"""Whether to echo the prompt."""
    stop: Optional[List[str]] = []
    """A list of strings to stop generation when encountered."""
    repeat_penalty: Optional[float] = 1.1
    """The penalty to apply to repeated tokens."""
    top_k: Optional[int] = 40
    """The top-k value to use for sampling."""
    last_n_tokens_size: Optional[int] = 64
    """The number of tokens to look back when applying the repeat_penalty."""
    use_mmap: Optional[bool] = True
    """Whether to keep the model loaded in RAM"""
    streaming: bool = True
    """Whether to stream the results, token by token."""
    @root_validator()
    def validate_environment(cls, values: Dict) -> Dict:
        """Validate that llama-cpp-python library is installed."""
        model_path = values["model_path"]
        model_param_names = [
            "lora_path",
            "lora_base",
            "n_ctx",
            "n_parts",
            "seed",
            "f16_kv",
            "logits_all",
            "vocab_only",
            "use_mlock",
            "n_threads",
            "n_batch",
            "use_mmap",
            "last_n_tokens_size",
        ]
        model_params = {k: values[k] for k in model_param_names}
        # For backwards compatibility, only include if non-null.
        if values["n_gpu_layers"] is not None:
            model_params["n_gpu_layers"] = values["n_gpu_layers"]
        try:
            from llama_cpp import Llama
            values["client"] = Llama(model_path, **model_params)
        except ImportError:
            raise ModuleNotFoundError(
rtdocs_stable/api.python.langchain.com/en/stable/_modules/langchain/llms/llamacpp.html