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DDIM is the same as euler with a small difference in the inpaint code. DDIM uses randn_like but I set a fixed seed instead. I'm keeping it in because I'm sure if I remove it people are going to complain.pull/1882/head
comfyanonymous
1 year ago
8 changed files with 7 additions and 1985 deletions
@ -1,418 +0,0 @@
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"""SAMPLING ONLY.""" |
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import torch |
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import numpy as np |
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from tqdm import tqdm |
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from comfy.ldm.modules.diffusionmodules.util import make_ddim_sampling_parameters, make_ddim_timesteps, noise_like, extract_into_tensor |
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class DDIMSampler(object): |
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def __init__(self, model, schedule="linear", device=torch.device("cuda"), **kwargs): |
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super().__init__() |
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self.model = model |
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self.ddpm_num_timesteps = model.num_timesteps |
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self.schedule = schedule |
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self.device = device |
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self.parameterization = kwargs.get("parameterization", "eps") |
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def register_buffer(self, name, attr): |
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if type(attr) == torch.Tensor: |
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if attr.device != self.device: |
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attr = attr.float().to(self.device) |
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setattr(self, name, attr) |
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def make_schedule(self, ddim_num_steps, ddim_discretize="uniform", ddim_eta=0., verbose=True): |
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ddim_timesteps = make_ddim_timesteps(ddim_discr_method=ddim_discretize, num_ddim_timesteps=ddim_num_steps, |
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num_ddpm_timesteps=self.ddpm_num_timesteps,verbose=verbose) |
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self.make_schedule_timesteps(ddim_timesteps, ddim_eta=ddim_eta, verbose=verbose) |
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def make_schedule_timesteps(self, ddim_timesteps, ddim_eta=0., verbose=True): |
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self.ddim_timesteps = torch.tensor(ddim_timesteps) |
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alphas_cumprod = self.model.alphas_cumprod |
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assert alphas_cumprod.shape[0] == self.ddpm_num_timesteps, 'alphas have to be defined for each timestep' |
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to_torch = lambda x: x.clone().detach().to(torch.float32).to(self.device) |
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self.register_buffer('alphas_cumprod', to_torch(alphas_cumprod)) |
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self.register_buffer('alphas_cumprod_prev', to_torch(self.model.alphas_cumprod_prev)) |
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# calculations for diffusion q(x_t | x_{t-1}) and others |
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self.register_buffer('sqrt_alphas_cumprod', to_torch(np.sqrt(alphas_cumprod.cpu()))) |
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self.register_buffer('sqrt_one_minus_alphas_cumprod', to_torch(np.sqrt(1. - alphas_cumprod.cpu()))) |
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self.register_buffer('log_one_minus_alphas_cumprod', to_torch(np.log(1. - alphas_cumprod.cpu()))) |
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self.register_buffer('sqrt_recip_alphas_cumprod', to_torch(np.sqrt(1. / alphas_cumprod.cpu()))) |
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self.register_buffer('sqrt_recipm1_alphas_cumprod', to_torch(np.sqrt(1. / alphas_cumprod.cpu() - 1))) |
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# ddim sampling parameters |
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ddim_sigmas, ddim_alphas, ddim_alphas_prev = make_ddim_sampling_parameters(alphacums=alphas_cumprod.cpu(), |
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ddim_timesteps=self.ddim_timesteps, |
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eta=ddim_eta,verbose=verbose) |
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self.register_buffer('ddim_sigmas', ddim_sigmas) |
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self.register_buffer('ddim_alphas', ddim_alphas) |
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self.register_buffer('ddim_alphas_prev', ddim_alphas_prev) |
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self.register_buffer('ddim_sqrt_one_minus_alphas', np.sqrt(1. - ddim_alphas)) |
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sigmas_for_original_sampling_steps = ddim_eta * torch.sqrt( |
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(1 - self.alphas_cumprod_prev) / (1 - self.alphas_cumprod) * ( |
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1 - self.alphas_cumprod / self.alphas_cumprod_prev)) |
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self.register_buffer('ddim_sigmas_for_original_num_steps', sigmas_for_original_sampling_steps) |
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@torch.no_grad() |
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def sample_custom(self, |
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ddim_timesteps, |
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conditioning=None, |
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callback=None, |
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img_callback=None, |
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quantize_x0=False, |
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eta=0., |
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mask=None, |
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x0=None, |
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temperature=1., |
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noise_dropout=0., |
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score_corrector=None, |
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corrector_kwargs=None, |
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verbose=True, |
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x_T=None, |
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log_every_t=100, |
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unconditional_guidance_scale=1., |
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unconditional_conditioning=None, # this has to come in the same format as the conditioning, # e.g. as encoded tokens, ... |
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dynamic_threshold=None, |
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ucg_schedule=None, |
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denoise_function=None, |
