diff options
Diffstat (limited to 'pipelines/stable_diffusion')
-rw-r--r-- | pipelines/stable_diffusion/clip_guided_stable_diffusion.py | 457 |
1 files changed, 457 insertions, 0 deletions
diff --git a/pipelines/stable_diffusion/clip_guided_stable_diffusion.py b/pipelines/stable_diffusion/clip_guided_stable_diffusion.py new file mode 100644 index 0000000..306d9a9 --- /dev/null +++ b/pipelines/stable_diffusion/clip_guided_stable_diffusion.py | |||
@@ -0,0 +1,457 @@ | |||
1 | import inspect | ||
2 | import warnings | ||
3 | from typing import List, Optional, Union | ||
4 | |||
5 | import torch | ||
6 | from torch import nn | ||
7 | from torch.nn import functional as F | ||
8 | |||
9 | from diffusers.configuration_utils import FrozenDict | ||
10 | from diffusers import AutoencoderKL, DiffusionPipeline, DDIMScheduler, LMSDiscreteScheduler, PNDMScheduler, UNet2DConditionModel | ||
11 | from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion import StableDiffusionPipelineOutput | ||
12 | from diffusers.utils import logging | ||
13 | from torchvision import transforms | ||
14 | from transformers import CLIPFeatureExtractor, CLIPModel, CLIPTextModel, CLIPTokenizer | ||
15 | from schedulers.scheduling_euler_a import EulerAScheduler, CFGDenoiserForward | ||
16 | |||
17 | logger = logging.get_logger(__name__) # pylint: disable=invalid-name | ||
18 | |||
19 | |||
20 | class MakeCutouts(nn.Module): | ||
21 | def __init__(self, cut_size, cut_power=1.0): | ||
22 | super().__init__() | ||
23 | |||
24 | self.cut_size = cut_size | ||
25 | self.cut_power = cut_power | ||
26 | |||
27 | def forward(self, pixel_values, num_cutouts): | ||
28 | sideY, sideX = pixel_values.shape[2:4] | ||
29 | max_size = min(sideX, sideY) | ||
30 | min_size = min(sideX, sideY, self.cut_size) | ||
31 | cutouts = [] | ||
32 | for _ in range(num_cutouts): | ||
33 | size = int(torch.rand([]) ** self.cut_power * (max_size - min_size) + min_size) | ||
34 | offsetx = torch.randint(0, sideX - size + 1, ()) | ||
35 | offsety = torch.randint(0, sideY - size + 1, ()) | ||
36 | cutout = pixel_values[:, :, offsety: offsety + size, offsetx: offsetx + size] | ||
37 | cutouts.append(F.adaptive_avg_pool2d(cutout, self.cut_size)) | ||
38 | return torch.cat(cutouts) | ||
39 | |||
40 | |||
41 | def spherical_dist_loss(x, y): | ||
42 | x = F.normalize(x, dim=-1) | ||
43 | y = F.normalize(y, dim=-1) | ||
44 | return (x - y).norm(dim=-1).div(2).arcsin().pow(2).mul(2) | ||
45 | |||
46 | |||
47 | def set_requires_grad(model, value): | ||
48 | for param in model.parameters(): | ||
49 | param.requires_grad = value | ||
50 | |||
51 | |||
52 | class CLIPGuidedStableDiffusion(DiffusionPipeline): | ||
53 | """CLIP guided stable diffusion based on the amazing repo by @crowsonkb and @Jack000 | ||
54 | - https://github.com/Jack000/glid-3-xl | ||
55 | - https://github.dev/crowsonkb/k-diffusion | ||
56 | """ | ||
57 | |||
58 | def __init__( | ||
59 | self, | ||
60 | vae: AutoencoderKL, | ||
61 | text_encoder: CLIPTextModel, | ||
62 | clip_model: CLIPModel, | ||
63 | tokenizer: CLIPTokenizer, | ||
64 | unet: UNet2DConditionModel, | ||
65 | scheduler: Union[DDIMScheduler, PNDMScheduler, LMSDiscreteScheduler], | ||
66 | feature_extractor: CLIPFeatureExtractor, | ||
67 | **kwargs, | ||
68 | ): | ||
69 | super().__init__() | ||
70 | |||
71 | if hasattr(scheduler.config, "steps_offset") and scheduler.config.steps_offset != 1: | ||
72 | warnings.warn( | ||
73 | f"The configuration file of this scheduler: {scheduler} is outdated. `steps_offset`" | ||
74 | f" should be set to 1 instead of {scheduler.config.steps_offset}. Please make sure " | ||
75 | "to update the config accordingly as leaving `steps_offset` might led to incorrect results" | ||
