examples/tensorflow/language-modeling/run_clm.py/tokenize_function
def main():
    # region Argument Parsing
    parser = HfArgumentParser((ModelArguments, DataTrainingArguments, TFTrainingArguments))
    if len(sys.argv) == 2 and sys.argv[1].endswith(".json"):
        # If we pass only one argument to the script and it's the path to a json file,
        # let's parse it to get our arguments.
        model_args, data_args, training_args = parser.parse_json_file(json_file=os.path.abspath(sys.argv[1]))
    else:
        model_args, data_args, training_args = parser.parse_args_into_dataclasses()

    # Sending telemetry. Tracking the example usage helps us better allocate resources to maintain them. The
    # information sent is the one passed as arguments along with your Python/PyTorch versions.
    send_example_telemetry("run_clm", model_args, data_args, framework="tensorflow")

    # Sanity checks
    if data_args.dataset_name is None and data_args.train_file is None and data_args.validation_file is None:
        raise ValueError("Need either a dataset name or a training/validation file.")
    else:
        if data_args.train_file is not None:
            extension = data_args.train_file.split(".")[-1]
            assert extension in ["csv", "json", "txt"], "`train_file` should be a csv, json or txt file."
        if data_args.validation_file is not None:
            extension = data_args.validation_file.split(".")[-1]
            assert extension in ["csv", "json", "txt"], "`validation_file` should be a csv, json or txt file."

    if training_args.output_dir is not None:
        training_args.output_dir = Path(training_args.output_dir)
        os.makedirs(training_args.output_dir, exist_ok=True)
    # endregion

    # region Checkpoints
    # Detecting last checkpoint.
    checkpoint = None
    if len(os.listdir(training_args.output_dir)) > 0 and not training_args.overwrite_output_dir:
        config_path = training_args.output_dir / CONFIG_NAME
        weights_path = training_args.output_dir / TF2_WEIGHTS_NAME
        if config_path.is_file() and weights_path.is_file():
            checkpoint = training_args.output_dir
            logger.info(
                f"Checkpoint detected, resuming training from checkpoint in {training_args.output_dir}. To avoid this"
                " behavior, change the `--output_dir` or add `--overwrite_output_dir` to train from scratch."
            )
        else:
            raise ValueError(
                f"Output directory ({training_args.output_dir}) already exists and is not empty. "
                "Use --overwrite_output_dir to continue regardless."
            )

    # endregion

    # region Setup logging
    # accelerator.is_local_main_process is only True for one process per machine.
    logger.setLevel(logging.INFO)
    datasets.utils.logging.set_verbosity_warning()
    transformers.utils.logging.set_verbosity_info()
    # endregion

    # If passed along, set the training seed now.
    if training_args.seed is not None:
        set_seed(training_args.seed)

    # region Load datasets
    # Get the datasets: you can either provide your own CSV/JSON/TXT training and evaluation files (see below)
    # or just provide the name of one of the public datasets available on the hub at https://huggingface.co/datasets/
    # (the dataset will be downloaded automatically from the datasets Hub).
    #
    # For CSV/JSON files, this script will use the column called 'text' or the first column if no column called
    # 'text' is found. You can easily tweak this behavior (see below).
    #
    # In distributed training, the load_dataset function guarantee that only one local process can concurrently
    # download the dataset.
    if data_args.dataset_name is not None:
        # Downloading and loading a dataset from the hub.
        raw_datasets = load_dataset(
            data_args.dataset_name,
            data_args.dataset_config_name,
            cache_dir=model_args.cache_dir,
            use_auth_token=True if model_args.use_auth_token else None,
        )
        if "validation" not in raw_datasets.keys():
            raw_datasets["validation"] = load_dataset(
                data_args.dataset_name,
                data_args.dataset_config_name,
                split=f"train[:{data_args.validation_split_percentage}%]",
                cache_dir=model_args.cache_dir,
                use_auth_token=True if model_args.use_auth_token else None,
            )
            raw_datasets["train"] = load_dataset(
                data_args.dataset_name,
                data_args.dataset_config_name,
                split=f"train[{data_args.validation_split_percentage}%:]",
                cache_dir=model_args.cache_dir,
                use_auth_token=True if model_args.use_auth_token else None,
            )
    else:
        data_files = {}
        dataset_args = {}
        if data_args.train_file is not None:
            data_files["train"] = data_args.train_file
        if data_args.validation_file is not None:
            data_files["validation"] = data_args.validation_file
        extension = (
            data_args.train_file.split(".")[-1]
            if data_args.train_file is not None
            else data_args.validation_file.split(".")[-1]
        )
        if extension == "txt":
            extension = "text"
            dataset_args["keep_linebreaks"] = data_args.keep_linebreaks
        raw_datasets = load_dataset(
            extension,
            data_files=data_files,
            cache_dir=model_args.cache_dir,
            use_auth_token=True if model_args.use_auth_token else None,
            **dataset_args,
        )
        # If no validation data is there, validation_split_percentage will be used to divide the dataset.
        if "validation" not in raw_datasets.keys():
            raw_datasets["validation"] = load_dataset(
                extension,
                data_files=data_files,
                split=f"train[:{data_args.validation_split_percentage}%]",
                cache_dir=model_args.cache_dir,
                use_auth_token=True if model_args.use_auth_token else None,
                **dataset_args,
            )
            raw_datasets["train"] = load_dataset(
                extension,
                data_files=data_files,
                split=f"train[{data_args.validation_split_percentage}%:]",
                cache_dir=model_args.cache_dir,
                use_auth_token=True if model_args.use_auth_token else None,
                **dataset_args,
            )
    # See more about loading any type of standard or custom dataset (from files, python dict, pandas DataFrame, etc) at
    # https://huggingface.co/docs/datasets/loading_datasets.html.
    # endregion

