Fix bugs in influence

[Xuzzo]

Description

This PR closes #357, #356

Changes

• Moves break condition up in cg
• adds device in identity_tensor

Checklist

• Wrote Unit tests (if necessary)
• Updated Documentation (if necessary)
• Updated Changelog
• If notebooks were added/changed, added boilerplate cells are tagged with "nbsphinx":"hidden"

[murong-xu]

I checked, everything fine, thanks!

[mdbenito]

@Xuzzo Can you get the checks to pass and merge this? We have #365 almost ready to be merged and it will be affected by whatever you do here. Kristof will then proceed to rewrite some interfaces and should be able to start from code that works ok.

[AnesBenmerzoug]

@Xuzzo The docs failure is due to a missing appendix section in the influence imagenet notebook.

@mdbenito The test failure comes from somewhere else though (It also appears in the develop branch, which is weird). I will try to fix that in a separate PR.

[mdbenito]

@Xuzzo The docs failure is due to a missing appendix section in the influence imagenet notebook.

@mdbenito The test failure comes from somewhere else though (It also appears in the develop branch, which is weird). I will try to fix that in a separate PR.

I think @schroedk has suffered the issue as well in #365

[mdbenito]

@Xuzzo In the future, please follow the branch naming conventions!