mirror of https://github.com/hpcaitech/ColossalAI
184 lines
7.9 KiB
Python
184 lines
7.9 KiB
Python
#!/usr/bin/env python3
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# -*- coding: utf-8 -*-
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"""
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Splicing multiple pre-tokenized sequence data points
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"""
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import random
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import warnings
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from copy import deepcopy
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from datasets import dataset_dict
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from typing import Any, Callable, Dict, Iterable, List, Union, Tuple
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from torch.utils.data import ConcatDataset, Dataset, IterableDataset
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from transformers.models.llama.tokenization_llama import LlamaTokenizer
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from transformers.tokenization_utils import PreTrainedTokenizer
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IGNORE_INDEX = -100
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DSType = Union[Dataset, ConcatDataset, dataset_dict.Dataset]
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def supervised_tokenize(
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data_point: Dict[str, str], tokenizer: LlamaTokenizer, ignore_index: int = None, max_length: int = 4096
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) -> Dict[str, Union[int, str, List[int]]]:
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"""
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A tokenization function to tokenize an original pretraining data point as following:
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{"source": "", "target": "Beijing, the capital of the People's Republic of China, ...", "category": "geography"}
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"""
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assert tokenizer.add_bos_token is False and tokenizer.add_eos_token is False, (
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"Initially set `tokenizer.add_bos_token` and `tokenizer.add_eos_token` to False, "
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"add <bos> and <eos> manually later"
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)
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if ignore_index is None:
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ignore_index = IGNORE_INDEX
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source_text = data_point["source"] # `str`
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target_text = data_point["target"] # `str`
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is_null_source = len(source_text) == 0
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source_text = tokenizer.bos_token + source_text
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target_text += tokenizer.eos_token
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sequence_text = source_text + target_text
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tokenized = tokenizer([source_text, sequence_text])["input_ids"]
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sequence_input_ids = tokenized[1]
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sequence_labels = deepcopy(sequence_input_ids)
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source_length = len(tokenized[0])
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if not is_null_source:
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sequence_labels[:source_length] = [ignore_index for _ in range(source_length)]
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# sequence truncation.
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if len(sequence_input_ids) > max_length:
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sequence_input_ids = sequence_input_ids[:max_length]
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sequence_labels = sequence_labels[:max_length]
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return dict(
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input_ids=sequence_input_ids,
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labels=sequence_labels,
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seq_length=len(sequence_input_ids),
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seq_category=data_point["category"],
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)
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class ClosedToConstantLengthSplicedDataset(IterableDataset):
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"""
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Define an iterable dataset that returns a (close to) constant length data point spliced from multiple
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original independent (pre-tokenized) data points.
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"""
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def __init__(
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self,
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dataset: DSType,
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tokenizer: PreTrainedTokenizer,
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max_length: int = 4096,
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num_packed_sequences: int = 8,
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fetch_sequence_func: Callable[[Any], Tuple[List[int], List[int]]] = None,
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input_ids_field: str = "input_ids",
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labels_field: str = "labels",
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infinite: bool = False,
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shuffle: bool = True,
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error_strict: bool = False,
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) -> None:
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self.tokenizer = tokenizer
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self.dataset = dataset
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self.max_length = max_length
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self.infinite = infinite
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self.max_buffer_size = max_length * num_packed_sequences # e.g., 4096 * 16
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self.shuffle = shuffle
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# Callable[[Dict[str, Any]], Tuple[List[int], List[int]]],
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# A function that fetch sequence input_ids and labels from the original data point
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if fetch_sequence_func is None:
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self.fetch_sequence_func = lambda data_point: (data_point[input_ids_field], data_point[labels_field])
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else:
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self.fetch_sequence_func = fetch_sequence_func
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self.input_ids_field = input_ids_field
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self.labels_field = labels_field
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self.error_strict = error_strict
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self.current_size = 0 # `int`, current packed data size.
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def __len__(self) -> int:
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return len(self.dataset)
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def __iter__(self) -> Iterable[Dict[str, List[int]]]:
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iterator = iter(self.dataset)
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more_data_points = True
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while more_data_points is True:
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buffer, buffer_len = [], 0
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while True:
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# ending condition.
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if buffer_len >= self.max_buffer_size:
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break
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try:
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# `Tuple[List[int], List[int]]`
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seq_input_ids, seq_labels = self.fetch_sequence_func(next(iterator))
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buffer.append({self.input_ids_field: seq_input_ids, self.labels_field: seq_labels})
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buffer_len += len(buffer[-1][self.input_ids_field])
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except StopIteration:
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if self.infinite is True:
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iterator = iter(self.dataset)
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warnings.warn("The dataset reached end and the iterator is reset to the start.")
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else:
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more_data_points = False
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break
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examples = [] # `List[Dict[str, List[int]]]`, save buffered spliced data points.
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spliced_input_ids, spliced_labels = [], [] # `List[int]`, `List[int]`
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for i, data_point in enumerate(buffer):
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# TODO(2023-09-18) check errors for each unspliced tokenized data point
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seq_input_ids = data_point[self.input_ids_field]
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seq_labels = data_point[self.labels_field]
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# Handle special case:
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# If the length of an original data point (i.e., input_ids length of a data point before splicing)
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# exceeds `max_length`, truncate it.
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if len(seq_input_ids) > self.max_length:
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truncated_seq_input_ids = seq_input_ids[: self.max_length]
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truncated_label_ids = seq_labels[: self.max_length]
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if set(truncated_label_ids) == {IGNORE_INDEX}:
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if self.error_strict is True:
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raise ValueError(
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f"Find an out-of-bounds length({len(seq_input_ids)}) data point "
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f"with all label values as {IGNORE_INDEX}."
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)
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else:
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warnings.warn(f"Filter an error truncated data point (labels all {IGNORE_INDEX})")
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continue # Skip the current error data point.
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spliced_data_point = {
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self.input_ids_field: truncated_seq_input_ids,
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self.labels_field: truncated_label_ids,
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}
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examples.append(spliced_data_point)
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warnings.warn("Find a data point to be truncated.")
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continue
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# Pre action judgment.
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if len(spliced_input_ids) + len(seq_input_ids) > self.max_length:
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spliced_data_point = {
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self.input_ids_field: spliced_input_ids,
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self.labels_field: spliced_labels,
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} # `Dict[str, List[int]]`
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# Update.
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spliced_input_ids, spliced_labels = [], []
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spliced_input_ids.extend(seq_input_ids)
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spliced_labels.extend(seq_labels)
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examples.append(spliced_data_point)
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else:
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spliced_input_ids.extend(seq_input_ids)
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spliced_labels.extend(seq_labels)
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# For residual spliced data point at the end of the data set
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if self.infinite is False and more_data_points is False and len(spliced_input_ids) > 0:
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examples.append(
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{
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self.input_ids_field: spliced_input_ids,
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self.labels_field: spliced_labels
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}
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)
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if self.shuffle:
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random.shuffle(examples)
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for spliced_data_point in examples:
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# TODO(2023-09-18): check errors for each spliced tokenized data point.
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self.current_size += 1
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yield spliced_data_point
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