DRAFT: Cross-Attention Control

Signed-off-by: Ben Alkov <ben.alkov@gmail.com>
This commit is contained in:
Ben Alkov 2022-10-15 17:09:47 -04:00 committed by Damian at mba
parent 92d4dfaabf
commit 07a3df6001
2 changed files with 362 additions and 0 deletions

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# Functions supporting Cross-Attention Control
# Copied from https://github.com/bloc97/CrossAttentionControl
from difflib import SequenceMatcher
import torch
def prompt_token(prompt, index, clip_tokenizer):
tokens = clip_tokenizer(prompt,
padding='max_length',
max_length=clip_tokenizer.model_max_length,
truncation=True,
return_tensors='pt',
return_overflowing_tokens=True
).input_ids[0]
return clip_tokenizer.decode(tokens[index:index+1])
def init_attention_weights(weight_tuples, clip_tokenizer, unet, device):
tokens_length = clip_tokenizer.model_max_length
weights = torch.ones(tokens_length)
for i, w in weight_tuples:
if i < tokens_length and i >= 0:
weights[i] = w
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn2' in name:
module.last_attn_slice_weights = weights.to(device)
if module_name == 'CrossAttention' and 'attn1' in name:
module.last_attn_slice_weights = None
def init_attention_edit(tokens, tokens_edit, clip_tokenizer, unet, device):
tokens_length = clip_tokenizer.model_max_length
mask = torch.zeros(tokens_length)
indices_target = torch.arange(tokens_length, dtype=torch.long)
indices = torch.zeros(tokens_length, dtype=torch.long)
tokens = tokens.input_ids.numpy()[0]
tokens_edit = tokens_edit.input_ids.numpy()[0]
for name, a0, a1, b0, b1 in SequenceMatcher(None, tokens, tokens_edit).get_opcodes():
if b0 < tokens_length:
if name == 'equal' or (name == 'replace' and a1-a0 == b1-b0):
mask[b0:b1] = 1
indices[b0:b1] = indices_target[a0:a1]
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn2' in name:
module.last_attn_slice_mask = mask.to(device)
module.last_attn_slice_indices = indices.to(device)
if module_name == 'CrossAttention' and 'attn1' in name:
module.last_attn_slice_mask = None
module.last_attn_slice_indices = None
def init_attention_func(unet):
# ORIGINAL SOURCE CODE: https://github.com/huggingface/diffusers/blob/91ddd2a25b848df0fa1262d4f1cd98c7ccb87750/src/diffusers/models/attention.py#L276
def new_attention(self, query, key, value):
# TODO: use baddbmm for better performance
attention_scores = torch.matmul(query, key.transpose(-1, -2)) * self.scale
attn_slice = attention_scores.softmax(dim=-1)
# compute attention output
if self.use_last_attn_slice:
if self.last_attn_slice_mask is not None:
new_attn_slice = (torch.index_select(self.last_attn_slice, -1,
self.last_attn_slice_indices))
attn_slice = (attn_slice * (1 - self.last_attn_slice_mask)
+ new_attn_slice * self.last_attn_slice_mask)
else:
attn_slice = self.last_attn_slice
self.use_last_attn_slice = False
if self.save_last_attn_slice:
self.last_attn_slice = attn_slice
self.save_last_attn_slice = False
if self.use_last_attn_weights and self.last_attn_slice_weights is not None:
attn_slice = attn_slice * self.last_attn_slice_weights
self.use_last_attn_weights = False
hidden_states = torch.matmul(attn_slice, value)
# reshape hidden_states
return self.reshape_batch_dim_to_heads(hidden_states)
def new_sliced_attention(self, query, key, value, sequence_length, dim):
batch_size_attention = query.shape[0]
hidden_states = torch.zeros(
(batch_size_attention, sequence_length, dim // self.heads),
device=query.device, dtype=query.dtype
)
slice_size = self._slice_size if self._slice_size is not None else hidden_states.shape[0]
for i in range(hidden_states.shape[0] // slice_size):
start_idx = i * slice_size
end_idx = (i + 1) * slice_size