    # region Load pretrained model and tokenizer
    #
    # In distributed training, the .from_pretrained methods guarantee that only one local process can concurrently
    # download model & vocab.
    if model_args.config_name:
        config = AutoConfig.from_pretrained(model_args.config_name)
    elif model_args.model_name_or_path:
        config = AutoConfig.from_pretrained(model_args.model_name_or_path)
    else:
        config = CONFIG_MAPPING[model_args.model_type]()
        logger.warning("You are instantiating a new config instance from scratch.")

    if model_args.tokenizer_name:
        tokenizer = AutoTokenizer.from_pretrained(model_args.tokenizer_name)
    elif model_args.model_name_or_path:
        tokenizer = AutoTokenizer.from_pretrained(model_args.model_name_or_path)
    else:
        raise ValueError(
            "You are instantiating a new tokenizer from scratch. This is not supported by this script."
            "You can do it from another script, save it, and load it from here, using --tokenizer_name."
        )
    # endregion

    # region Dataset preprocessing
    # First we tokenize all the texts.
    column_names = raw_datasets["train"].column_names
    text_column_name = "text" if "text" in column_names else column_names[0]

    def tokenize_function(examples):
        return tokenizer(examples[text_column_name])

    tokenized_datasets = raw_datasets.map(
        tokenize_function,
        batched=True,
        num_proc=data_args.preprocessing_num_workers,
        remove_columns=column_names,
        load_from_cache_file=not data_args.overwrite_cache,
        desc="Running tokenizer on dataset",
    )

    if data_args.block_size is None:
        block_size = tokenizer.model_max_length
        if block_size > 1024:
            logger.warning(
                f"The tokenizer picked seems to have a very large `model_max_length` ({tokenizer.model_max_length}). "
                "Picking 1024 instead. You can change that default value by passing --block_size xxx."
            )
            block_size = 1024
    else:
        if data_args.block_size > tokenizer.model_max_length:
            logger.warning(
                f"The block_size passed ({data_args.block_size}) is larger than the maximum length for the model"
                f"({tokenizer.model_max_length}). Using block_size={tokenizer.model_max_length}."
            )
        block_size = min(data_args.block_size, tokenizer.model_max_length)

    # Main data processing function that will concatenate all texts from our dataset and generate chunks of block_size.
    def group_texts(examples):
        # Concatenate all texts.
        concatenated_examples = {k: list(chain(*examples[k])) for k in examples.keys()}
        total_length = len(concatenated_examples[list(examples.keys())[0]])
        # We drop the small remainder, we could add padding if the model supported it instead of this drop, you can
        # customize this part to your needs.
        if total_length >= block_size:
            total_length = (total_length // block_size) * block_size
        # Split by chunks of max_len.
        result = {
            k: [t[i : i + block_size] for i in range(0, total_length, block_size)]
            for k, t in concatenated_examples.items()
        }
        result["labels"] = result["input_ids"].copy()
        return result

