Integrating a Tailored Diffusion U-Net Model into Generative Model Application

[dongyang0122]

Fixes #7858.

Integrating a tailored diffusion U-Net model into the generative model application to improve the production of high-dimensional 3D images, specifically sized at 512 x 512 x 512.

A few sentences describing the changes proposed in this pull request.

Types of changes

• [x] Non-breaking change (fix or new feature that would not break existing functionality).
• [ ] Breaking change (fix or new feature that would cause existing functionality to change).
• [ ] New tests added to cover the changes.
• [ ] Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• [ ] Quick tests passed locally by running ./runtests.sh --quick --unittests --disttests.
• [ ] In-line docstrings updated.
• [ ] Documentation updated, tested make html command in the docs/ folder.

[dongyang0122]

@KumoLiu @Nic-Ma @ericspod I am not clear how to pass these failed checks. Please share your suggestion. Thanks.