Expose schedulers

[osanseviero]

Right now this gives ModuleNotFoundError: No module named 'diffusers.optimization' error.

from diffusers.optimization import get_scheduler

Do we want to expose all schedulers or do we want to force people to use get_scheduler to get them?

[patrickvonplaten]

@anton-l - could you take a look here? :-)

[HuggingFaceDocBuilderDev]

The documentation is not available anymore as the PR was closed or merged.

[anton-l]

I think it's ok to expose them for now, thanks for the fix! Although I'd like to make the naming less confusing between these and the noise schedulers.

Or maybe just replace them with https://pytorch.org/docs/stable/generated/torch.optim.lr_scheduler.OneCycleLR.html and others, since they've already caught up with the ones we have in 'transformers` and here in terms of flexibility.

[patrickvonplaten]

Very much agree here with @anton-l, let's please make sure from the very beginning that learning rate schedulers are never confused with noise schedulers.
When we talk about "schedulers" in diffusers we should always assume that we refer to the noise schedulers under src/diffusers/schedulers". I would strongly suggest to open a PR to add a lr_ prefix (for learning rate) to all learning rate schedulers. What do you think @anton-l ? E.g. the function get_scheduler should be renamed to get_lr_scheduler etc..