191 lines
7.1 KiB
Python
191 lines
7.1 KiB
Python
import torch
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import bisect
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from abc import ABC, abstractmethod
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from torch import Tensor
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from torch.utils.data import Dataset
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from khaosz.data.mmap import MmapFileHandler
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from typing import Callable, List, Dict, Literal, Optional, Union
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Seg = List[Tensor]
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MultiSeg = Dict[str, Seg]
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class BaseSegmentFetcher:
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def __init__(self, segments: Seg):
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self.segments = segments
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self.cum_lengths = []
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total = 0
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for seg in segments:
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total += len(seg)
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self.cum_lengths.append(total)
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self.total_length = total if segments else 0
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def fetch_data(self, begin_idx: int, end_idx: int) -> Tensor:
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if not (0 <= begin_idx < self.total_length and 0 <= end_idx <= self.total_length):
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raise ValueError("begin_idx or end_idx out of bounds")
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if begin_idx >= end_idx:
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return torch.tensor([], dtype=torch.long)
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# fix the range index bug
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seg_start_idx = bisect.bisect_right(self.cum_lengths, begin_idx)
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seg_end_idx = bisect.bisect_left(self.cum_lengths, end_idx)
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result_segments = []
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for i in range(seg_start_idx, seg_end_idx + 1):
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prev_cum = self.cum_lengths[i - 1] if i > 0 else 0
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start = max(begin_idx - prev_cum, 0)
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end = min(end_idx - prev_cum, len(self.segments[i]))
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result_segments.append(self.segments[i][start:end])
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return torch.cat(result_segments, dim=0)
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class MultiSegmentFetcher:
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def __init__(self, muti_segments: MultiSeg):
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self.muti_keys = list(muti_segments.keys())
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self.muti_fetchers = {
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key: BaseSegmentFetcher(segments)
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for key, segments in muti_segments.items()
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}
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def key_fetch(self, begin_idx: int, end_idx: int, keys: Union[str, List[str]]) -> Union[Tensor, Seg]:
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fetch_dict = {}
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keys = [keys] if isinstance(keys, str) else keys
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for key in keys:
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fetcher = self.muti_fetchers[key]
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fetch_tensor = fetcher.fetch_data(begin_idx, end_idx)
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fetch_dict[key] = fetch_tensor
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return fetch_dict if len(keys) > 1 else fetch_dict[keys[0]]
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def fetch_data(self, begin_idx: int, end_idx: int) -> Union[Tensor, Seg]:
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return self.key_fetch(begin_idx, end_idx, self.muti_keys)
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class BaseDataset(Dataset, ABC):
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def __init__(self, window_size: int, stride: int):
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super().__init__()
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self.segments: MultiSeg = {}
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self.window_size = window_size
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self.stride = stride
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self.total_samples = None
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def load(self, load_path: str):
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self.segments, self.total_samples = MmapFileHandler.load(load_path)
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self.fetcher = MultiSegmentFetcher(self.segments)
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def get_index(self, index: int) -> int:
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begin_idx = min(index * self.stride, self.total_samples - self.window_size - 1)
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end_idx = begin_idx + self.window_size
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return begin_idx, end_idx
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@abstractmethod
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def __getitem__(self, index: int) -> Dict[str, Tensor]:
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raise NotImplementedError
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def __len__(self) -> int:
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assert self.total_samples is not None
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if self.total_samples <= self.window_size:
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return 0
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return self.total_samples // self.stride + 1
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class SeqDataset(BaseDataset):
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def __init__(self, window_size: int, stride: int):
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super().__init__(window_size, stride)
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self.fetcher = MultiSegmentFetcher(self.segments)
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def _fetch_data(self, begin_idx: int, end_idx: int) -> Tensor:
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return self.fetcher.key_fetch(begin_idx, end_idx, "sequence")
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def __getitem__(self, index):
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# fix the range index bug
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begin_idx, end_idx = self.get_index(index)
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x = self._fetch_data(begin_idx, end_idx).to(dtype=torch.long)
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y = self._fetch_data(begin_idx + 1, end_idx + 1).to(dtype=torch.long)
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return {"input_ids": x, "target_ids": y}
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class SftDataset(BaseDataset):
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def __init__(self, window_size: int, stride: int):
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super().__init__(window_size, stride)
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self.fetcher = MultiSegmentFetcher(self.segments)
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def _fetch_data(self, begin_idx: int, end_idx: int, key: str) -> Tensor:
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return self.fetcher.key_fetch(begin_idx, end_idx, key)
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def __getitem__(self, index):
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begin_idx, end_idx = self.get_index(index)
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x = self._fetch_data(begin_idx, end_idx, "sequence").to(dtype=torch.long)
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y = self._fetch_data(begin_idx + 1, end_idx + 1, "sequence").to(dtype=torch.long)
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loss_mask = self._fetch_data(begin_idx + 1, end_idx + 1, "loss_mask").to(dtype=torch.bool)
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return {"input_ids": x, "target_ids": y, "loss_mask": loss_mask}
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class DpoDataset(BaseDataset):
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def __init__(self, window_size: int, stride: int):
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super().__init__(window_size, stride)
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self.fetcher = MultiSegmentFetcher(self.segments)
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def _fetch_data(self, begin_idx: int, end_idx: int, key: str) -> Tensor:
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return self.fetcher.key_fetch(begin_idx, end_idx, key)
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def __getitem__(self, index: int):
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begin_idx, end_idx = self.get_index(index)
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chosen = self._fetch_data(begin_idx, end_idx, "chosen").to(dtype=torch.long)
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rejected = self._fetch_data(begin_idx, end_idx, "rejected").to(dtype=torch.long)
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chosen_mask = self._fetch_data(begin_idx, end_idx, "chosen_mask").to(dtype=torch.bool)
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rejected_mask = self._fetch_data(begin_idx, end_idx, "rejected_mask").to(dtype=torch.bool)
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return {"chosen": chosen, "rejected": rejected, "chosen_mask": chosen_mask, "rejected_mask": rejected_mask}
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class PpoDataset(BaseDataset):
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def __init__(self, window_size: int, stride: int):
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super().__init__(window_size, stride)
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self.fetcher = MultiSegmentFetcher(self.segments)
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def _fetch_data(self, begin_idx: int, end_idx: int, key: str) -> Tensor:
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return self.fetcher.key_fetch(begin_idx, end_idx, key)
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def __getitem__(self, index: int) -> Dict[str, Tensor]:
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begin_idx, end_idx = self.get_index(index)
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input_ids = self._fetch_data(begin_idx, end_idx, "input_ids"),
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actions = self._fetch_data(begin_idx, end_idx, "actions"),
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logprobs = self._fetch_data(begin_idx, end_idx, "logprobs"),
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rewards = self._fetch_data(begin_idx, end_idx, "rewards")
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return {"input_ids": input_ids, "actions": actions, "logprobs": logprobs, "rewards": rewards}
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class DatasetLoader:
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@staticmethod
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def load(
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train_type: Literal["seq", "sft", "dpo"],
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load_path: str,
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window_size: int,
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stride: Optional[int] = None,
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) -> BaseDataset:
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if stride is None:
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stride = window_size
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dataset_router: Dict[str, Callable[[int], BaseDataset]] = {
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"seq": lambda window_size: SeqDataset(window_size, stride),
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"sft": lambda window_size: SftDataset(window_size, stride),
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"dpo": lambda window_size: DpoDataset(window_size, stride),
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}
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dataset = dataset_router[train_type](window_size)
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dataset.load(load_path)
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return dataset
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