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extra_args=None, |
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to_zero=True, |
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end_step=None, |
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disable_pbar=False, |
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**kwargs |
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): |
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self.make_schedule_timesteps(ddim_timesteps=ddim_timesteps, ddim_eta=eta, verbose=verbose) |
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samples, intermediates = self.ddim_sampling(conditioning, x_T.shape, |
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callback=callback, |
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img_callback=img_callback, |
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quantize_denoised=quantize_x0, |
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mask=mask, x0=x0, |
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ddim_use_original_steps=False, |
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noise_dropout=noise_dropout, |
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temperature=temperature, |
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score_corrector=score_corrector, |
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corrector_kwargs=corrector_kwargs, |
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x_T=x_T, |
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log_every_t=log_every_t, |
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unconditional_guidance_scale=unconditional_guidance_scale, |
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unconditional_conditioning=unconditional_conditioning, |
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dynamic_threshold=dynamic_threshold, |
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ucg_schedule=ucg_schedule, |
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denoise_function=denoise_function, |
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extra_args=extra_args, |
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to_zero=to_zero, |
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end_step=end_step, |
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disable_pbar=disable_pbar |
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) |
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return samples, intermediates |
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@torch.no_grad() |
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def sample(self, |
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S, |
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batch_size, |
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shape, |
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conditioning=None, |
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callback=None, |
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normals_sequence=None, |
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img_callback=None, |
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quantize_x0=False, |
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eta=0., |
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mask=None, |
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x0=None, |
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temperature=1., |
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noise_dropout=0., |
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score_corrector=None, |
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corrector_kwargs=None, |
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verbose=True, |
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x_T=None, |
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log_every_t=100, |
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unconditional_guidance_scale=1., |
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unconditional_conditioning=None, # this has to come in the same format as the conditioning, # e.g. as encoded tokens, ... |
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dynamic_threshold=None, |
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ucg_schedule=None, |
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**kwargs |
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): |
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if conditioning is not None: |
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if isinstance(conditioning, dict): |
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ctmp = conditioning[list(conditioning.keys())[0]] |
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while isinstance(ctmp, list): ctmp = ctmp[0] |
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cbs = ctmp.shape[0] |
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if cbs != batch_size: |
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print(f"Warning: Got {cbs} conditionings but batch-size is {batch_size}") |
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elif isinstance(conditioning, list): |
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for ctmp in conditioning: |
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if ctmp.shape[0] != batch_size: |
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print(f"Warning: Got {cbs} conditionings but batch-size is {batch_size}") |
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else: |
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if conditioning.shape[0] != batch_size: |
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print(f"Warning: Got {conditioning.shape[0]} conditionings but batch-size is {batch_size}") |
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self.make_schedule(ddim_num_steps=S, ddim_eta=eta, verbose=verbose) |
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# sampling |
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C, H, W = shape |
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size = (batch_size, C, H, W) |
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print(f'Data shape for DDIM sampling is {size}, eta {eta}') |
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samples, intermediates = self.ddim_sampling(conditioning, size, |
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callback=callback, |
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img_callback=img_callback, |
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quantize_denoised=quantize_x0, |
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mask=mask, x0=x0, |
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ddim_use_original_steps=False, |
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noise_dropout=noise_dropout, |
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temperature=temperature, |
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score_corrector=score_corrector, |
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corrector_kwargs=corrector_kwargs, |
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x_T=x_T, |
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log_every_t=log_every_t, |
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unconditional_guidance_scale=unconditional_guidance_scale, |
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unconditional_conditioning=unconditional_conditioning, |
