File size: 9,478 Bytes
0b1273f |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 |
from typing import Optional
import torch
from PIL import Image
from tqdm.auto import tqdm
from transformers import CLIPTextModel, CLIPTokenizer
from diffusers import AutoencoderKL, DDIMScheduler, DiffusionPipeline, UNet2DConditionModel
from diffusers.image_processor import VaeImageProcessor
from diffusers.utils import (
deprecate,
)
class EDICTPipeline(DiffusionPipeline):
def __init__(
self,
vae: AutoencoderKL,
text_encoder: CLIPTextModel,
tokenizer: CLIPTokenizer,
unet: UNet2DConditionModel,
scheduler: DDIMScheduler,
mixing_coeff: float = 0.93,
leapfrog_steps: bool = True,
):
self.mixing_coeff = mixing_coeff
self.leapfrog_steps = leapfrog_steps
super().__init__()
self.register_modules(
vae=vae,
text_encoder=text_encoder,
tokenizer=tokenizer,
unet=unet,
scheduler=scheduler,
)
self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor)
def _encode_prompt(
self, prompt: str, negative_prompt: Optional[str] = None, do_classifier_free_guidance: bool = False
):
text_inputs = self.tokenizer(
prompt,
padding="max_length",
max_length=self.tokenizer.model_max_length,
truncation=True,
return_tensors="pt",
)
prompt_embeds = self.text_encoder(text_inputs.input_ids.to(self.device)).last_hidden_state
prompt_embeds = prompt_embeds.to(dtype=self.text_encoder.dtype, device=self.device)
if do_classifier_free_guidance:
uncond_tokens = "" if negative_prompt is None else negative_prompt
uncond_input = self.tokenizer(
uncond_tokens,
padding="max_length",
max_length=self.tokenizer.model_max_length,
truncation=True,
return_tensors="pt",
)
negative_prompt_embeds = self.text_encoder(uncond_input.input_ids.to(self.device)).last_hidden_state
prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds])
return prompt_embeds
def denoise_mixing_layer(self, x: torch.Tensor, y: torch.Tensor):
x = self.mixing_coeff * x + (1 - self.mixing_coeff) * y
y = self.mixing_coeff * y + (1 - self.mixing_coeff) * x
return [x, y]
def noise_mixing_layer(self, x: torch.Tensor, y: torch.Tensor):
y = (y - (1 - self.mixing_coeff) * x) / self.mixing_coeff
x = (x - (1 - self.mixing_coeff) * y) / self.mixing_coeff
return [x, y]
def _get_alpha_and_beta(self, t: torch.Tensor):
# as self.alphas_cumprod is always in cpu
t = int(t)
alpha_prod = self.scheduler.alphas_cumprod[t] if t >= 0 else self.scheduler.final_alpha_cumprod
return alpha_prod, 1 - alpha_prod
def noise_step(
self,
base: torch.Tensor,
model_input: torch.Tensor,
model_output: torch.Tensor,
timestep: torch.Tensor,
):
prev_timestep = timestep - self.scheduler.config.num_train_timesteps / self.scheduler.num_inference_steps
alpha_prod_t, beta_prod_t = self._get_alpha_and_beta(timestep)
alpha_prod_t_prev, beta_prod_t_prev = self._get_alpha_and_beta(prev_timestep)
a_t = (alpha_prod_t_prev / alpha_prod_t) ** 0.5
b_t = -a_t * (beta_prod_t**0.5) + beta_prod_t_prev**0.5
next_model_input = (base - b_t * model_output) / a_t
return model_input, next_model_input.to(base.dtype)
def denoise_step(
self,
base: torch.Tensor,
model_input: torch.Tensor,
model_output: torch.Tensor,
timestep: torch.Tensor,
):
prev_timestep = timestep - self.scheduler.config.num_train_timesteps / self.scheduler.num_inference_steps
alpha_prod_t, beta_prod_t = self._get_alpha_and_beta(timestep)
alpha_prod_t_prev, beta_prod_t_prev = self._get_alpha_and_beta(prev_timestep)
a_t = (alpha_prod_t_prev / alpha_prod_t) ** 0.5
b_t = -a_t * (beta_prod_t**0.5) + beta_prod_t_prev**0.5
next_model_input = a_t * base + b_t * model_output
return model_input, next_model_input.to(base.dtype)
@torch.no_grad()
def decode_latents(self, latents: torch.Tensor):