76 | " in future versions. If you have downloaded this checkpoint from the Hugging Face Hub," | ||
77 | " it would be very nice if you could open a Pull request for the `scheduler/scheduler_config.json`" | ||
78 | " file", | ||
79 | DeprecationWarning, | ||
80 | ) | ||
81 | new_config = dict(scheduler.config) | ||
82 | new_config["steps_offset"] = 1 | ||
83 | scheduler._internal_dict = FrozenDict(new_config) | ||
84 | |||
85 | self.register_modules( | ||
86 | vae=vae, | ||
87 | text_encoder=text_encoder, | ||
88 | clip_model=clip_model, | ||
89 | tokenizer=tokenizer, | ||
90 | unet=unet, | ||
91 | scheduler=scheduler, | ||
92 | feature_extractor=feature_extractor, | ||
93 | ) | ||
94 | |||
95 | self.normalize = transforms.Normalize(mean=feature_extractor.image_mean, std=feature_extractor.image_std) | ||
96 | self.make_cutouts = MakeCutouts(feature_extractor.size) | ||
97 | |||
98 | set_requires_grad(self.text_encoder, False) | ||
99 | set_requires_grad(self.clip_model, False) | ||
100 | |||
101 | def enable_attention_slicing(self, slice_size: Optional[Union[str, int]] = "auto"): | ||
102 | r""" | ||
103 | Enable sliced attention computation. | ||
104 | |||
105 | When this option is enabled, the attention module will split the input tensor in slices, to compute attention | ||
106 | in several steps. This is useful to save some memory in exchange for a small speed decrease. | ||
107 | |||
108 | Args: | ||
109 | slice_size (`str` or `int`, *optional*, defaults to `"auto"`): | ||
110 | When `"auto"`, halves the input to the attention heads, so attention will be computed in two steps. If | ||
111 | a number is provided, uses as many slices as `attention_head_dim // slice_size`. In this case, | ||
112 | `attention_head_dim` must be a multiple of `slice_size`. | ||
113 | """ | ||
114 | if slice_size == "auto": | ||
115 | # half the attention head size is usually a good trade-off between | ||
116 | # speed and memory | ||
117 | slice_size = self.unet.config.attention_head_dim // 2 | ||
118 | self.unet.set_attention_slice(slice_size) | ||
119 | |||
120 | def disable_attention_slicing(self): | ||
121 | r""" | ||
122 | Disable sliced attention computation. If `enable_attention_slicing` was previously invoked, this method will go | ||
123 | back to computing attention in one step. | ||
124 | """ | ||
125 | # set slice_size = `None` to disable `attention slicing` | ||
126 | self.enable_attention_slicing(None) | ||
127 | |||
128 | def freeze_vae(self): | ||
129 | set_requires_grad(self.vae, False) | ||
130 | |||
131 | def unfreeze_vae(self): | ||
132 | set_requires_grad(self.vae, True) | ||
133 | |||
134 | def freeze_unet(self): | ||
135 | set_requires_grad(self.unet, False) | ||
136 | |||
137 | def unfreeze_unet(self): | ||
138 | set_requires_grad(self.unet, True) | ||
139 | |||
140 | @torch.enable_grad() | ||
141 | def cond_fn( | ||
142 | self, | ||
143 | latents, | ||
144 | timestep, | ||
145 | index, | ||
146 | text_embeddings, | ||
147 | noise_pred_original, | ||
148 | text_embeddings_clip, | ||
149 | clip_guidance_scale, | ||
150 | num_cutouts, | ||
151 | use_cutouts=True, | ||
152 | ): | ||
153 | latents = latents.detach().requires_grad_() | ||
154 | |||
155 | if isinstance(self.scheduler, LMSDiscreteScheduler): | ||
156 | sigma = self.scheduler.sigmas[index] | ||
157 | # the model input needs to be scaled to match the continuous ODE formulation in K-LMS | ||
158 | latent_model_input = latents / ((sigma**2 + 1) ** 0.5) | ||
159 | else: | ||
160 | latent_model_input = latents | ||
161 | |||
162 | # predict the noise residual | ||
163 | noise_pred = self.unet(latent_model_input, timestep, encoder_hidden_states=text_embeddings).sample | ||
164 | |||
165 | if isinstance(self.scheduler, PNDMScheduler): | ||
