Fix bug: RuntimeError: set_sizes_contiguous is not allowed on Tensor …

[gachiemchiep]

When i tried your source with newer version of pytorch (1.4) the following error happened.

Traceback (most recent call last):
  File "test_net.py", line 276, in <module>
    im_data.data.resize_(data[0].size()).copy_(data[0])
RuntimeError: set_sizes_contiguous is not allowed on a Tensor created from .data or .detach().
If your intent is to change the metadata of a Tensor (such as sizes / strides / storage / storage_offset)
without autograd tracking the change, remove the .data / .detach() call and wrap the change in a `with torch.no_grad():` block.
For example, change:
    x.data.set_(y)
to:
    with torch.no_grad():
        x.set_(y)

So i add a pr to fix it.