Support views batch for panorama (#3632)

* support views batch for panorama

* add entry for the new argument

* format entry for the new argument

* add view_batch_size test

* fix batch test and a boundary condition

* add more docstrings

* fix a typos

* fix typos

* add: entry to the doc about view_batch_size.

* Revert "add: entry to the doc about view_batch_size."

This reverts commit a36aeaa9edf9b662d09bbfd6e18cbc556ed38187.

* add a tip on .

---------
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

docs/source/en/api/pipelines/panorama.mdx

@@ -52,6 +52,14 @@ image = pipe(prompt).images[0]
 image.save("dolomites.png")
 ```
 
+<Tip>
+
+While calling this pipeline, it's possible to specify the `view_batch_size` to have a >1 value. 
+For some GPUs with high performance, higher a `view_batch_size`, can speedup the generation
+and increase the VRAM usage.
+
+</Tip>
+
 ## StableDiffusionPanoramaPipeline
 [[autodoc]] StableDiffusionPanoramaPipeline
 	- __call__

src/diffusers/pipelines/stable_diffusion/pipeline_stable_diffusion_panorama.py

@@ -451,10 +451,11 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
 
     def get_views(self, panorama_height, panorama_width, window_size=64, stride=8):
         # Here, we define the mappings F_i (see Eq. 7 in the MultiDiffusion paper https://arxiv.org/abs/2302.08113)
+        # if panorama's height/width < window_size, num_blocks of height/width should return 1
         panorama_height /= 8
         panorama_width /= 8
-        num_blocks_height = (panorama_height - window_size) // stride + 1
-        num_blocks_width = (panorama_width - window_size) // stride + 1
+        num_blocks_height = (panorama_height - window_size) // stride + 1 if panorama_height > window_size else 1
+        num_blocks_width = (panorama_width - window_size) // stride + 1 if panorama_height > window_size else 1
         total_num_blocks = int(num_blocks_height * num_blocks_width)
         views = []
         for i in range(total_num_blocks):
@@ -474,6 +475,7 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
         width: Optional[int] = 2048,
         num_inference_steps: int = 50,
         guidance_scale: float = 7.5,
+        view_batch_size: int = 1,
         negative_prompt: Optional[Union[str, List[str]]] = None,
         num_images_per_prompt: Optional[int] = 1,
         eta: float = 0.0,
@@ -508,6 +510,9 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
                 Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale >
                 1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`,
                 usually at the expense of lower image quality.
+            view_batch_size (`int`, *optional*, defaults to 1):
+                The batch size to denoise splited views. For some GPUs with high performance, higher view batch size
+                can speedup the generation and increase the VRAM usage.
             negative_prompt (`str` or `List[str]`, *optional*):
                 The prompt or prompts not to guide the image generation. If not defined, one has to pass
                 `negative_prompt_embeds` instead. Ignored when not using guidance (i.e., ignored if `guidance_scale` is
@@ -609,8 +614,11 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
         )
 
         # 6. Define panorama grid and initialize views for synthesis.
+        # prepare batch grid
         views = self.get_views(height, width)
-        views_scheduler_status = [copy.deepcopy(self.scheduler.__dict__)] * len(views)
+        views_batch = [views[i : i + view_batch_size] for i in range(0, len(views), view_batch_size)]
+        views_scheduler_status = [copy.deepcopy(self.scheduler.__dict__)] * len(views_batch)
+
         count = torch.zeros_like(latents)
         value = torch.zeros_like(latents)
 
@@ -631,42 +639,55 @@ class StableDiffusionPanoramaPipeline(DiffusionPipeline, TextualInversionLoaderM
                 # denoised (latent) crops are then averaged to produce the final latent
                 # for the current timestep via MultiDiffusion. Please see Sec. 4.1 in the
                 # MultiDiffusion paper for more details: https://arxiv.org/abs/2302.08113
-                for j, (h_start, h_end, w_start, w_end) in enumerate(views):
+                # Batch views denoise
+                for j, batch_view in enumerate(views_batch):
+                    vb_size = len(batch_view)
                     # get the latents corresponding to the current view coordinates
-                    latents_for_view = latents[:, :, h_start:h_end, w_start:w_end]
+                    latents_for_view = torch.cat(
