part2v3: CPU-only still supported or GPU is now mandatory?

[cluePrints]

Would you be open to a PR allowing CPU-only people to run the code with no changes or that's out of scope and GPU is a prereq?

/content/exp/nb_08.py in <module>()
    205 _m = tensor([0.47, 0.48, 0.45])
    206 _s = tensor([0.29, 0.28, 0.30])
--> 207 norm_imagenette = partial(normalize_chan, mean=_m.cuda(), std=_s.cuda())
    208 
    209 import math

/usr/local/lib/python3.6/dist-packages/torch/cuda/__init__.py in _lazy_init()
    160             "Cannot re-initialize CUDA in forked subprocess. " + msg)
    161     _check_driver()
--> 162     torch._C._cuda_init()
    163     _cudart = _load_cudart()
    164     _cudart.cudaGetErrorName.restype = ctypes.c_char_p

RuntimeError: cuda runtime error (38) : no CUDA-capable device is detected at /pytorch/aten/src/THC/THCGeneral.cpp:51

[jph00]

Yes, we could replace that with .to(device) and have a place in the notebook to set the device.