[Training] Datasets - update Module (#1209)

Order of reviews:
#1206
#1207
#1209 <-- Here
#1212
#1214 

SUMMARY:
* Move dataset logic out of transformers module
`src/llmcompressor/transformers/finetune/data/data_helpers.py`, add it
to `src/llmcompressor/datasets/utils.py`


TEST PLAN:
Pass tests

Author: George

src/llmcompressor/datasets/__init__.py

@@ -0,0 +1,8 @@
+# flake8: noqa
+
+from .utils import (
+    format_calibration_data,
+    get_calibration_dataloader,
+    get_processed_dataset,
+    make_dataset_splits,
+)

src/llmcompressor/datasets/utils.py

@@ -0,0 +1,191 @@
+import re
+from typing import Any, Callable, Dict, List, Optional
+
+import torch
+from datasets import Dataset
+from loguru import logger
+from torch.utils.data import DataLoader, RandomSampler, SequentialSampler
+from transformers.data import default_data_collator
+
+from llmcompressor.args import DatasetArguments
+from llmcompressor.transformers.finetune.data import TextGenerationDataset
+from llmcompressor.typing import Processor
+
+
+def get_processed_dataset(
+    dataset_args: DatasetArguments,
+    processor: Processor,
+    do_oneshot: bool = False,
+    do_train: bool = True,
+) -> Optional[Dict[str, Dataset]]:
+    """
+    Loads datasets for each flow based on dataset_args, stores a Dataset for each
+    enabled flow in datasets
+    :param dataset_args: DatasetArguments that contain dataset loading and
+        processing params
+    :param processor: processor or tokenizer to use for dataset tokenization
+    :param do_oneshot: True for oneshot pathway
+    :param do_train: True for train pathway
+    :return: A dataset corresponding to either train or calibration (oneshot)
+    """
+    if dataset_args.dataset is None:
+        logger.warning(
+            "Running oneshot without calibration data. This is expected for "
+            "weight-only and dynamic quantization"
+        )
+        return
+
+    splits = dataset_args.splits
+    tokenized_datasets = {}
+
+    def _get_split_name(inp_str):
+        # strip out split name, for ex train[60%:] -> train
+        match = re.match(r"(\w*)\[.*\]", inp_str)
+        if match is not None:
+            return match.group(1)
+        return inp_str
+
+    if splits is None:
+        splits = {"all": None}
+    elif isinstance(splits, str):
+        splits = {_get_split_name(splits): splits}
+    elif isinstance(splits, List):
+        splits = {_get_split_name(s): s for s in splits}
+
+    # default to custom dataset if dataset provided isn't a string
+    registry_id = (
+        dataset_args.dataset if isinstance(dataset_args.dataset, str) else "custom"
+    )
+    for split_name, split_str in splits.items():
+        dataset = dataset_args.dataset
+        if hasattr(dataset, "column_names") and "input_ids" in dataset.column_names:
+            # dataset is already tokenized
+            tokenized_datasets[split_name] = dataset
+        else:
+            # dataset needs to be tokenized
+            dataset_manager = TextGenerationDataset.load_from_registry(
+                registry_id,
+                dataset_args=dataset_args,
+                split=split_str,
+                processor=processor,
+            )
+            tokenized_datasets[split_name] = dataset_manager(add_labels=do_train)
+
+    return make_dataset_splits(
+        tokenized_datasets,
+        do_oneshot=do_oneshot,
+        do_train=do_train,
+    )
+
+
+def get_calibration_dataloader(
+    dataset_args: DatasetArguments,
+    processor: Processor,
+) -> torch.utils.data.DataLoader:
+    """
+    Get the dataloader used for oneshot calibration.
+    :param dataset_args: DatasetArguments that contains the dataset parameters.
+    :param processor: Processor or the tokenizer of the model.
+    :return: PyTorch dataloader object that contains the calibration dataset.
+    """
+    if dataset_args.dataset is None:
+        # weight-only quantization or dynamic quantization
+        return
+
+    datasets = get_processed_dataset(
+        dataset_args=dataset_args,
+        processor=processor,
