No randomness is added during the sampling process?

[PANG-98]

Hey fellows, really good work and thanks for sharing the code. However, I've got a question about the sampling process. It seems like no randomness is added during the sampling process, like the z in the following equation.

I've checked the code and it seems like add_noise function defined in DPM_Solver class has never been used. Why is the case? Could you very kindly explain this? Thanks!

[LuChengTHU]

Because DPM-Solver is an ODE-based solver so it does not add noises at the intermediate steps. I also implemented SDE-based DPM-Solver here: https://huggingface.co/docs/diffusers/en/api/schedulers/multistep_dpm_solver

[PANG-98]

Because DPM-Solver is an ODE-based solver so it does not add noises at the intermediate steps. I also implemented SDE-based DPM-Solver here: https://huggingface.co/docs/diffusers/en/api/schedulers/multistep_dpm_solver

Thanks for your reply. Any preference for these two implementation? which one is more accurate?