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update the clip guided PR according to the new API (#751)

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Suraj Patil
2022-10-06 15:43:48 +02:00
committed by GitHub
parent df9c070174
commit 3383f77441
1 changed files with 27 additions and 23 deletions
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50
examples/community/clip_guided_stable_diffusion.py
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@@ -175,6 +175,7 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
width: Optional[int] = 512,
num_inference_steps: Optional[int] = 50,
guidance_scale: Optional[float] = 7.5,
num_images_per_prompt: Optional[int] = 1,
clip_guidance_scale: Optional[float] = 100,
clip_prompt: Optional[Union[str, List[str]]] = None,
num_cutouts: Optional[int] = 4,
@@ -203,6 +204,8 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
return_tensors="pt",
)
text_embeddings = self.text_encoder(text_input.input_ids.to(self.device))[0]
# duplicate text embeddings for each generation per prompt
text_embeddings = text_embeddings.repeat_interleave(num_images_per_prompt, dim=0)
if clip_guidance_scale > 0:
if clip_prompt is not None:
@@ -217,6 +220,8 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
clip_text_input = text_input.input_ids.to(self.device)
text_embeddings_clip = self.clip_model.get_text_features(clip_text_input)
text_embeddings_clip = text_embeddings_clip / text_embeddings_clip.norm(p=2, dim=-1, keepdim=True)
# duplicate text embeddings clip for each generation per prompt
text_embeddings_clip = text_embeddings_clip.repeat_interleave(num_images_per_prompt, dim=0)
# here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
# of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
@@ -225,10 +230,10 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
# get unconditional embeddings for classifier free guidance
if do_classifier_free_guidance:
max_length = text_input.input_ids.shape[-1]
uncond_input = self.tokenizer(
[""] * batch_size, padding="max_length", max_length=max_length, return_tensors="pt"
)
uncond_input = self.tokenizer([""], padding="max_length", max_length=max_length, return_tensors="pt")
uncond_embeddings = self.text_encoder(uncond_input.input_ids.to(self.device))[0]
# duplicate unconditional embeddings for each generation per prompt
uncond_embeddings = uncond_embeddings.repeat_interleave(num_images_per_prompt, dim=0)
# For classifier free guidance, we need to do two forward passes.
# Here we concatenate the unconditional and text embeddings into a single batch
@@ -240,18 +245,20 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
# Unlike in other pipelines, latents need to be generated in the target device
# for 1-to-1 results reproducibility with the CompVis implementation.
# However this currently doesn't work in `mps`.
latents_device = "cpu" if self.device.type == "mps" else self.device
latents_shape = (batch_size, self.unet.in_channels, height // 8, width // 8)
latents_shape = (batch_size * num_images_per_prompt, self.unet.in_channels, height // 8, width // 8)
latents_dtype = text_embeddings.dtype
if latents is None:
latents = torch.randn(
latents_shape,
generator=generator,
device=latents_device,
)
if self.device.type == "mps":
# randn does not exist on mps
latents = torch.randn(latents_shape, generator=generator, device="cpu", dtype=latents_dtype).to(
self.device
)
else:
latents = torch.randn(latents_shape, generator=generator, device=self.device, dtype=latents_dtype)
else:
if latents.shape != latents_shape:
raise ValueError(f"Unexpected latents shape, got {latents.shape}, expected {latents_shape}")
latents = latents.to(self.device)
latents = latents.to(self.device)
# set timesteps
accepts_offset = "offset" in set(inspect.signature(self.scheduler.set_timesteps).parameters.keys())
@@ -261,17 +268,17 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
self.scheduler.set_timesteps(num_inference_steps, **extra_set_kwargs)
# if we use LMSDiscreteScheduler, let's make sure latents are multiplied by sigmas
if isinstance(self.scheduler, LMSDiscreteScheduler):
latents = latents * self.scheduler.sigmas[0]
# Some schedulers like PNDM have timesteps as arrays
# It's more optimized to move all timesteps to correct device beforehand
timesteps_tensor = self.scheduler.timesteps.to(self.device)
for i, t in enumerate(self.progress_bar(self.scheduler.timesteps)):
# scale the initial noise by the standard deviation required by the scheduler
latents = latents * self.scheduler.init_noise_sigma
for i, t in enumerate(self.progress_bar(timesteps_tensor)):
# expand the latents if we are doing classifier free guidance
latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents
if isinstance(self.scheduler, LMSDiscreteScheduler):
sigma = self.scheduler.sigmas[i]
# the model input needs to be scaled to match the continuous ODE formulation in K-LMS
latent_model_input = latent_model_input / ((sigma**2 + 1) ** 0.5)
latent_model_input = self.scheduler.scale_model_input(latent_model_input, t)
# predict the noise residual
noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=text_embeddings).sample
@@ -299,10 +306,7 @@ class CLIPGuidedStableDiffusion(DiffusionPipeline):
)
# compute the previous noisy sample x_t -> x_t-1
if isinstance(self.scheduler, LMSDiscreteScheduler):
latents = self.scheduler.step(noise_pred, i, latents).prev_sample
else:
latents = self.scheduler.step(noise_pred, t, latents).prev_sample
latents = self.scheduler.step(noise_pred, t, latents).prev_sample
# scale and decode the image latents with vae
latents = 1 / 0.18215 * latents