first convert the model output to the
corresponding type to match the algorithm.
Note that the algorithm type and the model type is decoupled. That is to say, we can use either DPM-Solver or
DPM-Solver++ for both noise prediction model and data prediction model.

dpm_solver_first_order_update

<
source
>
(
model_output: FloatTensor
timestep: int
prev_timestep: int
sample: FloatTensor

)
→
torch.FloatTensor

Parameters 

model_output (torch.Floa