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dynamic_threshold=dynamic_threshold, |
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ucg_schedule=ucg_schedule, |
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denoise_function=None, |
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extra_args=None |
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) |
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return samples, intermediates |
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def q_sample(self, x_start, t, noise=None): |
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if noise is None: |
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noise = torch.randn_like(x_start) |
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return (extract_into_tensor(self.sqrt_alphas_cumprod, t, x_start.shape) * x_start + |
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extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x_start.shape) * noise) |
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@torch.no_grad() |
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def ddim_sampling(self, cond, shape, |
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x_T=None, ddim_use_original_steps=False, |
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callback=None, timesteps=None, quantize_denoised=False, |
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mask=None, x0=None, img_callback=None, log_every_t=100, |
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temperature=1., noise_dropout=0., score_corrector=None, corrector_kwargs=None, |
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unconditional_guidance_scale=1., unconditional_conditioning=None, dynamic_threshold=None, |
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ucg_schedule=None, denoise_function=None, extra_args=None, to_zero=True, end_step=None, disable_pbar=False): |
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device = self.model.alphas_cumprod.device |
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b = shape[0] |
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if x_T is None: |
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img = torch.randn(shape, device=device) |
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else: |
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img = x_T |
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if timesteps is None: |
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timesteps = self.ddpm_num_timesteps if ddim_use_original_steps else self.ddim_timesteps |
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elif timesteps is not None and not ddim_use_original_steps: |
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subset_end = int(min(timesteps / self.ddim_timesteps.shape[0], 1) * self.ddim_timesteps.shape[0]) - 1 |
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timesteps = self.ddim_timesteps[:subset_end] |
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intermediates = {'x_inter': [img], 'pred_x0': [img]} |
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time_range = reversed(range(0,timesteps)) if ddim_use_original_steps else timesteps.flip(0) |
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total_steps = timesteps if ddim_use_original_steps else timesteps.shape[0] |
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# print(f"Running DDIM Sampling with {total_steps} timesteps") |
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iterator = tqdm(time_range[:end_step], desc='DDIM Sampler', total=end_step, disable=disable_pbar) |
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for i, step in enumerate(iterator): |
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index = total_steps - i - 1 |
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ts = torch.full((b,), step, device=device, dtype=torch.long) |
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if mask is not None: |
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assert x0 is not None |
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img_orig = self.q_sample(x0, ts) # TODO: deterministic forward pass? |
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img = img_orig * mask + (1. - mask) * img |
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if ucg_schedule is not None: |
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assert len(ucg_schedule) == len(time_range) |
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unconditional_guidance_scale = ucg_schedule[i] |
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outs = self.p_sample_ddim(img, cond, ts, index=index, use_original_steps=ddim_use_original_steps, |
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quantize_denoised=quantize_denoised, temperature=temperature, |
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noise_dropout=noise_dropout, score_corrector=score_corrector, |
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corrector_kwargs=corrector_kwargs, |
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unconditional_guidance_scale=unconditional_guidance_scale, |
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unconditional_conditioning=unconditional_conditioning, |
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dynamic_threshold=dynamic_threshold, denoise_function=denoise_function, extra_args=extra_args) |
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img, pred_x0 = outs |
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if callback: callback(i) |
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if img_callback: img_callback(pred_x0, i) |
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if index % log_every_t == 0 or index == total_steps - 1: |
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intermediates['x_inter'].append(img) |
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intermediates['pred_x0'].append(pred_x0) |
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if to_zero: |
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img = pred_x0 |
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else: |
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if ddim_use_original_steps: |
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sqrt_alphas_cumprod = self.sqrt_alphas_cumprod |
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else: |
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sqrt_alphas_cumprod = torch.sqrt(self.ddim_alphas) |
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img /= sqrt_alphas_cumprod[index - 1] |
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return img, intermediates |
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@torch.no_grad() |
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def p_sample_ddim(self, x, c, t, index, repeat_noise=False, use_original_steps=False, quantize_denoised=False, |
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temperature=1., noise_dropout=0., score_corrector=None, corrector_kwargs=None, |
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unconditional_guidance_scale=1., unconditional_conditioning=None, |
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dynamic_threshold=None, denoise_function=None, extra_args=None): |
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b, *_, device = *x.shape, x.device |