+                        [latents[:, :, h_start:h_end, w_start:w_end] for h_start, h_end, w_start, w_end in batch_view]
+                    )
 
                     # rematch block's scheduler status
                     self.scheduler.__dict__.update(views_scheduler_status[j])
 
                     # expand the latents if we are doing classifier free guidance
                     latent_model_input = (
-                        torch.cat([latents_for_view] * 2) if do_classifier_free_guidance else latents_for_view
+                        latents_for_view.repeat_interleave(2, dim=0)
+                        if do_classifier_free_guidance
+                        else latents_for_view
                     )
                     latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
 
+                    # repeat prompt_embeds for batch
+                    prompt_embeds_input = torch.cat([prompt_embeds] * vb_size)
+
                     # predict the noise residual
                     noise_pred = self.unet(
                         latent_model_input,
                         t,
-                        encoder_hidden_states=prompt_embeds,
+                        encoder_hidden_states=prompt_embeds_input,
                         cross_attention_kwargs=cross_attention_kwargs,
                     ).sample
 
                     # perform guidance
                     if do_classifier_free_guidance:
-                        noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
+                        noise_pred_uncond, noise_pred_text = noise_pred[::2], noise_pred[1::2]
                         noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
 
                     # compute the previous noisy sample x_t -> x_t-1
-                    latents_view_denoised = self.scheduler.step(
+                    latents_denoised_batch = self.scheduler.step(
                         noise_pred, t, latents_for_view, **extra_step_kwargs
                     ).prev_sample
 
                     # save views scheduler status after sample
                     views_scheduler_status[j] = copy.deepcopy(self.scheduler.__dict__)
 
-                    value[:, :, h_start:h_end, w_start:w_end] += latents_view_denoised
-                    count[:, :, h_start:h_end, w_start:w_end] += 1
+                    # extract value from batch
+                    for latents_view_denoised, (h_start, h_end, w_start, w_end) in zip(
+                        latents_denoised_batch.chunk(vb_size), batch_view
+                    ):
+                        value[:, :, h_start:h_end, w_start:w_end] += latents_view_denoised
+                        count[:, :, h_start:h_end, w_start:w_end] += 1
 
                 # take the MultiDiffusion step. Eq. 5 in MultiDiffusion paper: https://arxiv.org/abs/2302.08113
                 latents = torch.where(count > 0, value / count, value)

tests/pipelines/stable_diffusion/test_stable_diffusion_panorama.py

@@ -131,7 +131,7 @@ class StableDiffusionPanoramaPipelineFastTests(PipelineLatentTesterMixin, Pipeli
 
     # override to speed the overall test timing up.
     def test_inference_batch_single_identical(self):
-        super().test_inference_batch_single_identical(batch_size=2, expected_max_diff=3e-3)
+        super().test_inference_batch_single_identical(batch_size=2, expected_max_diff=3.25e-3)
 
     def test_stable_diffusion_panorama_negative_prompt(self):
         device = "cpu"  # ensure determinism for the device-dependent torch.Generator
@@ -152,6 +152,24 @@ class StableDiffusionPanoramaPipelineFastTests(PipelineLatentTesterMixin, Pipeli
 
         assert np.abs(image_slice.flatten() - expected_slice).max() < 1e-2
 
+    def test_stable_diffusion_panorama_views_batch(self):
+        device = "cpu"  # ensure determinism for the device-dependent torch.Generator
+        components = self.get_dummy_components()
+        sd_pipe = StableDiffusionPanoramaPipeline(**components)
+        sd_pipe = sd_pipe.to(device)
+        sd_pipe.set_progress_bar_config(disable=None)
+
+        inputs = self.get_dummy_inputs(device)
+        output = sd_pipe(**inputs, view_batch_size=2)
+        image = output.images
+        image_slice = image[0, -3:, -3:, -1]
+
+        assert image.shape == (1, 64, 64, 3)
+
+        expected_slice = np.array([0.6187, 0.5375, 0.4915, 0.4136, 0.4114, 0.4563, 0.5128, 0.4976, 0.4757])
+
+        assert np.abs(image_slice.flatten() - expected_slice).max() < 1e-2
+
     def test_stable_diffusion_panorama_euler(self):
         device = "cpu"  # ensure determinism for the device-dependent torch.Generator
         components = self.get_dummy_components()