attn_slice = (
torch.matmul(query[start_idx:end_idx],
key[start_idx:end_idx].transpose(1, 2)) * self.scale
) # TODO: use baddbmm for better performance
attn_slice = attn_slice.softmax(dim=-1)
if self.use_last_attn_slice:
if self.last_attn_slice_mask is not None:
new_attn_slice = (torch.index_select(self.last_attn_slice,
-1, self.last_attn_slice_indices))
attn_slice = (attn_slice * (1 - self.last_attn_slice_mask)
+ new_attn_slice * self.last_attn_slice_mask)
else:
attn_slice = self.last_attn_slice
self.use_last_attn_slice = False
if self.save_last_attn_slice:
self.last_attn_slice = attn_slice
self.save_last_attn_slice = False
if self.use_last_attn_weights and self.last_attn_slice_weights is not None:
attn_slice = attn_slice * self.last_attn_slice_weights
self.use_last_attn_weights = False
attn_slice = torch.matmul(attn_slice, value[start_idx:end_idx])
hidden_states[start_idx:end_idx] = attn_slice
return self.reshape_batch_dim_to_heads(hidden_states) # reshape hidden_states
for _, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention':
module.last_attn_slice = None
module.use_last_attn_slice = False
module.use_last_attn_weights = False
module.save_last_attn_slice = False
module._sliced_attention = new_sliced_attention.__get__(module, type(module))
module._attention = new_attention.__get__(module, type(module))
def use_last_tokens_attention(unet, use=True):
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn2' in name:
module.use_last_attn_slice = use
def use_last_tokens_attention_weights(unet, use=True):
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn2' in name:
module.use_last_attn_weights = use
def use_last_self_attention(unet, use=True):
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn1' in name:
module.use_last_attn_slice = use
def save_last_tokens_attention(unet, save=True):
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn2' in name:
module.save_last_attn_slice = save
def save_last_self_attention(unet, save=True):
for name, module in unet.named_modules():
module_name = type(module).__name__
if module_name == 'CrossAttention' and 'attn1' in name:
module.save_last_attn_slice = save

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import random
import numpy as np
import torch
from diffusers import (LMSDiscreteScheduler)
from PIL import Image
from torch import autocast
from tqdm.auto import tqdm
import c_a_c
@torch.no_grad()
def stablediffusion(
clip,
clip_tokenizer,
device,
vae,
unet,
prompt='',
prompt_edit=None,
prompt_edit_token_weights=None,
prompt_edit_tokens_start=0.0,
prompt_edit_tokens_end=1.0,
prompt_edit_spatial_start=0.0,
prompt_edit_spatial_end=1.0,
guidance_scale=7.5,
steps=50,
seed=None,
width=512,
height=512,
init_image=None,
init_image_strength=0.5,
):
if prompt_edit_token_weights is None:
prompt_edit_token_weights = []
# Change size to multiple of 64 to prevent size mismatches inside model
width = width - width % 64
height = height - height % 64
# If seed is None, randomly select seed from 0 to 2^32-1
if seed is None: seed = random.randrange(2**32 - 1)
generator = torch.cuda.manual_seed(seed)
# Set inference timesteps to scheduler
scheduler = LMSDiscreteScheduler(beta_start=0.00085,
beta_end=0.012,
beta_schedule='scaled_linear',
num_train_timesteps=1000,
)
scheduler.set_timesteps(steps)
# Preprocess image if it exists (img2img)
if init_image is not None:
# Resize and transpose for numpy b h w c -> torch b c h w
init_image = init_image.resize((width, height), resample=Image.Resampling.LANCZOS)
init_image = np.array(init_image).astype(np.float32) / 255.0 * 2.0 - 1.0
init_image = torch.from_numpy(init_image[np.newaxis, ...].transpose(0, 3, 1, 2))
