Fix cuda compilation

[EmilyBourne]

Merge Request - GuideLine Checklist

Guideline to check code before resolve WIP and approval, respectively.
As many checkboxes as possible should be ticked.

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• There is at least one issue associated with the pull request.
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If functions were changed or functionality was added:

• Tests for new functionality has been added
• A local test was succesful

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Checks by code reviewer(s):

• Is the code clean of development artifacts e.g., unnecessary comments, prints, ...
• The ticket goals for each associated issue are reached or problems are clearly addressed (i.e., a new issue was introduced).
• There are appropriate unit tests and they pass.
• The git history is clean and linearized for the merge request. All reviewers should squash commits and write a simple and meaningful commit message.
• Coverage report for new code is acceptable.
• No large data files have been added to the repository. Maximum size for files should be of the order of KB not MB. In particular avoid adding of pdf, word, or other files that cannot be change-tracked correctly by git.

[EmilyBourne]

@julianlitz This PR fixes the cuda compilation in #256 but it doesn't change the logic. The tests are already failing in #256

[julianlitz]

@EmilyBourne Alright I will fix that

[julianlitz]

@EmilyBourne Claude found the issue. It is now hopefully fixed

[julianlitz]

Oh you already added these fence() calls... 🫠