Allow compatibility with latest torch (torch 18.1)

[colleenjg]

I've been running the codebase with one of the latest torch versions (18.1) with only 3 small compatibility problems coming up, per my usage.

dpc/main.py, lines 215 and 267:

• target_flattened raises 2 errors:
  • It is not automatically placed on cuda when created, which leads to an error when criterion() is called.
    => Solution: explicitly place on cuda before the call to criterion()
  • It is a boolean tensor, and argmax() now raises an error with boolean tensors.
    => Solution: convert to int before calling argmax().

utils/utils.py, line 53:

• .view(-1) in correct_k = correct[:k].view(-1).float().sum(0) raises a runtime error (message: view size is not compatible with input tensor's size and stride...)
  => Solution: either use .reshape(-1) or make a call to .contiguous() before using .view(-1).

The bugs are quite minor with easy solutions that shouldn't cause a problem for previous torch versions. I am happy to make a pull request if helpful!

Thanks! :)

[TengdaHan]

Ahh, thank you for the checking and I am very grateful if you can make a pull request!

[colleenjg]

Great! Just made the above pull request.