[model] add DiffMG model

vegetable-a commented 1 year ago

Description

Please feel free to remove inapplicable items for your PR.

[x] The PR title starts with [$CATEGORY] (such as [NN], [Model], [Doc], [Feature]])
[x] Changes are complete (i.e. I finished coding on this PR)
[x] All changes have test coverage
[x] Code is well-documented
[x] To the best of my knowledge, examples are either not affected by this change, or have been fixed to be compatible with this change
[x] Related issue is referred in this PR
[x] If the PR is for a new model/paper, I've updated the example index here.

dddg617 commented 1 year ago

Also, I think it is better to create a dataset module to preprocess the dataset instead of putting this into the trainerflow.

dddg617 commented 1 year ago

Do you have any documents about your model? Please create a document in the openhgnn/output/ and give a model performance.