Types of changes

The backpropagation is not working in gromov_wasserstein2 if the given tensors are located on a GPU. This is due to the fact that part of the computation is performed with numpy and the device was forgotten when casting back to torch.

Motivation and context / Related issue

Resolves #351

How has this been tested (if it applies)

PR checklist

• I have read the CONTRIBUTING document.
• The documentation is up-to-date with the changes I made (check build artifacts).
• All tests passed, and additional code has been covered with new tests.
• I have added the PR and Issue fix to the RELEASES.md file.