166 | alpha_prod_t = self.scheduler.alphas_cumprod[timestep] | ||
167 | beta_prod_t = 1 - alpha_prod_t | ||
168 | # compute predicted original sample from predicted noise also called | ||
169 | # "predicted x_0" of formula (12) from https://arxiv.org/pdf/2010.02502.pdf | ||
170 | pred_original_sample = (latents - beta_prod_t ** (0.5) * noise_pred) / alpha_prod_t ** (0.5) | ||
171 | |||
172 | fac = torch.sqrt(beta_prod_t) | ||
173 | sample = pred_original_sample * (fac) + latents * (1 - fac) | ||
174 | elif isinstance(self.scheduler, LMSDiscreteScheduler): | ||
175 | sigma = self.scheduler.sigmas[index] | ||
176 | sample = latents - sigma * noise_pred | ||
177 | else: | ||
178 | raise ValueError(f"scheduler type {type(self.scheduler)} not supported") | ||
179 | |||
180 | sample = 1 / 0.18215 * sample | ||
181 | image = self.vae.decode(sample).sample | ||
182 | image = (image / 2 + 0.5).clamp(0, 1) | ||
183 | |||
184 | if use_cutouts: | ||
185 | image = self.make_cutouts(image, num_cutouts) | ||
186 | else: | ||
187 | image = transforms.Resize(self.feature_extractor.size)(image) | ||
188 | image = self.normalize(image) | ||
189 | |||
190 | image_embeddings_clip = self.clip_model.get_image_features(image).float() | ||
191 | image_embeddings_clip = image_embeddings_clip / image_embeddings_clip.norm(p=2, dim=-1, keepdim=True) | ||
192 | |||
193 | if use_cutouts: | ||
194 | dists = spherical_dist_loss(image_embeddings_clip, text_embeddings_clip) | ||
195 | dists = dists.view([num_cutouts, sample.shape[0], -1]) | ||
196 | loss = dists.sum(2).mean(0).sum() * clip_guidance_scale | ||
197 | else: | ||
198 | loss = spherical_dist_loss(image_embeddings_clip, text_embeddings_clip).mean() * clip_guidance_scale | ||
199 | |||
200 | grads = -torch.autograd.grad(loss, latents)[0] | ||
201 | |||
202 | if isinstance(self.scheduler, LMSDiscreteScheduler): | ||
203 | latents = latents.detach() + grads * (sigma**2) | ||
204 | noise_pred = noise_pred_original | ||
205 | else: | ||
206 | noise_pred = noise_pred_original - torch.sqrt(beta_prod_t) * grads | ||
207 | return noise_pred, latents | ||
208 | |||
209 | @torch.no_grad() | ||
210 | def __call__( | ||
211 | self, | ||
212 | prompt: Union[str, List[str]], | ||
213 | negative_prompt: Optional[Union[str, List[str]]] = None, | ||
214 | height: Optional[int] = 512, | ||
215 | width: Optional[int] = 512, | ||
216 | num_inference_steps: Optional[int] = 50, | ||
217 | guidance_scale: Optional[float] = 7.5, | ||
218 | eta: Optional[float] = 0.0, | ||
219 | clip_guidance_scale: Optional[float] = 100, | ||
220 | clip_prompt: Optional[Union[str, List[str]]] = None, | ||
221 | num_cutouts: Optional[int] = 4, | ||
222 | use_cutouts: Optional[bool] = True, | ||
223 | generator: Optional[torch.Generator] = None, | ||
224 | latents: Optional[torch.FloatTensor] = None, | ||
225 | output_type: Optional[str] = "pil", | ||
226 | return_dict: bool = True, | ||
227 | ): | ||
228 | r""" | ||
229 | Function invoked when calling the pipeline for generation. | ||
230 | |||
231 | Args: | ||
232 | prompt (`str` or `List[str]`): | ||
233 | The prompt or prompts to guide the image generation. | ||
234 | height (`int`, *optional*, defaults to 512): | ||
235 | The height in pixels of the generated image. | ||
236 | width (`int`, *optional*, defaults to 512): | ||
237 | The width in pixels of the generated image. | ||
238 | num_inference_steps (`int`, *optional*, defaults to 50): | ||
239 | The number of denoising steps. More denoising steps usually lead to a higher quality image at the | ||
240 | expense of slower inference. | ||
241 | guidance_scale (`float`, *optional*, defaults to 7.5): | ||
242 | Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://arxiv.org/abs/2207.12598). | ||
