Create pipeline.py

pipeline.py

@@ -0,0 +1,83 @@
+from typing import List, Optional, Tuple, Union
+
+import torch
+
+from diffusers.schedulers import DDIMScheduler
+from diffusers.utils.torch_utils import randn_tensor
+from diffusers.pipelines.pipeline_utils import DiffusionPipeline, ImagePipelineOutput
+
+
+class DDIMPipelineCustom(DiffusionPipeline):
+    model_cpu_offload_seq = "unet"
+
+    def __init__(self, unet, scheduler):
+        super().__init__()
+
+        # make sure scheduler can always be converted to DDIM
+        scheduler = DDIMScheduler.from_config(scheduler.config)
+
+        self.register_modules(unet=unet, scheduler=scheduler)
+
+    @torch.no_grad()
+    def __call__(
+        self,
+        condition = None,
+        guidance: float = 1,
+        batch_size: int = 1,
+        generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None,
+        eta: float = 0.0,
+        num_inference_steps: int = 50,
+        use_clipped_model_output: Optional[bool] = None,
+        output_type: Optional[str] = "pil",
+        return_dict: bool = True,
+    ) -> Union[ImagePipelineOutput, Tuple]:
+        # Sample gaussian noise to begin loop
+        if isinstance(self.unet.config.sample_size, int):
+            image_shape = (
+                batch_size,
+                self.unet.config.in_channels,
+                self.unet.config.sample_size,
+                self.unet.config.sample_size,
+            )
+        else:
+            image_shape = (batch_size, self.unet.config.in_channels, *self.unet.config.sample_size)
+
+        if isinstance(generator, list) and len(generator) != batch_size:
+            raise ValueError(
+                f"You have passed a list of generators of length {len(generator)}, but requested an effective batch"
+                f" size of {batch_size}. Make sure the batch size matches the length of the generators."
+            )
+
+        image = randn_tensor(image_shape, generator=generator, device=self._execution_device, dtype=self.unet.dtype)
+
+        # set step values
+        self.scheduler.set_timesteps(num_inference_steps)
+
+        for t in self.progress_bar(self.scheduler.timesteps):
+            # 1. predict noise model_output
+            uncond = -torch.ones(batch_size, device=self.device)
+
+            if condition is not None:
+              model_output_uncond = self.unet(image, t, uncond).sample
+              model_output_cond = self.unet(image, t, condition).sample
+
+              model_output = torch.lerp(model_output_uncond, model_output_cond, guidance)
+            else:
+              model_output = self.unet(image, t, uncond).sample
+
+            # 2. predict previous mean of image x_t-1 and add variance depending on eta
+            # eta corresponds to η in paper and should be between [0, 1]
+            # do x_t -> x_t-1
+            image = self.scheduler.step(
+                model_output, t, image, eta=eta, use_clipped_model_output=use_clipped_model_output, generator=generator
+            ).prev_sample
+
+        image = (image / 2 + 0.5).clamp(0, 1)
+        image = image.cpu().permute(0, 2, 3, 1).numpy()
+        if output_type == "pil":
+            image = self.numpy_to_pil(image)
+
+        if not return_dict:
+            return (image,)
+
+        return ImagePipelineOutput(images=image)