                new_lengths.extend([len(l) for l in sub_seqs])

        self.token_ids = np.array(new_tok_ids)
        self.lengths = np.array(new_lengths) 

def remove_empty_sequences(self):
        """
        Too short sequences are simply removed. This could be tunedd.
        """
        init_size = len(self)
        indices = self.lengths > 11
        self.token_ids = self.token_ids[indices]
        self.lengths = self.lengths[indices]
        new_size = len(self)
        logger.info(f"Remove {init_size - new_size} too short (<=11 tokens) sequences.") 

def remove_unknown_sequences(self):
        """
        Remove sequences with a (too) high level of unknown tokens.
        """
        if "unk_token" not in self.params.special_tok_ids:
            return
        else:
            unk_token_id = self.params.special_tok_ids["unk_token"]
        init_size = len(self)
        unk_occs = np.array([np.count_nonzero(a == unk_token_id) for a in self.token_ids])
        indices = (unk_occs / self.lengths) < 0.5
        self.token_ids = self.token_ids[indices]
        self.lengths = self.lengths[indices]
        new_size = len(self)
        logger.info(f"Remove {init_size - new_size} sequences with a high level of unknown tokens (50%).") 

def print_statistics(self):
        """
        Print some statistics on the corpus. Only the master process.
        """
        if not self.params.is_master:
            return
        logger.info(f"{len(self)} sequences")
        # data_len = sum(self.lengths)
        # nb_unique_tokens = len(Counter(list(chain(*self.token_ids))))
        # logger.info(f'{data_len} tokens ({nb_unique_tokens} unique)')

        # unk_idx = self.params.special_tok_ids['unk_token']
        # nb_unkown = sum([(t==unk_idx).sum() for t in self.token_ids])
        # logger.info(f'{nb_unkown} unknown tokens (covering {100*nb_unkown/data_len:.2f}% of the data)') 

def train(self):
        """
        The real training loop.
        """
        if self.is_master:
            logger.info("Starting training")
        self.last_log = time.time()
        self.student.train()
        self.teacher.eval()

        for _ in range(self.params.n_epoch):
            if self.is_master:
                logger.info(f"--- Starting epoch {self.epoch}/{self.params.n_epoch-1}")
            if self.multi_gpu:
                torch.distributed.barrier()

            iter_bar = tqdm(self.dataloader, desc="-Iter", disable=self.params.local_rank not in [-1, 0])
            for batch in iter_bar:
                if self.params.n_gpu > 0:
                    batch = tuple(t.to(f"cuda:{self.params.local_rank}") for t in batch)

                if self.mlm:
                    token_ids, attn_mask, lm_labels = self.prepare_batch_mlm(batch=batch)
                else:
                    token_ids, attn_mask, lm_labels = self.prepare_batch_clm(batch=batch)
                self.step(input_ids=token_ids, attention_mask=attn_mask, lm_labels=lm_labels)

                iter_bar.update()
                iter_bar.set_postfix(
                    {"Last_loss": f"{self.last_loss:.2f}", "Avg_cum_loss": f"{self.total_loss_epoch/self.n_iter:.2f}"}
                )
            iter_bar.close()

            if self.is_master:
                logger.info(f"--- Ending epoch {self.epoch}/{self.params.n_epoch-1}")
            self.end_epoch()

        if self.is_master:
            logger.info(f"Save very last checkpoint as `pytorch_model.bin`.")
            self.save_checkpoint(checkpoint_name=f"pytorch_model.bin")
            logger.info("Training is finished") 

def create_lengths_groups(lengths, k=0):
    bins = np.arange(start=3, stop=k, step=4).tolist() if k > 0 else [10]
    groups = _quantize(lengths, bins)
    # count number of elements per group
    counts = np.unique(groups, return_counts=True)[1]
    fbins = [0] + bins + [np.inf]
    logger.info("Using {} as bins for aspect lengths quantization".format(fbins))
    logger.info("Count of instances per bin: {}".format(counts))
    return groups 

def remove_long_sequences(self):
        """
        Sequences that are too long are splitted by chunk of max_model_input_size.
        """
        max_len = self.params.max_model_input_size
        indices = self.lengths > max_len
        logger.info(f'Splitting {sum(indices)} too long sequences.')

