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vllm.model_executor.model_loader.dummy_loader

DummyModelLoader

Bases: BaseModelLoader

Model loader that will set model weights to random values.

Source code in vllm/model_executor/model_loader/dummy_loader.py 
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class DummyModelLoader(BaseModelLoader):
    """Model loader that will set model weights to random values."""

    def __init__(self, load_config: LoadConfig):
        super().__init__(load_config)
        if load_config.model_loader_extra_config:
            raise ValueError(f"Model loader extra config is not supported for "
                             f"load format {load_config.load_format}")

    def download_model(self, model_config: ModelConfig) -> None:
        pass  # Nothing to download

    def load_model(self, vllm_config: VllmConfig,
                   model_config: ModelConfig) -> nn.Module:
        device_config = vllm_config.device_config
        target_device = torch.device(device_config.device)
        with set_default_torch_dtype(model_config.dtype):
            with target_device:
                model = initialize_model(vllm_config=vllm_config)
            # NOTE(woosuk): For accurate performance evaluation, we assign
            # random values to the weights.
            initialize_dummy_weights(model)

            process_weights_after_loading(model, model_config, target_device)
        return model.eval()

__init__ 

__init__(load_config: LoadConfig)
Source code in vllm/model_executor/model_loader/dummy_loader.py 
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def __init__(self, load_config: LoadConfig):
    super().__init__(load_config)
    if load_config.model_loader_extra_config:
        raise ValueError(f"Model loader extra config is not supported for "
                         f"load format {load_config.load_format}")

download_model 

download_model(model_config: ModelConfig) -> None
Source code in vllm/model_executor/model_loader/dummy_loader.py 
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def download_model(self, model_config: ModelConfig) -> None:
    pass  # Nothing to download

load_model 

load_model(
    vllm_config: VllmConfig, model_config: ModelConfig
) -> Module
Source code in vllm/model_executor/model_loader/dummy_loader.py 
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def load_model(self, vllm_config: VllmConfig,
               model_config: ModelConfig) -> nn.Module:
    device_config = vllm_config.device_config
    target_device = torch.device(device_config.device)
    with set_default_torch_dtype(model_config.dtype):
        with target_device:
            model = initialize_model(vllm_config=vllm_config)
        # NOTE(woosuk): For accurate performance evaluation, we assign
        # random values to the weights.
        initialize_dummy_weights(model)

        process_weights_after_loading(model, model_config, target_device)
    return model.eval()