    # Note that with `batched=True`, this map processes 1,000 texts together, so group_texts throws away a remainder
    # for each of those groups of 1,000 texts. You can adjust that batch_size here but a higher value might be slower
    # to preprocess.
    #
    # To speed up this part, we use multiprocessing. See the documentation of the map method for more information:
    # https://huggingface.co/docs/datasets/package_reference/main_classes.html#datasets.Dataset.map

    lm_datasets = tokenized_datasets.map(
        group_texts,
        batched=True,
        num_proc=data_args.preprocessing_num_workers,
        load_from_cache_file=not data_args.overwrite_cache,
        desc=f"Grouping texts in chunks of {block_size}",
    )

    train_dataset = lm_datasets["train"]
    if data_args.validation_file is not None:
        eval_dataset = lm_datasets["validation"]
    else:
        logger.info(
            f"Validation file not found: using {data_args.validation_split_percentage}% of the dataset as validation"
            " as provided in data_args"
        )
        train_indices, val_indices = train_test_split(
            list(range(len(train_dataset))), test_size=data_args.validation_split_percentage / 100
        )

        eval_dataset = train_dataset.select(val_indices)
        train_dataset = train_dataset.select(train_indices)

    if data_args.max_train_samples is not None:
        max_train_samples = min(len(train_dataset), data_args.max_train_samples)
        train_dataset = train_dataset.select(range(max_train_samples))
    if data_args.max_eval_samples is not None:
        max_eval_samples = min(len(eval_dataset), data_args.max_eval_samples)
        eval_dataset = eval_dataset.select(range(max_eval_samples))

    # Log a few random samples from the training set:
    for index in random.sample(range(len(train_dataset)), min(3, len(train_dataset))):
        logger.info(f"Sample {index} of the training set: {train_dataset[index]}.")
    # endregion

    with training_args.strategy.scope():
        # region Prepare model
        if checkpoint is not None:
            model = TFAutoModelForCausalLM.from_pretrained(checkpoint, config=config)
        elif model_args.model_name_or_path:
            model = TFAutoModelForCausalLM.from_pretrained(model_args.model_name_or_path, config=config)
        else:
            logger.info("Training new model from scratch")
            model = TFAutoModelForCausalLM.from_config(config)

        # We resize the embeddings only when necessary to avoid index errors. If you are creating a model from scratch
        # on a small vocab and want a smaller embedding size, remove this test.
        embeddings = model.get_input_embeddings()

        # Matt: This is a temporary workaround as we transition our models to exclusively using Keras embeddings.
        #       As soon as the transition is complete, all embeddings should be keras.Embeddings layers, and
        #       the weights will always be in embeddings.embeddings.
        if hasattr(embeddings, "embeddings"):
            embedding_size = embeddings.embeddings.shape[0]
        else:
            embedding_size = embeddings.weight.shape[0]
        if len(tokenizer) > embedding_size:
            model.resize_token_embeddings(len(tokenizer))
        # endregion

        # region TF Dataset preparation
        num_replicas = training_args.strategy.num_replicas_in_sync
        options = tf.data.Options()
        options.experimental_distribute.auto_shard_policy = tf.data.experimental.AutoShardPolicy.OFF

        # model.prepare_tf_dataset() wraps a Hugging Face dataset in a tf.data.Dataset which is ready to use in
        # training. This is the recommended way to use a Hugging Face dataset when training with Keras. You can also
        # use the lower-level dataset.to_tf_dataset() method, but you will have to specify things like column names
        # yourself if you use this method, whereas they are automatically inferred from the model input names when
        # using model.prepare_tf_dataset()
        # For more info see the docs:
        # https://huggingface.co/docs/transformers/main/en/main_classes/model#transformers.TFPreTrainedModel.prepare_tf_dataset
        # https://huggingface.co/docs/datasets/main/en/package_reference/main_classes#datasets.Dataset.to_tf_dataset

        tf_train_dataset = model.prepare_tf_dataset(
            train_dataset,
            shuffle=True,
            batch_size=num_replicas * training_args.per_device_train_batch_size,
        ).with_options(options)

        tf_eval_dataset = model.prepare_tf_dataset(
            eval_dataset,
            shuffle=False,
            batch_size=num_replicas * training_args.per_device_eval_batch_size,
            drop_remainder=True,
        ).with_options(options)
        # endregion