        def divide_chunks(l, n):
            return [l[i:i + n] for i in range(0, len(l), n)]

        new_tok_ids = []
        new_lengths = []
        if self.params.mlm:
            cls_id, sep_id = self.params.special_tok_ids['cls_token'], self.params.special_tok_ids['sep_token']
        else:
            cls_id, sep_id = self.params.special_tok_ids['bos_token'], self.params.special_tok_ids['eos_token']

        for seq_, len_ in zip(self.token_ids, self.lengths):
            assert (seq_[0] == cls_id) and (seq_[-1] == sep_id), seq_
            if len_ <= max_len:
                new_tok_ids.append(seq_)
                new_lengths.append(len_)
            else:
                sub_seqs = []
                for sub_s in divide_chunks(seq_, max_len-2):
                    if sub_s[0] != cls_id:
                        sub_s = np.insert(sub_s, 0, cls_id)
                    if sub_s[-1] != sep_id:
                        sub_s = np.insert(sub_s, len(sub_s), sep_id)
                    assert len(sub_s) <= max_len
                    assert (sub_s[0] == cls_id) and (sub_s[-1] == sep_id), sub_s
                    sub_seqs.append(sub_s)

                new_tok_ids.extend(sub_seqs)
                new_lengths.extend([len(l) for l in sub_seqs])

        self.token_ids = np.array(new_tok_ids)
        self.lengths = np.array(new_lengths) 

def remove_empty_sequences(self):
        """
        Too short sequences are simply removed. This could be tunedd.
        """
        init_size = len(self)
        indices = self.lengths > 11
        self.token_ids = self.token_ids[indices]
        self.lengths = self.lengths[indices]
        new_size = len(self)
        logger.info(f'Remove {init_size - new_size} too short (<=11 tokens) sequences.') 

def print_statistics(self):
        """
        Print some statistics on the corpus. Only the master process.
        """
        if not self.params.is_master:
            return
        logger.info(f'{len(self)} sequences')
        # data_len = sum(self.lengths)
        # nb_unique_tokens = len(Counter(list(chain(*self.token_ids))))
        # logger.info(f'{data_len} tokens ({nb_unique_tokens} unique)')

        # unk_idx = self.params.special_tok_ids['unk_token']
        # nb_unkown = sum([(t==unk_idx).sum() for t in self.token_ids])
        # logger.info(f'{nb_unkown} unknown tokens (covering {100*nb_unkown/data_len:.2f}% of the data)') 

def train(self):
        """
        The real training loop.
        """
        if self.is_master:
            logger.info("Starting training")
        self.last_log = time.time()
        self.student.train()
        self.teacher.eval()

        for _ in range(self.params.n_epoch):
            if self.is_master:
                logger.info(f"--- Starting epoch {self.epoch}/{self.params.n_epoch-1}")
            if self.multi_gpu:
                torch.distributed.barrier()

            iter_bar = tqdm(self.dataloader, desc="-Iter", disable=self.params.local_rank not in [-1, 0])
            for batch in iter_bar:
                if self.params.n_gpu > 0:
                    batch = tuple(t.to(f"cuda:{self.params.local_rank}") for t in batch)

                if self.mlm:
                    token_ids, attn_mask, lm_labels = self.prepare_batch_mlm(batch=batch)
                else:
                    token_ids, attn_mask, lm_labels = self.prepare_batch_clm(batch=batch)
                self.step(input_ids=token_ids, attention_mask=attn_mask, lm_labels=lm_labels)

                iter_bar.update()
                iter_bar.set_postfix(
                    {"Last_loss": f"{self.last_loss:.2f}", "Avg_cum_loss": f"{self.total_loss_epoch/self.n_iter:.2f}"}
                )
            iter_bar.close()

            if self.is_master:
                logger.info(f"--- Ending epoch {self.epoch}/{self.params.n_epoch-1}")
            self.end_epoch()

        if self.is_master:
            logger.info(f"Save very last checkpoint as `pytorch_model.bin`.")
            self.save_checkpoint(checkpoint_name=f"pytorch_model.bin")
            logger.info("Training is finished") 

def write_density_model(self):
        logger.info('T{} Writing Pickled Density Model to File...'.format(self.actor_id))
        raw_data = cPickle.dumps(self.density_model.get_state(), protocol=2)
        with self.barrier.counter.lock, open('/tmp/density_model.pkl', 'wb') as f:
            f.write(raw_data)