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if denoise_function is not None: |
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model_output = denoise_function(x, t, **extra_args) |
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elif unconditional_conditioning is None or unconditional_guidance_scale == 1.: |
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model_output = self.model.apply_model(x, t, c) |
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else: |
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x_in = torch.cat([x] * 2) |
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t_in = torch.cat([t] * 2) |
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if isinstance(c, dict): |
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assert isinstance(unconditional_conditioning, dict) |
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c_in = dict() |
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for k in c: |
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if isinstance(c[k], list): |
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c_in[k] = [torch.cat([ |
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unconditional_conditioning[k][i], |
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c[k][i]]) for i in range(len(c[k]))] |
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else: |
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c_in[k] = torch.cat([ |
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unconditional_conditioning[k], |
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c[k]]) |
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elif isinstance(c, list): |
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c_in = list() |
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assert isinstance(unconditional_conditioning, list) |
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for i in range(len(c)): |
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c_in.append(torch.cat([unconditional_conditioning[i], c[i]])) |
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else: |
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c_in = torch.cat([unconditional_conditioning, c]) |
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model_uncond, model_t = self.model.apply_model(x_in, t_in, c_in).chunk(2) |
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model_output = model_uncond + unconditional_guidance_scale * (model_t - model_uncond) |
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if self.parameterization == "v": |
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e_t = extract_into_tensor(self.sqrt_alphas_cumprod, t, x.shape) * model_output + extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x.shape) * x |
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else: |
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e_t = model_output |
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if score_corrector is not None: |
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assert self.parameterization == "eps", 'not implemented' |
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e_t = score_corrector.modify_score(self.model, e_t, x, t, c, **corrector_kwargs) |
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alphas = self.model.alphas_cumprod if use_original_steps else self.ddim_alphas |
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alphas_prev = self.model.alphas_cumprod_prev if use_original_steps else self.ddim_alphas_prev |
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sqrt_one_minus_alphas = self.model.sqrt_one_minus_alphas_cumprod if use_original_steps else self.ddim_sqrt_one_minus_alphas |
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sigmas = self.model.ddim_sigmas_for_original_num_steps if use_original_steps else self.ddim_sigmas |
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# select parameters corresponding to the currently considered timestep |
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a_t = torch.full((b, 1, 1, 1), alphas[index], device=device) |
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a_prev = torch.full((b, 1, 1, 1), alphas_prev[index], device=device) |
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sigma_t = torch.full((b, 1, 1, 1), sigmas[index], device=device) |
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sqrt_one_minus_at = torch.full((b, 1, 1, 1), sqrt_one_minus_alphas[index],device=device) |
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# current prediction for x_0 |
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if self.parameterization != "v": |
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pred_x0 = (x - sqrt_one_minus_at * e_t) / a_t.sqrt() |
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else: |
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pred_x0 = extract_into_tensor(self.sqrt_alphas_cumprod, t, x.shape) * x - extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x.shape) * model_output |
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if quantize_denoised: |
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pred_x0, _, *_ = self.model.first_stage_model.quantize(pred_x0) |
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if dynamic_threshold is not None: |
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raise NotImplementedError() |
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# direction pointing to x_t |
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dir_xt = (1. - a_prev - sigma_t**2).sqrt() * e_t |
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noise = sigma_t * noise_like(x.shape, device, repeat_noise) * temperature |
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if noise_dropout > 0.: |
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noise = torch.nn.functional.dropout(noise, p=noise_dropout) |
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x_prev = a_prev.sqrt() * pred_x0 + dir_xt + noise |
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return x_prev, pred_x0 |
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@torch.no_grad() |
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def encode(self, x0, c, t_enc, use_original_steps=False, return_intermediates=None, |
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unconditional_guidance_scale=1.0, unconditional_conditioning=None, callback=None): |
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num_reference_steps = self.ddpm_num_timesteps if use_original_steps else self.ddim_timesteps.shape[0] |
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assert t_enc <= num_reference_steps |
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num_steps = t_enc |
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if use_original_steps: |
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alphas_next = self.alphas_cumprod[:num_steps] |
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alphas = self.alphas_cumprod_prev[:num_steps] |
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else: |
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alphas_next = self.ddim_alphas[:num_steps] |
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alphas = torch.tensor(self.ddim_alphas_prev[:num_steps]) |
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x_next = x0 |
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intermediates = [] |
