Values smaller than 1e-6 are due to the limited floating point precision, so you shouldn’t worry about it.
Unrelated to this, but Variables are deprecated since PyTorch 0.4.0, so you can just use tensors now.
Also, I wouldn’t recommend to use .data anymore, as this might have some negative side effects, since Autograd cannot track the changes made to the .data attribute. This is not really important in your current code, but might lead to some issues in the future.