微调Mistral 7B模型时遇ValueError参数冲突错误求助

这个错误的核心是重复配置了4bit加载参数：你既在BitsAndBytesConfig实例里设置了load_in_4bit=True，又在AutoModelForCausalLM.from_pretrained()中单独传入了load_in_4bit=True——这两个参数是互斥的，只能二选一。

两种可行的修改方案 #

方案一：保留quantization_config（推荐）

直接移除from_pretrained中的load_in_4bit=True参数，用BitsAndBytesConfig统一管理量化配置，修改后的代码如下：

# Load base model(Mistral 7B)
bnb_config = BitsAndBytesConfig(  
    load_in_4bit= True,
    bnb_4bit_quant_type= "nf4",
    bnb_4bit_compute_dtype= torch.bfloat16,
    bnb_4bit_use_double_quant= False,
)
model = AutoModelForCausalLM.from_pretrained(
        base_model,
        quantization_config=bnb_config,
        torch_dtype=torch.bfloat16,
        device_map="auto",
        trust_remote_code=True,
)
model.config.use_cache = False # silence the warnings. Please re-enable for inference!
model.config.pretraining_tp = 1
model.gradient_checkpointing_enable()

# Load tokenizer
tokenizer = AutoTokenizer.from_pretrained(base_model, trust_remote_code=True)
tokenizer.padding_side = 'right'
tokenizer.pad_token = tokenizer.eos_token
tokenizer.add_eos_token = True
tokenizer.add_bos_token, tokenizer.add_eos_token

方案二：直接在from_pretrained中传量化参数

如果你不想用BitsAndBytesConfig，可以删掉相关配置代码，直接把量化参数传入from_pretrained：

# Load base model(Mistral 7B)
model = AutoModelForCausalLM.from_pretrained(
        base_model,
        load_in_4bit=True,
        bnb_4bit_quant_type= "nf4",
        bnb_4bit_compute_dtype= torch.bfloat16,
        bnb_4bit_use_double_quant= False,
        torch_dtype=torch.bfloat16,
        device_map="auto",
        trust_remote_code=True,
)
model.config.use_cache = False # silence the warnings. Please re-enable for inference!
model.config.pretraining_tp = 1
model.gradient_checkpointing_enable()

# Load tokenizer
tokenizer = AutoTokenizer.from_pretrained(base_model, trust_remote_code=True)
tokenizer.padding_side = 'right'
tokenizer.pad_token = tokenizer.eos_token
tokenizer.add_eos_token = True
tokenizer.add_bos_token, tokenizer.add_eos_token

注意：方案一的配置方式更清晰，后续修改量化参数时只需调整bnb_config即可，更便于维护。

内容的提问来源于stack exchange，提问作者Jyoti yadav