"""SAMPLING ONLY."""
import torch
import numpy as np
from tqdm import tqdm
from ldm.modules.diffusionmodules.util import make_ddim_sampling_parameters, make_ddim_timesteps, noise_like, extract_into_tensor
import torch.nn.functional as F
import cv2
# Gaussian blur
def gaussian_blur_2d(img, kernel_size, sigma):
ksize_half = (kernel_size - 1) * 0.5
x = torch.linspace(-ksize_half, ksize_half, steps=kernel_size)
pdf = torch.exp(-0.5 * (x / sigma).pow(2))
x_kernel = pdf / pdf.sum()
x_kernel = x_kernel.to(device=img.device, dtype=img.dtype)
kernel2d = torch.mm(x_kernel[:, None], x_kernel[None, :])
kernel2d = kernel2d.expand(img.shape[-3], 1, kernel2d.shape[0], kernel2d.shape[1])
padding = [kernel_size // 2, kernel_size // 2, kernel_size // 2, kernel_size // 2]
img = F.pad(img, padding, mode="reflect")
img = F.conv2d(img, kernel2d, groups=img.shape[-3])
return img
# processes and stores attention probabilities
class CrossAttnStoreProcessor:
def __init__(self):
self.attention_probs = None
def __call__(
self,
attn,
hidden_states,
encoder_hidden_states=None,
attention_mask=None,
):
batch_size, sequence_length, _ = hidden_states.shape
attention_mask = attn.prepare_attention_mask(attention_mask, sequence_length, batch_size)
query = attn.to_q(hidden_states)
if encoder_hidden_states is None:
encoder_hidden_states = hidden_states
elif attn.norm_cross:
encoder_hidden_states = attn.norm_encoder_hidden_states(encoder_hidden_states)
key = attn.to_k(encoder_hidden_states)
value = attn.to_v(encoder_hidden_states)
query = attn.head_to_batch_dim(query)
key = attn.head_to_batch_dim(key)
value = attn.head_to_batch_dim(value)
self.attention_probs = attn.get_attention_scores(query, key, attention_mask)
hidden_states = torch.bmm(self.attention_probs, value)
hidden_states = attn.batch_to_head_dim(hidden_states)
# linear proj
hidden_states = attn.to_out[0](hidden_states)
# dropout
hidden_states = attn.to_out[1](hidden_states)
return hidden_states
class DDIMSampler(object):
def __init__(self, model, schedule="linear", **kwargs):
super().__init__()
self.model = model
self.ddpm_num_timesteps = model.num_timesteps
self.schedule = schedule
def register_buffer(self, name, attr):
if type(attr) == torch.Tensor:
if attr.device != torch.device("cuda"):
attr = attr.to(torch.device("cuda"))
setattr(self, name, attr)
def make_schedule(self, ddim_num_steps, ddim_discretize="uniform", ddim_eta=0., verbose=True):
self.ddim_timesteps = make_ddim_timesteps(ddim_discr_method=ddim_discretize, num_ddim_timesteps=ddim_num_steps,
num_ddpm_timesteps=self.ddpm_num_timesteps,verbose=verbose)
alphas_cumprod = self.model.alphas_cumprod
assert alphas_cumprod.shape[0] == self.ddpm_num_timesteps, 'alphas have to be defined for each timestep'
to_torch = lambda x: x.clone().detach().to(torch.float32).to(self.model.device)
self.register_buffer('betas', to_torch(self.model.betas))
self.register_buffer('alphas_cumprod', to_torch(alphas_cumprod))
self.register_buffer('alphas_cumprod_prev', to_torch(self.model.alphas_cumprod_prev))
# calculations for diffusion q(x_t | x_{t-1}) and others
self.register_buffer('sqrt_alphas_cumprod', to_torch(np.sqrt(alphas_cumprod.cpu())))
self.register_buffer('sqrt_one_minus_alphas_cumprod', to_torch(np.sqrt(1. - alphas_cumprod.cpu())))
self.register_buffer('log_one_minus_alphas_cumprod', to_torch(np.log(1. - alphas_cumprod.cpu())))
self.register_buffer('sqrt_recip_alphas_cumprod', to_torch(np.sqrt(1. / alphas_cumprod.cpu())))