        # region Optimizer and loss
        num_train_steps = len(tf_train_dataset) * int(training_args.num_train_epochs)
        if training_args.warmup_steps > 0:
            num_warmup_steps = training_args.warmup_steps
        elif training_args.warmup_ratio > 0:
            num_warmup_steps = int(num_train_steps * training_args.warmup_ratio)
        else:
            num_warmup_steps = 0

        # Bias and layernorm weights are automatically excluded from the decay
        optimizer, lr_schedule = create_optimizer(
            init_lr=training_args.learning_rate,
            num_train_steps=num_train_steps,
            num_warmup_steps=num_warmup_steps,
            adam_beta1=training_args.adam_beta1,
            adam_beta2=training_args.adam_beta2,
            adam_epsilon=training_args.adam_epsilon,
            weight_decay_rate=training_args.weight_decay,
            adam_global_clipnorm=training_args.max_grad_norm,
        )

        # no user-specified loss = will use the model internal loss
        model.compile(optimizer=optimizer, jit_compile=training_args.xla)
        # endregion

        # region Preparing push_to_hub and model card
        push_to_hub_model_id = training_args.push_to_hub_model_id
        model_name = model_args.model_name_or_path.split("/")[-1]
        if not push_to_hub_model_id:
            if data_args.dataset_name is not None:
                push_to_hub_model_id = f"{model_name}-finetuned-{data_args.dataset_name}"
            else:
                push_to_hub_model_id = f"{model_name}-finetuned-clm"

        model_card_kwargs = {"finetuned_from": model_args.model_name_or_path, "tasks": "text-generation"}
        if data_args.dataset_name is not None:
            model_card_kwargs["dataset_tags"] = data_args.dataset_name
            if data_args.dataset_config_name is not None:
                model_card_kwargs["dataset_args"] = data_args.dataset_config_name
                model_card_kwargs["dataset"] = f"{data_args.dataset_name} {data_args.dataset_config_name}"
            else:
                model_card_kwargs["dataset"] = data_args.dataset_name

        if training_args.push_to_hub:
            callbacks = [
                PushToHubCallback(
                    output_dir=training_args.output_dir,
                    hub_model_id=push_to_hub_model_id,
                    hub_token=training_args.push_to_hub_token,
                    tokenizer=tokenizer,
                    **model_card_kwargs,
                )
            ]
        else:
            callbacks = []
        # endregion

        # region Training and validation
        logger.info("***** Running training *****")
        logger.info(f"  Num examples = {len(train_dataset)}")
        logger.info(f"  Num Epochs = {training_args.num_train_epochs}")
        logger.info(f"  Instantaneous batch size per device = {training_args.per_device_train_batch_size}")
        logger.info(f"  Total train batch size = {training_args.per_device_train_batch_size * num_replicas}")

        # For long training runs, you may wish to use the PushToHub() callback here to save intermediate checkpoints
        # to the Hugging Face Hub rather than just pushing the finished model.
        # See https://huggingface.co/docs/transformers/main_classes/keras_callbacks#transformers.PushToHubCallback

        history = model.fit(
            tf_train_dataset,
            validation_data=tf_eval_dataset,
            epochs=int(training_args.num_train_epochs),
            callbacks=callbacks,
        )
        train_loss = history.history["loss"][-1]
        try:
            train_perplexity = math.exp(train_loss)
        except OverflowError:
            train_perplexity = math.inf
        logger.info(f"  Final train loss: {train_loss:.3f}")
        logger.info(f"  Final train perplexity: {train_perplexity:.3f}")
        validation_loss = history.history["val_loss"][-1]
        try:
            validation_perplexity = math.exp(validation_loss)
        except OverflowError:
            validation_perplexity = math.inf
        logger.info(f"  Final validation loss: {validation_loss:.3f}")
        logger.info(f"  Final validation perplexity: {validation_perplexity:.3f}")

        if training_args.output_dir is not None:
            output_eval_file = os.path.join(training_args.output_dir, "all_results.json")
            results_dict = {}
            results_dict["train_loss"] = train_loss
            results_dict["train_perplexity"] = train_perplexity
            results_dict["eval_loss"] = validation_loss
            results_dict["eval_perplexity"] = validation_perplexity
            with open(output_eval_file, "w") as writer:
                writer.write(json.dumps(results_dict))
        # endregion

    if training_args.output_dir is not None and not training_args.push_to_hub:
        # If we're not pushing to hub, at least save a local copy when we're done
        model.save_pretrained(training_args.output_dir)