latents = 1 / self.vae.config.scaling_factor * latents
image = self.vae.decode(latents).sample
image = (image / 2 + 0.5).clamp(0, 1)
return image
@torch.no_grad()
def prepare_latents(
self,
image: Image.Image,
text_embeds: torch.Tensor,
timesteps: torch.Tensor,
guidance_scale: float,
generator: Optional[torch.Generator] = None,
):
do_classifier_free_guidance = guidance_scale > 1.0
image = image.to(device=self.device, dtype=text_embeds.dtype)
latent = self.vae.encode(image).latent_dist.sample(generator)
latent = self.vae.config.scaling_factor * latent
coupled_latents = [latent.clone(), latent.clone()]
for i, t in tqdm(enumerate(timesteps), total=len(timesteps)):
coupled_latents = self.noise_mixing_layer(x=coupled_latents[0], y=coupled_latents[1])
# j - model_input index, k - base index
for j in range(2):
k = j ^ 1
if self.leapfrog_steps:
if i % 2 == 0:
k, j = j, k
model_input = coupled_latents[j]
base = coupled_latents[k]
latent_model_input = torch.cat([model_input] * 2) if do_classifier_free_guidance else model_input
noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=text_embeds).sample
if do_classifier_free_guidance:
noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
base, model_input = self.noise_step(
base=base,
model_input=model_input,
model_output=noise_pred,
timestep=t,
)
coupled_latents[k] = model_input
return coupled_latents
@torch.no_grad()
def __call__(
self,
base_prompt: str,
target_prompt: str,
image: Image.Image,
guidance_scale: float = 3.0,
num_inference_steps: int = 50,
strength: float = 0.8,
negative_prompt: Optional[str] = None,
generator: Optional[torch.Generator] = None,
output_type: Optional[str] = "pil",
):
do_classifier_free_guidance = guidance_scale > 1.0
image = self.image_processor.preprocess(image)
base_embeds = self._encode_prompt(base_prompt, negative_prompt, do_classifier_free_guidance)
target_embeds = self._encode_prompt(target_prompt, negative_prompt, do_classifier_free_guidance)
self.scheduler.set_timesteps(num_inference_steps, self.device)
t_limit = num_inference_steps - int(num_inference_steps * strength)
fwd_timesteps = self.scheduler.timesteps[t_limit:]
bwd_timesteps = fwd_timesteps.flip(0)
coupled_latents = self.prepare_latents(image, base_embeds, bwd_timesteps, guidance_scale, generator)
for i, t in tqdm(enumerate(fwd_timesteps), total=len(fwd_timesteps)):
# j - model_input index, k - base index
for k in range(2):
j = k ^ 1
if self.leapfrog_steps:
if i % 2 == 1:
k, j = j, k
model_input = coupled_latents[j]
base = coupled_latents[k]
latent_model_input = torch.cat([model_input] * 2) if do_classifier_free_guidance else model_input
noise_pred = self.unet(latent_model_input, t, encoder_hidden_states=target_embeds).sample
if do_classifier_free_guidance:
noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
noise_pred = noise_pred_uncond + guidance_scale * (noise_pred_text - noise_pred_uncond)
base, model_input = self.denoise_step(
base=base,
model_input=model_input,
model_output=noise_pred,
timestep=t,
)
coupled_latents[k] = model_input
coupled_latents = self.denoise_mixing_layer(x=coupled_latents[0], y=coupled_latents[1])
# either one is fine
final_latent = coupled_latents[0]
if output_type not in ["latent", "pt", "np", "pil"]:
deprecation_message = (
f"the output_type {output_type} is outdated. Please make sure to set it to one of these instead: "
"`pil`, `np`, `pt`, `latent`"
)
deprecate("Unsupported output_type", "1.0.0", deprecation_message, standard_warn=False)
output_type = "np"
if output_type == "latent":
image = final_latent
else:
image = self.decode_latents(final_latent)
image = self.image_processor.postprocess(image, output_type=output_type)
return image
|