self.register_buffer('sqrt_recipm1_alphas_cumprod', to_torch(np.sqrt(1. / alphas_cumprod.cpu() - 1)))
# ddim sampling parameters
ddim_sigmas, ddim_alphas, ddim_alphas_prev = make_ddim_sampling_parameters(alphacums=alphas_cumprod.cpu(),
ddim_timesteps=self.ddim_timesteps,
eta=ddim_eta,verbose=verbose)
self.register_buffer('ddim_sigmas', ddim_sigmas)
self.register_buffer('ddim_alphas', ddim_alphas)
self.register_buffer('ddim_alphas_prev', ddim_alphas_prev)
self.register_buffer('ddim_sqrt_one_minus_alphas', np.sqrt(1. - ddim_alphas))
sigmas_for_original_sampling_steps = ddim_eta * torch.sqrt(
(1 - self.alphas_cumprod_prev) / (1 - self.alphas_cumprod) * (
1 - self.alphas_cumprod / self.alphas_cumprod_prev))
self.register_buffer('ddim_sigmas_for_original_num_steps', sigmas_for_original_sampling_steps)
@torch.no_grad()
def sample(self,
S,
batch_size,
shape,
conditioning=None,
callback=None,
normals_sequence=None,
img_callback=None,
quantize_x0=False,
eta=0.,
mask=None,
masked_image_latents=None,
x0=None,
temperature=1.,
noise_dropout=0.,
score_corrector=None,
corrector_kwargs=None,
verbose=True,
x_T=None,
log_every_t=100,
unconditional_guidance_scale=1.,
sag_scale=0.75,
SAG_influence_step=600,
noise = None,
unconditional_conditioning=None, # this has to come in the same format as the conditioning, # e.g. as encoded tokens, ...
dynamic_threshold=None,
ucg_schedule=None,
**kwargs
):
if conditioning is not None:
if isinstance(conditioning, dict):
ctmp = conditioning[list(conditioning.keys())[0]]
while isinstance(ctmp, list): ctmp = ctmp[0]
cbs = ctmp.shape[0]
if cbs != batch_size:
print(f"Warning: Got {cbs} conditionings but batch-size is {batch_size}")
elif isinstance(conditioning, list):
for ctmp in conditioning:
if ctmp.shape[0] != batch_size:
print(f"Warning: Got {cbs} conditionings but batch-size is {batch_size}")
else:
if conditioning.shape[0] != batch_size:
print(f"Warning: Got {conditioning.shape[0]} conditionings but batch-size is {batch_size}")
self.make_schedule(ddim_num_steps=S, ddim_eta=eta, verbose=verbose)
# sampling
C, H, W = shape
size = (batch_size, C, H, W)
print(f'Data shape for DDIM sampling is {size}, eta {eta}')
samples, intermediates = self.ddim_sampling(conditioning, size,
callback=callback,
img_callback=img_callback,
quantize_denoised=quantize_x0,
mask=mask,masked_image_latents=masked_image_latents, x0=x0,
ddim_use_original_steps=False,
noise_dropout=noise_dropout,
temperature=temperature,
score_corrector=score_corrector,
corrector_kwargs=corrector_kwargs,
x_T=x_T,
log_every_t=log_every_t,
unconditional_guidance_scale=unconditional_guidance_scale,
sag_scale = sag_scale,
SAG_influence_step = SAG_influence_step,
noise = noise,
unconditional_conditioning=unconditional_conditioning,
dynamic_threshold=dynamic_threshold,
ucg_schedule=ucg_schedule
)
return samples, intermediates
def add_noise(self,
original_samples: torch.FloatTensor,
noise: torch.FloatTensor,
timesteps: torch.IntTensor,
) -> torch.FloatTensor:
betas = torch.linspace(0.00085, 0.0120, 1000, dtype=torch.float32)
alphas = 1.0 - betas
alphas_cumprod = torch.cumprod(alphas, dim=0)
alphas_cumprod = alphas_cumprod.to(device=original_samples.device, dtype=original_samples.dtype)
timesteps = timesteps.to(original_samples.device)
sqrt_alpha_prod = alphas_cumprod[timesteps] ** 0.5
sqrt_alpha_prod = sqrt_alpha_prod.flatten()
while len(sqrt_alpha_prod.shape) < len(original_samples.shape):
sqrt_alpha_prod = sqrt_alpha_prod.unsqueeze(-1)
sqrt_one_minus_alpha_prod = (1 - alphas_cumprod[timesteps]) ** 0.5
sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.flatten()
while len(sqrt_one_minus_alpha_prod.shape) < len(original_samples.shape):
sqrt_one_minus_alpha_prod = sqrt_one_minus_alpha_prod.unsqueeze(-1)
noisy_samples = sqrt_alpha_prod * original_samples + sqrt_one_minus_alpha_prod * noise
return noisy_samples
# def add_noise(
# self,
# original_samples: torch.FloatTensor,
# noise: torch.FloatTensor,
# timesteps: torch.FloatTensor,
# sigma_t,
# ) -> torch.FloatTensor:
# # Make sure sigmas and timesteps have the same device and dtype as original_samples
# sigmas = self.sigmas.to(device=original_samples.device, dtype=original_samples.dtype)
# if original_samples.device.type == "mps" and torch.is_floating_point(timesteps):
# # mps does not support float64
# schedule_timesteps = self.timesteps.to(original_samples.device, dtype=torch.float32)
# timesteps = timesteps.to(original_samples.device, dtype=torch.float32)
# else:
# schedule_timesteps = self.timesteps.to(original_samples.device)
# timesteps = timesteps.to(original_samples.device)
# step_indices = [(schedule_timesteps == t).nonzero().item() for t in timesteps]
# sigma = sigmas[step_indices].flatten()
# while len(sigma.shape) < len(original_samples.shape):
# sigma = sigma.unsqueeze(-1)
# # print(sigma_t)
# noisy_samples = original_samples + noise * sigma_t
# return noisy_samples
def sag_masking(self, original_latents,model_output,x, attn_map, map_size, t, eps):
# Same masking process as in SAG paper: https://arxiv.org/pdf/2210.00939.pdf
bh, hw1, hw2 = attn_map.shape
b, latent_channel, latent_h, latent_w = original_latents.shape
h = 4 #self.unet.config.attention_head_dim
if isinstance(h, list):
h = h[-1]
# print(attn_map.shape)
# print(original_latents.shape)
# print(map_size)
# Produce attention mask
attn_map = attn_map.reshape(b, h, hw1, hw2)
attn_mask = attn_map.mean(1, keepdim=False).sum(1, keepdim=False) > 1.0
# print(attn_mask.shape)
attn_mask = (
attn_mask.reshape(b, map_size[0], map_size[1])
.unsqueeze(1)
.repeat(1, latent_channel, 1, 1)
.type(attn_map.dtype)
)
attn_mask = F.interpolate(attn_mask, (latent_h, latent_w))
# print(attn_mask.shape)
# cv2.imwrite("attn_mask.png",attn_mask)
# Blur according to the self-attention mask
degraded_latents = gaussian_blur_2d(original_latents, kernel_size=9, sigma=1.0)
# degraded_latents = self.add_noise(degraded_latents, noise=eps, timesteps=t)#,sigma_t=sigma_t)
degraded_latents = degraded_latents * attn_mask + original_latents * (1 - attn_mask) #x#original_latents
# degraded_latents = self.model.get_x_t_from_start_and_t(degraded_latents,t,model_output)
# print(original_latents.shape)
# print(eps.shape)
# Noise it again to match the noise level
# print("t",t)
# degraded_latents = self.add_noise(degraded_latents, noise=eps, timesteps=t)#,sigma_t=sigma_t)
return degraded_latents
def pred_epsilon(self, sample, model_output, timestep):
alpha_prod_t = timestep
beta_prod_t = 1 - alpha_prod_t
# print(self.model.parameterization)#eps
if self.model.parameterization == "eps":
pred_eps = model_output
elif self.model.parameterization == "sample":
pred_eps = (sample - (alpha_prod_t**0.5) * model_output) / (beta_prod_t**0.5)
elif self.model.parameterization == "v":
pred_eps = (beta_prod_t**0.5) * sample + (alpha_prod_t**0.5) * model_output
else:
raise ValueError(
f"prediction_type given as {self.scheduler.config.prediction_type} must be one of `eps`, `sample`,"
" or `v`"
)
return pred_eps
@torch.no_grad()
def ddim_sampling(self, cond, shape,
x_T=None, ddim_use_original_steps=False,
