[Community] One step unet (huggingface#840)

Author: patrickvonplaten

examples/community/README.md

@@ -5,3 +5,4 @@
 | Example   |      Description      |      Author      |    Colab  |
 |:----------|:----------------------|:-----------------|----------:|
 | CLIP Guided Stable Diffusion | Doing CLIP guidance for text to image generation with Stable Diffusion| [Suraj Patil](https://github.com/patil-suraj/) | [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/notebooks/blob/main/diffusers/CLIP_Guided_Stable_diffusion_with_diffusers.ipynb) |
+| One Step U-Net (Dummy) | [Patrick von Platen](https://github.com/patrickvonplaten/) | - |

examples/community/one_step_unet.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+import torch
+
+from diffusers import DiffusionPipeline
+
+
+class UnetSchedulerOneForwardPipeline(DiffusionPipeline):
+    def __init__(self, unet, scheduler):
+        super().__init__()
+
+        self.register_modules(unet=unet, scheduler=scheduler)
+
+    def __call__(self):
+        image = torch.randn(
+            (1, self.unet.in_channels, self.unet.sample_size, self.unet.sample_size),
+        )
+        timestep = 1
+
+        model_output = self.unet(image, timestep).sample
+        scheduler_output = self.scheduler.step(model_output, timestep, image).prev_sample
+
+        return scheduler_output