Attempting to deserialize object on a CUDA device but torch.cuda.is_available() is False.

I’m using ray to predict large number of files.

The pytorch model is trained on GPU. The machine has one GPU. If I run torch.cuda.is_available(), it returns True.

But I still go the error:

File "python/ray/_raylet.pyx", line 410, in ray._raylet.execute_task
  File "python/ray/_raylet.pyx", line 427, in ray._raylet.execute_task
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/ray/serialization.py", line 312, in deserialize_objects
    self._deserialize_object(data, metadata, object_id))
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/ray/serialization.py", line 252, in _deserialize_object
    return self._deserialize_msgpack_data(data, metadata)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/ray/serialization.py", line 233, in _deserialize_msgpack_data
    python_objects = self._deserialize_pickle5_data(pickle5_data)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/ray/serialization.py", line 221, in _deserialize_pickle5_data
    obj = pickle.loads(in_band)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/storage.py", line 142, in _load_from_bytes
    return torch.load(io.BytesIO(b))
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 585, in load
    return _legacy_load(opened_file, map_location, pickle_module, **pickle_load_args)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 765, in _legacy_load
    result = unpickler.load()
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 721, in persistent_load
    deserialized_objects[root_key] = restore_location(obj, location)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 174, in default_restore_location
    result = fn(storage, location)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 150, in _cuda_deserialize
    device = validate_cuda_device(location)
  File "/home/yujl/anaconda3/lib/python3.7/site-packages/torch/serialization.py", line 134, in validate_cuda_device
    raise RuntimeError('Attempting to deserialize object on a CUDA '
RuntimeError: Attempting to deserialize object on a CUDA device but torch.cuda.is_available() is False. If you are running on a CPU-only machine, please use torch.load with map_location=torch.device('cpu') to map your storages to the CPU.

How do I use the model on GPU?