243 | `guidance_scale` is defined as `w` of equation 2. of [Imagen | ||
244 | Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale > | ||
245 | 1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`, | ||
246 | usually at the expense of lower image quality. | ||
247 | eta (`float`, *optional*, defaults to 0.0): | ||
248 | Corresponds to parameter eta (η) in the DDIM paper: https://arxiv.org/abs/2010.02502. Only applies to | ||
249 | [`schedulers.DDIMScheduler`], will be ignored for others. | ||
250 | generator (`torch.Generator`, *optional*): | ||
251 | A [torch generator](https://pytorch.org/docs/stable/generated/torch.Generator.html) to make generation | ||
252 | deterministic. | ||
253 | latents (`torch.FloatTensor`, *optional*): | ||
254 | Pre-generated noisy latents, sampled from a Gaussian distribution, to be used as inputs for image | ||
255 | generation. Can be used to tweak the same generation with different prompts. If not provided, a latents | ||
256 | tensor will ge generated by sampling using the supplied random `generator`. | ||
257 | output_type (`str`, *optional*, defaults to `"pil"`): | ||
258 | The output format of the generate image. Choose between | ||
259 | [PIL](https://pillow.readthedocs.io/en/stable/): `PIL.Image.Image` or `np.array`. | ||
260 | return_dict (`bool`, *optional*, defaults to `True`): | ||
261 | Whether or not to return a [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] instead of a | ||
262 | plain tuple. | ||
263 | |||
264 | Returns: | ||
265 | [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] or `tuple`: | ||
266 | [`~pipelines.stable_diffusion.StableDiffusionPipelineOutput`] if `return_dict` is True, otherwise a `tuple. | ||
267 | When returning a tuple, the first element is a list with the generated images, and the second element is a | ||
268 | list of `bool`s denoting whether the corresponding generated image likely represents "not-safe-for-work" | ||
269 | (nsfw) content, according to the `safety_checker`. | ||
270 | """ | ||
271 | |||
272 | if isinstance(prompt, str): | ||
273 | batch_size = 1 | ||
274 | elif isinstance(prompt, list): | ||
275 | batch_size = len(prompt) | ||
276 | else: | ||
277 | raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}") | ||
278 | |||
279 | if negative_prompt is None: | ||
280 | negative_prompt = [""] * batch_size | ||
281 | elif isinstance(negative_prompt, str): | ||
282 | negative_prompt = [negative_prompt] * batch_size | ||
283 | elif isinstance(negative_prompt, list): | ||
284 | if len(negative_prompt) != batch_size: | ||
285 | raise ValueError( | ||
286 | f"`prompt` and `negative_prompt` have to be the same length, but are {len(prompt)} and {len(negative_prompt)}") | ||
287 | else: | ||
288 | raise ValueError(f"`negative_prompt` has to be of type `str` or `list` but is {type(negative_prompt)}") | ||
289 | |||
290 | if height % 8 != 0 or width % 8 != 0: | ||
291 | raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.") | ||
292 | |||
293 | # get prompt text embeddings | ||
294 | text_inputs = self.tokenizer( | ||
295 | prompt, | ||
296 | padding="max_length", | ||
297 | max_length=self.tokenizer.model_max_length, | ||
298 | return_tensors="pt", | ||
299 | ) | ||
300 | text_input_ids = text_inputs.input_ids | ||
301 | |||
302 | if text_input_ids.shape[-1] > self.tokenizer.model_max_length: | ||
303 | removed_text = self.tokenizer.batch_decode(text_input_ids[:, self.tokenizer.model_max_length:]) | ||
304 | logger.warning( | ||
305 | "The following part of your input was truncated because CLIP can only handle sequences up to" | ||
306 | f" {self.tokenizer.model_max_length} tokens: {removed_text}" | ||
307 | ) | ||