+        do_oneshot=True,
+        do_train=False,
+    )
+
+    calibration_dataset = datasets.get("calibration")
+
+    return format_calibration_data(
+        tokenized_dataset=calibration_dataset,
+        num_calibration_samples=dataset_args.num_calibration_samples,
+        do_shuffle=dataset_args.shuffle_calibration_samples,
+        collate_fn=dataset_args.data_collator,
+    )
+
+
+def format_calibration_data(
+    tokenized_dataset: Dataset,
+    num_calibration_samples: Optional[int] = None,
+    do_shuffle: bool = True,
+    collate_fn: Callable = default_data_collator,
+) -> List[torch.Tensor]:
+    """
+    Creates a dataloader out of the calibration dataset split, trimming it to
+    the desired number of calibration samples
+    :param tokenized_dataset: dataset to convert to dataloader
+    :param num_calibration_samples: number of data samples to convert
+    :param do_shuffle: whether to shuffle the dataset before selecting calibration
+        samples, true by default
+    :param collate_fn: optional custom collate function, or use default
+    :return: list of trimmed calibration data tensors
+    """
+    safe_calibration_samples = len(tokenized_dataset)
+    if num_calibration_samples is not None:
+        safe_calibration_samples = min(len(tokenized_dataset), num_calibration_samples)
+        if safe_calibration_samples != num_calibration_samples:
+            logger.warn(
+                f"Requested {num_calibration_samples} calibration samples but "
+                f"the provided dataset only has {safe_calibration_samples}. "
+            )
+
+    if do_shuffle:
+        tokenized_dataset = tokenized_dataset.shuffle()
+    tokenized_calibration = tokenized_dataset.select(range(safe_calibration_samples))
+
+    dataloader_params = {
+        "batch_size": 1,
+        "sampler": RandomSampler(tokenized_calibration)
+        if do_shuffle
+        else SequentialSampler(tokenized_calibration),
+        "collate_fn": collate_fn,
+        "pin_memory": True,
+    }
+
+    calibration_dataloader = DataLoader(tokenized_calibration, **dataloader_params)
+
+    return calibration_dataloader
+
+
+def make_dataset_splits(
+    tokenized_datasets: Dict[str, Any],
+    do_oneshot: bool = True,
+    do_train: bool = False,
+) -> Dict[str, Dataset]:
+    """
+    Restructures the datasets dictionary based on what tasks will be run
+    train
+    :param tokenized_datasets: dictionary of processed datasets
+    :param do_oneshot: Whether to store the calibration dataset
+    :return: A dataset corresponding to either train or calibration (oneshot)
+    """
+
+    # handles case where all splits are contained in a single dataset
+    if "all" in tokenized_datasets and len(tokenized_datasets) == 1:
+        tokenized_datasets = tokenized_datasets.get("all")
+        if isinstance(tokenized_datasets, Dataset):
+            tokenized_datasets = {"train": tokenized_datasets}
+
+    train_split = calib_split = None
+
+    if do_train:
+        if "train" not in tokenized_datasets:
+            raise ValueError("--do_train requires a train dataset")
+        train_split = tokenized_datasets["train"]
+    if do_oneshot:
+        calib_split = tokenized_datasets.get("calibration")
+        if calib_split is None:
+            if "train" not in tokenized_datasets:
+                raise ValueError("--do_oneshot requires a calibration dataset")
+            calib_split = tokenized_datasets["train"]
+
+    split_datasets = {
+        "train": train_split,
+        "calibration": calib_split,
+    }
+    return split_datasets

src/llmcompressor/entrypoints/oneshot.py

@@ -7,9 +7,7 @@
 
 from llmcompressor.args import parse_args
 from llmcompressor.core.session_functions import active_session
-from llmcompressor.transformers.finetune.data.data_helpers import (
-    get_calibration_dataloader,
-)
+from llmcompressor.datasets import get_calibration_dataloader
 from llmcompressor.transformers.finetune.text_generation import (
     initialize_model_from_path,
     initialize_processor_from_path,