小编点评

**代码步骤：** 1. 下载并安装 Transformers 库。 2. 创建一个名为 `TextDataset` 的类，它继承 `Dataset` 类。 3. 在 `__init__` 方法中，初始化数据集和加载模型文件。 4. 在 `train` 方法中，定义训练模型的训练循环。 5. 在 `main` 方法中，创建数据集和 DataLoader，并初始化模型和优化器。 6. 在训练过程中，循环 through dataloader 的批次，并执行训练操作。 7. 在训练结束后，保存微调后的模型和 tokenizer。 8. 保存模型和 tokenizer 的路径。 9. 在主程序中，选择设备、加载模型和训练模型。

正文

为了AIGC的学习，我做了一个基于Transformer Models模型完成GPT2的学生AIGC学习训练模型，指在训练模型中学习编程AI。

在编程之前需要准备一些文件：

首先，先win+R打开运行框，输入：PowerShell后

输入：

pip install -U huggingface_hub

下载完成后，指定我们的环境变量：

$env:HF_ENDPOINT = "https://hf-mirror.com"

然后下载模型：

huggingface-cli download --resume-download gpt2 --local-dir "D:\Pythonxiangmu\PythonandAI\Transformer Models\gpt-2"

这边我的目录是我要下载的工程目录地址

然后下载数据量：

huggingface-cli download --repo-type dataset --resume-download wikitext --local-dir "D:\Pythonxiangmu\PythonandAI\Transformer Models\gpt-2"

这边我的目录是我要下载的工程目录地址

所以两个地址记得更改成自己的工程目录下（建议放在创建一个名为gpt-2的文件夹）

在PowerShell中下载完这些后，可以开始我们的代码啦

import torch
from torch.utils.data import Dataset, DataLoader
from transformers import (
    AutoTokenizer,
    AutoModelForCausalLM,
    AdamW,
    get_linear_schedule_with_warmup,
    set_seed,
)
from torch.optim import AdamW

# 设置随机种子以确保结果可复现
set_seed(42)


class TextDataset(Dataset):
    def __init__(self, tokenizer, texts, block_size=128):
        self.tokenizer = tokenizer
        self.examples = [
            self.tokenizer(text, return_tensors="pt", padding='max_length', truncation=True, max_length=block_size) for
            text
            in texts]
        # 在tokenizer初始化后，确保unk_token已设置
        print(f"Tokenizer's unk_token: {self.tokenizer.unk_token}, unk_token_id: {self.tokenizer.unk_token_id}")

    def __len__(self):
        return len(self.examples)

    def __getitem__(self, i):
        item = self.examples[i]
        # 替换所有不在vocab中的token为unk_token_id
        for key in item.keys():
            item[key] = torch.where(item[key] >= self.tokenizer.vocab_size, self.tokenizer.unk_token_id, item[key])
        return item


def train(model, dataloader, optimizer, scheduler, de, tokenizer):
    model.train()
    for batch in dataloader:
        input_ids = batch['input_ids'].to(de)
        # 添加日志输出检查input_ids
        if torch.any(input_ids >= model.config.vocab_size):
            print("Warning: Some input IDs are outside the model's vocabulary.")
            print(f"Max input ID: {input_ids.max()}, Vocabulary Size: {model.config.vocab_size}")

        attention_mask = batch['attention_mask'].to(de)
        labels = input_ids.clone()
        labels[labels[:, :] == tokenizer.pad_token_id] = -100

        outputs = model(input_ids=input_ids, attention_mask=attention_mask, labels=labels)
        loss = outputs.loss
        loss.backward()

        optimizer.step()
        scheduler.step()
        optimizer.zero_grad()


def main():
    local_model_path = "D:/Pythonxiangmu/PythonandAI/Transformer Models/gpt-2"
    tokenizer = AutoTokenizer.from_pretrained(local_model_path)

    # 确保pad_token已经存在于tokenizer中，对于GPT-2，它通常自带pad_token
    if tokenizer.pad_token is None:
        special_tokens_dict = {'pad_token': '[PAD]'}
        tokenizer.add_special_tokens(special_tokens_dict)
        model = AutoModelForCausalLM.from_pretrained(local_model_path, pad_token_id=tokenizer.pad_token_id)
    else:
        model = AutoModelForCausalLM.from_pretrained(local_model_path)

    model.to(device)

    train_texts = [
        "The quick brown fox jumps over the lazy dog.",
        "In the midst of chaos, there is also opportunity.",
        "To be or not to be, that is the question.",
        "Artificial intelligence will reshape our future.",
        "Every day is a new opportunity to learn something.",
        "Python programming enhances problem-solving skills.",
        "The night sky sparkles with countless stars.",
        "Music is the universal language of mankind.",
        "Exploring the depths of the ocean reveals hidden wonders.",
        "A healthy mind resides in a healthy body.",
        "Sustainability is key for our planet's survival.",
        "Laughter is the shortest distance between two people.",
        "Virtual reality opens doors to immersive experiences.",
        "The early morning sun brings hope and vitality.",
        "Books are portals to different worlds and minds.",
        "Innovation distinguishes between a leader and a follower.",
        "Nature's beauty can be found in the simplest things.",
        "Continuous learning fuels personal growth.",
        "The internet connects the world like never before."
        # 更多训练文本...
    ]

    dataset = TextDataset(tokenizer, train_texts, block_size=128)
    dataloader = DataLoader(dataset, batch_size=4, shuffle=True)

    optimizer = AdamW(model.parameters(), lr=5e-5)
    total_steps = len(dataloader) * 5  # 假设训练5个epoch
    scheduler = get_linear_schedule_with_warmup(optimizer, num_warmup_steps=0, num_training_steps=total_steps)

    for epoch in range(5):  # 训练5个epoch
        train(model, dataloader, optimizer, scheduler, device, tokenizer)  # 使用正确的变量名dataloader并传递tokenizer

    # 保存微调后的模型
    model.save_pretrained("path/to/save/fine-tuned_model")
    tokenizer.save_pretrained("path/to/save/fine-tuned_tokenizer")


if __name__ == "__main__":
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    main()

这个代码只训练了5个epoch，有一些实例文本，记得调成直接的路径后，运行即可啦。

如果有什么问题可以随时在评论区或者是发个人邮箱：linyuanda@linyuanda.com