192 lines
7.5 KiB
Python
192 lines
7.5 KiB
Python
from torch.utils.data import Dataset
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import torch
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import os
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from datasets import load_dataset
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os.environ["TOKENIZERS_PARALLELISM"] = "false"
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class PretrainDataset(Dataset):
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def __init__(self, data_path, tokenizer, max_length=512):
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super().__init__()
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self.tokenizer = tokenizer
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self.max_length = max_length
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self.samples = load_dataset('json', data_files=data_path, split='train')
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def __len__(self):
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return len(self.samples)
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def __getitem__(self, index):
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sample = self.samples[index]
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encoding = self.tokenizer(
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str(sample['text']),
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max_length=self.max_length,
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padding='max_length',
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truncation=True,
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return_tensors='pt'
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)
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input_ids = encoding.input_ids.squeeze()
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labels = input_ids.clone()
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labels[input_ids == self.tokenizer.pad_token_id] = -100
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return input_ids, labels
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class SFTDataset(Dataset):
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def __init__(self, jsonl_path, tokenizer, max_length=1024):
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super().__init__()
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self.tokenizer = tokenizer
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self.max_length = max_length
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self.samples = load_dataset('json', data_files=jsonl_path, split='train')
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self.bos_id = tokenizer(f'{tokenizer.bos_token}assistant\n', add_special_tokens=False).input_ids
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self.eos_id = tokenizer(f'{tokenizer.eos_token}\n', add_special_tokens=False).input_ids
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def __len__(self):
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return len(self.samples)
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def create_chat_prompt(self, cs):
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messages = cs.copy()
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tools = cs[0]["functions"] if (cs and cs[0]["role"] == "system" and cs[0].get("functions")) else None
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return self.tokenizer.apply_chat_template(
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messages,
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tokenize=False,
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add_generation_prompt=False,
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tools=tools
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)
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def generate_labels(self, input_ids):
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labels = [-100] * len(input_ids)
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i = 0
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while i < len(input_ids):
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if input_ids[i:i + len(self.bos_id)] == self.bos_id:
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start = i + len(self.bos_id)
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end = start
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while end < len(input_ids):
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if input_ids[end:end + len(self.eos_id)] == self.eos_id:
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break
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end += 1
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for j in range(start, min(end + len(self.eos_id), self.max_length)):
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labels[j] = input_ids[j]
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i = end + len(self.eos_id) if end < len(input_ids) else len(input_ids)
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else:
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i += 1
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return labels
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def __getitem__(self, index):
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sample = self.samples[index]
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prompt = self.create_chat_prompt(sample['conversations'])
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input_ids = self.tokenizer(prompt).input_ids[:self.max_length]
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input_ids += [self.tokenizer.pad_token_id] * (self.max_length - len(input_ids))
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labels = self.generate_labels(input_ids)
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# # === 调试打印 ===
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# print(f"\n--- Sample {index} ---")
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# for i, (x, y) in enumerate(zip(input_ids[:-1], labels[1:])):
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# print(f"{i:3d}: X={self.tokenizer.decode([x])!r:16s} ---> Y={self.tokenizer.decode([input_ids[i+1]])!r:16s} label={y}")
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# # ================
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return torch.tensor(input_ids, dtype=torch.long), torch.tensor(labels, dtype=torch.long)
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class DPODataset(Dataset):
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def __init__(self, file_path, tokenizer, max_length=4096):
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super().__init__()
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self.tokenizer = tokenizer
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self.max_length = max_length
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self.padding = tokenizer.pad_token_id if tokenizer.pad_token_id is not None else 0
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self.bos_id = tokenizer(f'{tokenizer.bos_token}assistant\n', add_special_tokens=False).input_ids
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self.eos_id = tokenizer(f'{tokenizer.eos_token}\n', add_special_tokens=False).input_ids
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self.data = load_dataset('json', data_files=file_path, split='train')
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def __len__(self):
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return len(self.data)
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def __getitem__(self, index):
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item = self.data[index]
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chosen = item['chosen'] # 是一个 list，里面包含若干 {role, content}
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rejected = item['rejected'] # 同上
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chosen_prompt = self.tokenizer.apply_chat_template(
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chosen, tokenize=False, add_generation_prompt=False
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)
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rejected_prompt = self.tokenizer.apply_chat_template(
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rejected, tokenize=False, add_generation_prompt=False
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)
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chosen_encoding = self.tokenizer(
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chosen_prompt, truncation=True, max_length=self.max_length, padding='max_length'
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)
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rejected_encoding = self.tokenizer(
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rejected_prompt, truncation=True, max_length=self.max_length, padding='max_length'
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)
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chosen_input_ids = chosen_encoding['input_ids']
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chosen_loss_mask = self.generate_loss_mask(chosen_input_ids)
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rejected_input_ids = rejected_encoding['input_ids']
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rejected_loss_mask = self.generate_loss_mask(rejected_input_ids)
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x_chosen = torch.tensor(chosen_input_ids[:-1], dtype=torch.long)
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y_chosen = torch.tensor(chosen_input_ids[1:], dtype=torch.long)
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mask_chosen = torch.tensor(chosen_loss_mask[1:], dtype=torch.long)
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x_rejected = torch.tensor(rejected_input_ids[:-1], dtype=torch.long)
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y_rejected = torch.tensor(rejected_input_ids[1:], dtype=torch.long)
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mask_rejected = torch.tensor(rejected_loss_mask[1:], dtype=torch.long)
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return {
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'x_chosen': x_chosen,
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'y_chosen': y_chosen,
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'mask_chosen': mask_chosen,
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'x_rejected': x_rejected,
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'y_rejected': y_rejected,
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'mask_rejected': mask_rejected
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}
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def generate_loss_mask(self, input_ids):
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loss_mask = [0] * len(input_ids)
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i = 0
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while i < len(input_ids):
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if input_ids[i:i + len(self.bos_id)] == self.bos_id:
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start = i + len(self.bos_id)
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end = start
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while end < len(input_ids):
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if input_ids[end:end + len(self.eos_id)] == self.eos_id:
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break
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end += 1
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for j in range(start, min(end + len(self.eos_id), self.max_length)):
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loss_mask[j] = 1
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i = end + len(self.eos_id) if end < len(input_ids) else len(input_ids)
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else:
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i += 1
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return loss_mask
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class RLAIFDataset(Dataset):
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def __init__(self, jsonl_path, tokenizer, max_length=1024):
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super().__init__()
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self.tokenizer = tokenizer
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self.max_length = max_length
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self.samples = load_dataset('json', data_files=jsonl_path, split='train')
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self.bos_id = tokenizer(f'{tokenizer.bos_token}assistant', add_special_tokens=False).input_ids
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self.eos_id = tokenizer(f'{tokenizer.eos_token}', add_special_tokens=False).input_ids
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def __len__(self):
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return len(self.samples)
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def create_chat_prompt(self, conversations):
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messages = []
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answer = ''
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for i, turn in enumerate(conversations):
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role = 'user' if i % 2 == 0 else 'assistant'
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messages.append({"role": role, "content": turn['content']})
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answer = turn['content']
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return self.tokenizer.apply_chat_template(
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messages[:-1],
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tokenize=False,
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add_generation_prompt=True # 这里需要True
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), answer
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def __getitem__(self, index):
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sample = self.samples[index]
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prompt, answer = self.create_chat_prompt(sample['conversations'])
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return {
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'prompt': prompt,
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'answer': answer
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}
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if __name__ == "__main__":
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pass |