andreabosisio

Hi @Karbo123 ! I'm also trying to implement the inversion (but on DDIM) and am also a bit confused about the indexing. Did you manage to find a simple workaround...

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> ### Q1 > > I'm sorry, but I didn't quite understand your question. Could you please provide more details? `self.sqrt_alphas_cumprod_prev` is indexed for DDPM (i.e., `t - t_prev =...

Yes, I'm aware of that, but the issue I'm pointing out is this: imagine the current timestep is `step=500`, and according to the DDIM schedule, the previous timestep is `t_prev=450`....

An easy way to handle the `step=0` case is as they do in here https://github.com/huggingface/diffusers/blob/560fb5f4d65b8593c13e4be50a59b1fd9c2d9992/src/diffusers/schedulers/scheduling_ddim.py#L406. Anyway, I think the issue is there also for all the other steps, right? I've...