# If there is alpha channel, composite alpha for white, as the diffusion
# model does not support alpha channel
if init_image.shape[1] > 3:
init_image = init_image[:, :3] * init_image[:, 3:] + (1 - init_image[:, 3:])
# Move image to GPU
init_image = init_image.to(device)
# Encode image
with autocast(device):
init_latent = (vae.encode(init_image)
.latent_dist
.sample(generator=generator)
* 0.18215)
t_start = steps - int(steps * init_image_strength)
else:
init_latent = torch.zeros((1, unet.in_channels, height // 8, width // 8),
device=device)
t_start = 0
# Generate random normal noise
noise = torch.randn(init_latent.shape, generator=generator, device=device)
latent = scheduler.add_noise(init_latent,
noise,
torch.tensor([scheduler.timesteps[t_start]], device=device)
).to(device)
# Process clip
with autocast(device):
tokens_uncond = clip_tokenizer('', padding='max_length',
max_length=clip_tokenizer.model_max_length,
truncation=True, return_tensors='pt',
return_overflowing_tokens=True
)
embedding_uncond = clip(tokens_uncond.input_ids.to(device)).last_hidden_state
tokens_cond = clip_tokenizer(prompt, padding='max_length',
max_length=clip_tokenizer.model_max_length,
truncation=True, return_tensors='pt',
return_overflowing_tokens=True
)
embedding_cond = clip(tokens_cond.input_ids.to(device)).last_hidden_state
# Process prompt editing
if prompt_edit is not None:
tokens_cond_edit = clip_tokenizer(prompt_edit, padding='max_length',
max_length=clip_tokenizer.model_max_length,
truncation=True, return_tensors='pt',
return_overflowing_tokens=True
)
embedding_cond_edit = clip(tokens_cond_edit.input_ids.to(device)).last_hidden_state
c_a_c.init_attention_edit(tokens_cond, tokens_cond_edit)
c_a_c.init_attention_func()
c_a_c.init_attention_weights(prompt_edit_token_weights)
timesteps = scheduler.timesteps[t_start:]
for idx, timestep in tqdm(enumerate(timesteps), total=len(timesteps)):
t_index = t_start + idx
latent_model_input = latent
latent_model_input = scheduler.scale_model_input(latent_model_input, timestep)
# Predict the unconditional noise residual
noise_pred_uncond = unet(latent_model_input,
timestep,
encoder_hidden_states=embedding_uncond
).sample
# Prepare the Cross-Attention layers
if prompt_edit is not None:
c_a_c.save_last_tokens_attention()
c_a_c.save_last_self_attention()
else:
# Use weights on non-edited prompt when edit is None
c_a_c.use_last_tokens_attention_weights()
# Predict the conditional noise residual and save the
# cross-attention layer activations
noise_pred_cond = unet(latent_model_input,
timestep,
encoder_hidden_states=embedding_cond
).sample
# Edit the Cross-Attention layer activations
if prompt_edit is not None:
t_scale = timestep / scheduler.num_train_timesteps
if (t_scale >= prompt_edit_tokens_start
and t_scale <= prompt_edit_tokens_end):
c_a_c.use_last_tokens_attention()
if (t_scale >= prompt_edit_spatial_start
and t_scale <= prompt_edit_spatial_end):
c_a_c.use_last_self_attention()
# Use weights on edited prompt
c_a_c.use_last_tokens_attention_weights()
# Predict the edited conditional noise residual using the
# cross-attention masks
noise_pred_cond = unet(latent_model_input,
timestep,
encoder_hidden_states=embedding_cond_edit
).sample
# Perform guidance
noise_pred = (noise_pred_uncond + guidance_scale
* (noise_pred_cond - noise_pred_uncond))
latent = scheduler.step(noise_pred,
t_index,
latent
).prev_sample
# scale and decode the image latents with vae
latent = latent / 0.18215
image = vae.decode(latent.to(vae.dtype)).sample
image = (image / 2 + 0.5).clamp(0, 1)
image = image.cpu().permute(0, 2, 3, 1).numpy()
image = (image[0] * 255).round().astype('uint8')
return Image.fromarray(image)