308 | text_input_ids = text_input_ids[:, : self.tokenizer.model_max_length] | ||
309 | text_embeddings = self.text_encoder(text_input_ids.to(self.device))[0] | ||
310 | |||
311 | if clip_guidance_scale > 0: | ||
312 | if clip_prompt is not None: | ||
313 | clip_text_inputs = self.tokenizer( | ||
314 | clip_prompt, | ||
315 | padding="max_length", | ||
316 | max_length=self.tokenizer.model_max_length, | ||
317 | truncation=True, | ||
318 | return_tensors="pt", | ||
319 | ) | ||
320 | clip_text_input_ids = clip_text_inputs.input_ids | ||
321 | else: | ||
322 | clip_text_input_ids = text_input_ids | ||
323 | text_embeddings_clip = self.clip_model.get_text_features(clip_text_input_ids.to(self.device)) | ||
324 | text_embeddings_clip = text_embeddings_clip / text_embeddings_clip.norm(p=2, dim=-1, keepdim=True) | ||
325 | |||
326 | # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2) | ||
327 | # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1` | ||
328 | # corresponds to doing no classifier free guidance. | ||
329 | do_classifier_free_guidance = guidance_scale > 1.0 | ||
330 | # get unconditional embeddings for classifier free guidance | ||
331 | if do_classifier_free_guidance: | ||
332 | max_length = text_input_ids.shape[-1] | ||
333 | uncond_input = self.tokenizer( | ||
334 | negative_prompt, padding="max_length", max_length=max_length, return_tensors="pt" | ||
335 | ) | ||
336 | uncond_embeddings = self.text_encoder(uncond_input.input_ids.to(self.device))[0] | ||
337 | |||
338 | # For classifier free guidance, we need to do two forward passes. | ||
339 | # Here we concatenate the unconditional and text embeddings into a single batch | ||
340 | # to avoid doing two forward passes | ||
341 | text_embeddings = torch.cat([uncond_embeddings, text_embeddings]) | ||
342 | |||
343 | # get the initial random noise unless the user supplied it | ||
344 | |||
345 | # Unlike in other pipelines, latents need to be generated in the target device | ||
346 | # for 1-to-1 results reproducibility with the CompVis implementation. | ||
347 | # However this currently doesn't work in `mps`. | ||
348 | latents_device = "cpu" if self.device.type == "mps" else self.device | ||
349 | latents_shape = (batch_size, self.unet.in_channels, height // 8, width // 8) | ||
350 | if latents is None: | ||
351 | latents = torch.randn( | ||
352 | latents_shape, | ||
353 | generator=generator, | ||
354 | device=latents_device, | ||
355 | dtype=text_embeddings.dtype, | ||
356 | ) | ||
357 | else: | ||
358 | if latents.shape != latents_shape: | ||
359 | raise ValueError(f"Unexpected latents shape, got {latents.shape}, expected {latents_shape}") | ||
360 | latents = latents.to(self.device) | ||
361 | |||
362 | # set timesteps | ||
363 | self.scheduler.set_timesteps(num_inference_steps) | ||
364 | |||
365 | # Some schedulers like PNDM have timesteps as arrays | ||
366 | # It's more optimzed to move all timesteps to correct device beforehand | ||
367 | if torch.is_tensor(self.scheduler.timesteps): | ||
368 | timesteps_tensor = self.scheduler.timesteps.to(self.device) | ||
369 | else: | ||
370 | timesteps_tensor = torch.tensor(self.scheduler.timesteps.copy(), device=self.device) | ||
371 | |||
372 | # if we use LMSDiscreteScheduler, let's make sure latents are multiplied by sigmas | ||
373 | if isinstance(self.scheduler, LMSDiscreteScheduler): | ||
374 | latents = latents * self.scheduler.sigmas[0] | ||
375 | elif isinstance(self.scheduler, EulerAScheduler): | ||
376 | sigma = self.scheduler.timesteps[0] | ||
377 | latents = latents * sigma | ||
378 | |||
379 | # prepare extra kwargs for the scheduler step, since not all schedulers have the same signature | ||
380 | # eta (η) is only used with the DDIMScheduler, it will be ignored for other schedulers. | ||
