@colesbury
With the last pytorch-nightly update the errors are gone.
(fastai) marco@phenom:~/MachineLearning$ python
Python 3.7.0 (default, Jun 28 2018, 13:15:42) 
[GCC 7.2.0] :: Anaconda, Inc. on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import torch
>>> torch.__version__
'1.0.0.dev20181010'
>>> torch.cuda.is_available()
True
>>> torch.tensor([1.,2.]).cuda()
tensor([1., 2.], device='cuda:0')
>>>

Thanks for your help.