callback=None, timesteps=None, quantize_denoised=False,
mask=None,masked_image_latents=None, x0=None, img_callback=None, log_every_t=100,
temperature=1., noise_dropout=0., score_corrector=None, corrector_kwargs=None,
unconditional_guidance_scale=1.,sag_scale = 0.75, SAG_influence_step=600, sag_enable = True, noise = None, unconditional_conditioning=None, dynamic_threshold=None,
ucg_schedule=None):
device = self.model.betas.device
b = shape[0]
if x_T is None:
img = torch.randn(shape, device=device)
else:
img = x_T
# timesteps =100
if timesteps is None:
timesteps = self.ddpm_num_timesteps if ddim_use_original_steps else self.ddim_timesteps
elif timesteps is not None and not ddim_use_original_steps:
subset_end = int(min(timesteps / self.ddim_timesteps.shape[0], 1) * self.ddim_timesteps.shape[0]) - 1
timesteps = self.ddim_timesteps[:subset_end]
# timesteps=timesteps[:-3]
# print("timesteps",timesteps)
intermediates = {'x_inter': [img], 'pred_x0': [img]}
time_range = reversed(range(0,timesteps)) if ddim_use_original_steps else np.flip(timesteps)
total_steps = timesteps if ddim_use_original_steps else timesteps.shape[0]
print(f"Running DDIM Sampling with {total_steps} timesteps")
iterator = tqdm(time_range, desc='DDIM Sampler', total=total_steps)
for i, step in enumerate(iterator):
print(step)
if step > SAG_influence_step:
sag_enable_t=True
else:
sag_enable_t=False
index = total_steps - i - 1
ts = torch.full((b,), step, device=device, dtype=torch.long)
# if mask is not None:
# assert x0 is not None
# img_orig = self.model.q_sample(x0, ts) # TODO: deterministic forward pass?
# img = img_orig * mask + (1. - mask) * img
if ucg_schedule is not None:
assert len(ucg_schedule) == len(time_range)
unconditional_guidance_scale = ucg_schedule[i]
outs = self.p_sample_ddim(img,mask,masked_image_latents, cond, ts, index=index, use_original_steps=ddim_use_original_steps,
quantize_denoised=quantize_denoised, temperature=temperature,
noise_dropout=noise_dropout, score_corrector=score_corrector,
corrector_kwargs=corrector_kwargs,
unconditional_guidance_scale=unconditional_guidance_scale,
sag_scale = sag_scale,
sag_enable=sag_enable_t,
noise =noise,
unconditional_conditioning=unconditional_conditioning,
dynamic_threshold=dynamic_threshold)
img, pred_x0 = outs
if callback: callback(i)
if img_callback: img_callback(pred_x0, i)
if index % log_every_t == 0 or index == total_steps - 1:
intermediates['x_inter'].append(img)
intermediates['pred_x0'].append(pred_x0)
return img, intermediates
@torch.no_grad()
def p_sample_ddim(self, x,mask,masked_image_latents, c, t, index, repeat_noise=False, use_original_steps=False, quantize_denoised=False,
temperature=1., noise_dropout=0., score_corrector=None, corrector_kwargs=None,
unconditional_guidance_scale=1.,sag_scale = 0.75, sag_enable=True, noise=None, unconditional_conditioning=None,
dynamic_threshold=None):
b, *_, device = *x.shape, x.device
# map_size = None
# def get_map_size(module, input, output):
# nonlocal map_size
# map_size = output.shape[-2:]
# store_processor = CrossAttnStoreProcessor()
# for name, param in self.model.model.diffusion_model.named_parameters():
# print(name)
# self.model.control_model.middle_block[1].transformer_blocks[0].attn1.processor = store_processor
# print(self.model.model.diffusion_model.middle_block[1].transformer_blocks[0].attn1)
# self.model.model.diffusion_model.middle_block[1].transformer_blocks[0].attn1 = store_processor
# with self.model.model.diffusion_model.middle_block[1].register_forward_hook(get_map_size):
if unconditional_conditioning is None or unconditional_guidance_scale == 1.:
model_output = self.model.apply_model(x,mask,masked_image_latents, t, c)
else:
model_t = self.model.apply_model(x,mask,masked_image_latents, t, c)
model_uncond = self.model.apply_model(x,mask,masked_image_latents, t, unconditional_conditioning)
model_output = model_uncond + unconditional_guidance_scale * (model_t - model_uncond)
if self.model.parameterization == "v":
e_t = self.model.predict_eps_from_z_and_v(x, t, model_output)
else:
e_t = model_output
if score_corrector is not None:
assert self.model.parameterization == "eps", 'not implemented'
e_t = score_corrector.modify_score(self.model, e_t, x, t, c, **corrector_kwargs)
alphas = self.model.alphas_cumprod if use_original_steps else self.ddim_alphas
alphas_prev = self.model.alphas_cumprod_prev if use_original_steps else self.ddim_alphas_prev
sqrt_one_minus_alphas = self.model.sqrt_one_minus_alphas_cumprod if use_original_steps else self.ddim_sqrt_one_minus_alphas
sigmas = self.model.ddim_sigmas_for_original_num_steps if use_original_steps else self.ddim_sigmas
# select parameters corresponding to the currently considered timestep
a_t = torch.full((b, 1, 1, 1), alphas[index], device=device)
a_prev = torch.full((b, 1, 1, 1), alphas_prev[index], device=device)
sigma_t = torch.full((b, 1, 1, 1), sigmas[index], device=device)
sqrt_one_minus_at = torch.full((b, 1, 1, 1), sqrt_one_minus_alphas[index],device=device)
# current prediction for x_0
if self.model.parameterization != "v":
pred_x0 = (x - sqrt_one_minus_at * e_t) / a_t.sqrt()
else:
pred_x0 = self.model.predict_start_from_z_and_v(x, t, model_output)
if quantize_denoised:
pred_x0, _, *_ = self.model.first_stage_model.quantize(pred_x0)
if dynamic_threshold is not None:
raise NotImplementedError()
if sag_enable == True:
uncond_attn, cond_attn = self.model.model.diffusion_model.middle_block[1].transformer_blocks[0].attn1.attention_probs.chunk(2)
# self-attention-based degrading of latents
map_size = self.model.model.diffusion_model.middle_block[1].map_size
degraded_latents = self.sag_masking(
pred_x0,model_output,x,uncond_attn, map_size, t, eps = noise, #self.pred_epsilon(x, model_uncond, self.model.alphas_cumprod[t]),#noise
)
if unconditional_conditioning is None or unconditional_guidance_scale == 1.:
degraded_model_output = self.model.apply_model(degraded_latents,mask,masked_image_latents, t, c)
else:
degraded_model_t = self.model.apply_model(degraded_latents,mask,masked_image_latents, t, c)
degraded_model_uncond = self.model.apply_model(degraded_latents,mask,masked_image_latents, t, unconditional_conditioning)
degraded_model_output = degraded_model_uncond + unconditional_guidance_scale * (degraded_model_t - degraded_model_uncond)
# print("sag_scale",sag_scale)
model_output += sag_scale * (model_output - degraded_model_output)
# model_output = (1-sag_scale) * model_output + sag_scale * degraded_model_output
# current prediction for x_0
if self.model.parameterization != "v":
pred_x0 = (x - sqrt_one_minus_at * e_t) / a_t.sqrt()
else:
pred_x0 = self.model.predict_start_from_z_and_v(x, t, model_output)
if quantize_denoised:
pred_x0, _, *_ = self.model.first_stage_model.quantize(pred_x0)
if dynamic_threshold is not None:
raise NotImplementedError()
# direction pointing to x_t
dir_xt = (1. - a_prev - sigma_t**2).sqrt() * e_t
noise = sigma_t * noise_like(x.shape, device, repeat_noise) * temperature
if noise_dropout > 0.:
noise = torch.nn.functional.dropout(noise, p=noise_dropout)
x_prev = a_prev.sqrt() * pred_x0 + dir_xt + noise
return x_prev, pred_x0
@torch.no_grad()
def encode(self, x0, c, t_enc, use_original_steps=False, return_intermediates=None,
unconditional_guidance_scale=1.0, unconditional_conditioning=None, callback=None):
timesteps = np.arange(self.ddpm_num_timesteps) if use_original_steps else self.ddim_timesteps
num_reference_steps = timesteps.shape[0]
assert t_enc <= num_reference_steps
num_steps = t_enc
if use_original_steps:
alphas_next = self.alphas_cumprod[:num_steps]
alphas = self.alphas_cumprod_prev[:num_steps]
else:
alphas_next = self.ddim_alphas[:num_steps]
alphas = torch.tensor(self.ddim_alphas_prev[:num_steps])
x_next = x0
intermediates = []
inter_steps = []
for i in tqdm(range(num_steps), desc='Encoding Image'):
t = torch.full((x0.shape[0],), timesteps[i], device=self.model.device, dtype=torch.long)
if unconditional_guidance_scale == 1.:
noise_pred = self.model.apply_model(x_next, t, c)
else:
assert unconditional_conditioning is not None
e_t_uncond, noise_pred = torch.chunk(
self.model.apply_model(torch.cat((x_next, x_next)), torch.cat((t, t)),
torch.cat((unconditional_conditioning, c))), 2)
noise_pred = e_t_uncond + unconditional_guidance_scale * (noise_pred - e_t_uncond)
xt_weighted = (alphas_next[i] / alphas[i]).sqrt() * x_next
weighted_noise_pred = alphas_next[i].sqrt() * (
(1 / alphas_next[i] - 1).sqrt() - (1 / alphas[i] - 1).sqrt()) * noise_pred
x_next = xt_weighted + weighted_noise_pred
if return_intermediates and i % (
num_steps // return_intermediates) == 0 and i < num_steps - 1:
intermediates.append(x_next)
inter_steps.append(i)
elif return_intermediates and i >= num_steps - 2:
intermediates.append(x_next)
inter_steps.append(i)
if callback: callback(i)
out = {'x_encoded': x_next, 'intermediate_steps': inter_steps}
if return_intermediates:
out.update({'intermediates': intermediates})
return x_next, out
@torch.no_grad()
def stochastic_encode(self, x0, t, use_original_steps=False, noise=None):
# fast, but does not allow for exact reconstruction
# t serves as an index to gather the correct alphas
if use_original_steps:
sqrt_alphas_cumprod = self.sqrt_alphas_cumprod
sqrt_one_minus_alphas_cumprod = self.sqrt_one_minus_alphas_cumprod
else:
sqrt_alphas_cumprod = torch.sqrt(self.ddim_alphas)
sqrt_one_minus_alphas_cumprod = self.ddim_sqrt_one_minus_alphas
if noise is None:
noise = torch.randn_like(x0)
return (extract_into_tensor(sqrt_alphas_cumprod, t, x0.shape) * x0 +
extract_into_tensor(sqrt_one_minus_alphas_cumprod, t, x0.shape) * noise)
@torch.no_grad()
def decode(self, x_latent, cond, t_start, unconditional_guidance_scale=1.0, unconditional_conditioning=None,
use_original_steps=False, callback=None):
timesteps = np.arange(self.ddpm_num_timesteps) if use_original_steps else self.ddim_timesteps
timesteps = timesteps[:t_start]
time_range = np.flip(timesteps)
total_steps = timesteps.shape[0]
print(f"Running DDIM Sampling with {total_steps} timesteps")
iterator = tqdm(time_range, desc='Decoding image', total=total_steps)
x_dec = x_latent
for i, step in enumerate(iterator):
index = total_steps - i - 1
ts = torch.full((x_latent.shape[0],), step, device=x_latent.device, dtype=torch.long)
x_dec, _ = self.p_sample_ddim(x_dec, cond, ts, index=index, use_original_steps=use_original_steps,
unconditional_guidance_scale=unconditional_guidance_scale,
unconditional_conditioning=unconditional_conditioning)
if callback: callback(i)
return x_dec