381 | # eta corresponds to η in DDIM paper: https://arxiv.org/abs/2010.02502 | ||
382 | # and should be between [0, 1] | ||
383 | scheduler_step_args = set(inspect.signature(self.scheduler.step).parameters.keys()) | ||
384 | accepts_eta = "eta" in scheduler_step_args | ||
385 | extra_step_kwargs = {} | ||
386 | if accepts_eta: | ||
387 | extra_step_kwargs["eta"] = eta | ||
388 | accepts_generator = "generator" in scheduler_step_args | ||
389 | if generator is not None and accepts_generator: | ||
390 | extra_step_kwargs["generator"] = generator | ||
391 | |||
392 | for i, t in enumerate(self.progress_bar(timesteps_tensor)): | ||
393 | # expand the latents if we are doing classifier free guidance | ||
394 | latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents | ||
395 | if isinstance(self.scheduler, LMSDiscreteScheduler): | ||
396 | sigma = self.scheduler.sigmas[i] | ||
397 | # the model input needs to be scaled to match the continuous ODE formulation in K-LMS | ||
398 | latent_model_input = latent_model_input / ((sigma**2 + 1) ** 0.5) | ||
399 | |||
400 | noise_pred = None | ||
401 | if isinstance(self.scheduler, EulerAScheduler): | ||
402 | sigma = t.reshape(1) | ||
403 | sigma_in = torch.cat([sigma] * 2) | ||
404 | # noise_pred = model(latent_model_input,sigma_in,uncond_embeddings, text_embeddings,guidance_scale) | ||
405 | noise_pred = CFGDenoiserForward(self.unet, latent_model_input, sigma_in, | ||
406 | text_embeddings, guidance_scale, DSsigmas=self.scheduler.DSsigmas) | ||
407 | # noise_pred = self.unet(latent_model_input, sigma_in, encoder_hidden_states=text_embeddings).sample | ||
408 | else: | ||
409 | # predict the noise residual | ||
410 | noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=text_embeddings).sample | ||
411 | |||
412 | # perform guidance | ||
413 | if do_classifier_free_guidance: | ||
414 | noise_pred_uncond, noise_pred_text = noise_pred.chunk(2) | ||
415 | noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond) | ||
416 | |||
417 | # perform clip guidance | ||
418 | if clip_guidance_scale > 0: | ||
419 | text_embeddings_for_guidance = ( | ||
420 | text_embeddings.chunk(2)[1] if do_classifier_free_guidance else text_embeddings | ||
421 | ) | ||
422 | noise_pred, latents = self.cond_fn( | ||
423 | latents, | ||
424 | t, | ||
425 | i, | ||
426 | text_embeddings_for_guidance, | ||
427 | noise_pred, | ||
428 | text_embeddings_clip, | ||
429 | clip_guidance_scale, | ||
430 | num_cutouts, | ||
431 | use_cutouts, | ||
432 | ) | ||
433 | |||
434 | # compute the previous noisy sample x_t -> x_t-1 | ||
435 | if isinstance(self.scheduler, LMSDiscreteScheduler): | ||
436 | latents = self.scheduler.step(noise_pred, i, latents, **extra_step_kwargs).prev_sample | ||
437 | elif isinstance(self.scheduler, EulerAScheduler): | ||
438 | if i < self.scheduler.timesteps.shape[0] - 1: # avoid out of bound error | ||
439 | t_prev = self.scheduler.timesteps[i+1] | ||
440 | latents = self.scheduler.step(noise_pred, t, t_prev, latents, **extra_step_kwargs).prev_sample | ||
441 | else: | ||
442 | latents = self.scheduler.step(noise_pred, t, latents, **extra_step_kwargs).prev_sample | ||
443 | |||
444 | # scale and decode the image latents with vae | ||
445 | latents = 1 / 0.18215 * latents | ||
446 | image = self.vae.decode(latents).sample | ||
447 | |||
448 | image = (image / 2 + 0.5).clamp(0, 1) | ||
449 | image = image.cpu().permute(0, 2, 3, 1).numpy() | ||
450 | |||
451 | if output_type == "pil": | ||
452 | image = self.numpy_to_pil(image) | ||
453 | |||
454 | if not return_dict: | ||
455 | return (image, None) | ||
456 | |||
457 | return StableDiffusionPipelineOutput(images=image, nsfw_content_detected=None) | ||