        for i in xrange(len(self.density_model_update_flags.updated)):
            self.density_model_update_flags.updated[i] = 1 

def read_density_model(self):
        logger.info('T{} Synchronizing Density Model...'.format(self.actor_id))
        with self.barrier.counter.lock, open('/tmp/density_model.pkl', 'rb') as f:
            raw_data = f.read()

        self.density_model.set_state(cPickle.loads(raw_data)) 

def test(self, num_episodes=100):
        """
        Run test monitor for `num_episodes`
        """
        rewards = list()
        for episode in range(num_episodes):
            s = self.emulator.get_initial_state()
            self.reset_hidden_state()
            total_episode_reward = 0
            episode_over = False

            while not episode_over:
                a = self.choose_next_action(s)[0]
                s, reward, episode_over = self.emulator.next(a)

                total_episode_reward += reward

            else:
                rewards.append(total_episode_reward)
                logger.info("EPISODE {0} -- REWARD: {1}, RUNNING AVG: {2:.1f}±{3:.1f}, BEST: {4}".format(
                    episode,
                    total_episode_reward,
                    np.array(rewards).mean(),
                    2*np.array(rewards).std(),
                    max(rewards),
                )) 

def _handle(self, parameters=None):
        hasOrigin = "origin" in request.headers
        logger.info("Request: %s\nFrom: %s\nUrl: %s" % (
            self.url,
            request.headers["Referer"] if hasOrigin else request.remote_addr,
            request.url
        ))
        if hasOrigin and (request.headers["origin"] not in config["allow-origin"]):
            return self._403(parameters)
        if not (request.remote_addr in config["allow-ip"]):
            return self._403(parameters)
        params = self._parse_parameters(parameters)

        cache = self._cache

        if cache != None and cache.has(params) and not cache.is_modified(params):
            return self._304(params, cache.get(params))

        data = self._find_data(params)
        if not data:
            return self._404(parameters)

        logger.info("Data found: %s\nParameters: %s" % (
            self.url, parameters
        ))

        if cache != None:
            cache.updateContent(params, data)

        return self._response(
            self._format_data(200, data, self.url, params),
            200
        ) 

def _304(self, parameters, data):
        logger.info("304: %s\nParameters: %s" % (
            self.url, parameters
        ))
        return self._response(
            self._format_data(304, data, self.url, parameters),
            200
        ) 

def _add_collection(self, url, collection):
        logger.info("%s " % url, False)
        result = ""
        for item in list(collection.find({})):
            result += self._add_one(
                    "%s/%s" % (url, item["slug"]),
                    datetime.now()
                )
            for index in xrange(item["count"] / config["articles_per_page"] + 1):
                result += self._add_one(
                    "%s/%s/%d" % (url, item["slug"], index),
                    datetime.now()
                )
        return result 

def wrap(self, metadata):
        logger.info("Wrapping start")
        return self._slug_wrap(metadata) 

def generate(self):
        logger.info("Feeds: Writing start...")
        self._files = {}
        time = format_date(datetime.now(), "feeds")
        articles = list(self._collection.find({}))
        articles.sort(
            key=lambda article: article["date"],reverse=True
        )
        logger.info("Feeds: Writing: ")
        for article in articles:
            content, file_names = self._format_article(article)
            self._update_files(file_names, time)
            for name in file_names:
                self._files[name["slug"].encode("utf-8")].write(
                    self._add_one(content)
                )
        indexes = {}
        logger.info("Feeds: Done: ")
        for file_name, file_obj in self._files.items():
            file_obj.write(
                template["end"]
            )
            file_obj.close()
            indexes[file_name] = "%s.rss.xml" % file_name
            logger.info("'%s' " % file_name, False)
        with open(
            "%s/%s" % (
                        config["feeds_dir_path"],
                    "indexes.json"
                ),
            "w"
        ) as f:
            json.dump(indexes ,f)
        logger.info("Feeds: Writing done...") 

def updateContent(self, parameters, content):
        name = parameters
        logger.info("Cache: %s - %s\nParams: %s" % ("update", self.flag, parameters))
        self._cache[name] = content
        self._state[name] = False