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inter_steps = [] |
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for i in tqdm(range(num_steps), desc='Encoding Image'): |
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t = torch.full((x0.shape[0],), i, device=self.model.device, dtype=torch.long) |
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if unconditional_guidance_scale == 1.: |
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noise_pred = self.model.apply_model(x_next, t, c) |
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else: |
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assert unconditional_conditioning is not None |
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e_t_uncond, noise_pred = torch.chunk( |
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self.model.apply_model(torch.cat((x_next, x_next)), torch.cat((t, t)), |
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torch.cat((unconditional_conditioning, c))), 2) |
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noise_pred = e_t_uncond + unconditional_guidance_scale * (noise_pred - e_t_uncond) |
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xt_weighted = (alphas_next[i] / alphas[i]).sqrt() * x_next |
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weighted_noise_pred = alphas_next[i].sqrt() * ( |
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(1 / alphas_next[i] - 1).sqrt() - (1 / alphas[i] - 1).sqrt()) * noise_pred |
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x_next = xt_weighted + weighted_noise_pred |
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if return_intermediates and i % ( |
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num_steps // return_intermediates) == 0 and i < num_steps - 1: |
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intermediates.append(x_next) |
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inter_steps.append(i) |
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elif return_intermediates and i >= num_steps - 2: |
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intermediates.append(x_next) |
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inter_steps.append(i) |
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if callback: callback(i) |
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out = {'x_encoded': x_next, 'intermediate_steps': inter_steps} |
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if return_intermediates: |
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out.update({'intermediates': intermediates}) |
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return x_next, out |
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@torch.no_grad() |
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def stochastic_encode(self, x0, t, use_original_steps=False, noise=None, max_denoise=False): |
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# fast, but does not allow for exact reconstruction |
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# t serves as an index to gather the correct alphas |
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if use_original_steps: |
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sqrt_alphas_cumprod = self.sqrt_alphas_cumprod |
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sqrt_one_minus_alphas_cumprod = self.sqrt_one_minus_alphas_cumprod |
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else: |
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sqrt_alphas_cumprod = torch.sqrt(self.ddim_alphas) |
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sqrt_one_minus_alphas_cumprod = self.ddim_sqrt_one_minus_alphas |
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if noise is None: |
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noise = torch.randn_like(x0) |
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if max_denoise: |
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noise_multiplier = 1.0 |
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else: |
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noise_multiplier = extract_into_tensor(sqrt_one_minus_alphas_cumprod, t, x0.shape) |
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return (extract_into_tensor(sqrt_alphas_cumprod, t, x0.shape) * x0 + noise_multiplier * noise) |
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@torch.no_grad() |
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def decode(self, x_latent, cond, t_start, unconditional_guidance_scale=1.0, unconditional_conditioning=None, |
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use_original_steps=False, callback=None): |
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timesteps = np.arange(self.ddpm_num_timesteps) if use_original_steps else self.ddim_timesteps |
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timesteps = timesteps[:t_start] |
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time_range = np.flip(timesteps) |
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total_steps = timesteps.shape[0] |
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print(f"Running DDIM Sampling with {total_steps} timesteps") |
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iterator = tqdm(time_range, desc='Decoding image', total=total_steps) |
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x_dec = x_latent |
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for i, step in enumerate(iterator): |
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index = total_steps - i - 1 |
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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 |
@ -1 +0,0 @@
|
||||
from .sampler import DPMSolverSampler |
File diff suppressed because it is too large
Load Diff
@ -1,96 +0,0 @@
|
||||
"""SAMPLING ONLY.""" |
||||
import torch |
||||
|
||||
from .dpm_solver import NoiseScheduleVP, model_wrapper, DPM_Solver |
||||
|
||||
MODEL_TYPES = { |
||||
"eps": "noise", |
||||
"v": "v" |
||||
} |
||||
|
||||
|
||||
class DPMSolverSampler(object): |
||||
def __init__(self, model, device=torch.device("cuda"), **kwargs): |
||||
super().__init__() |
||||
self.model = model |
||||
self.device = device |
||||
to_torch = lambda x: x.clone().detach().to(torch.float32).to(model.device) |
||||
self.register_buffer('alphas_cumprod', to_torch(model.alphas_cumprod)) |
||||
|
||||
def register_buffer(self, name, attr): |
||||
if type(attr) == torch.Tensor: |
||||
if attr.device != self.device: |
||||
attr = attr.to(self.device) |
||||
setattr(self, name, attr) |
||||
|
||||
@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, |
||||
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., |
||||
unconditional_conditioning=None, |
||||
# this has to come in the same format as the conditioning, # e.g. as encoded tokens, ... |
||||
**kwargs |
||||
): |
||||
if conditioning is not None: |
||||
if isinstance(conditioning, dict): |
||||
ctmp = conditioning[list(conditioning.keys())[0]] |
||||
while isinstance(ctmp, list): ctmp = ctmp[0] |
||||
if isinstance(ctmp, torch.Tensor): |
||||
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 {ctmp.shape[0]} conditionings but batch-size is {batch_size}") |
||||
else: |
||||
if isinstance(conditioning, torch.Tensor): |
||||
if conditioning.shape[0] != batch_size: |
||||
print(f"Warning: Got {conditioning.shape[0]} conditionings but batch-size is {batch_size}") |
||||
|
||||
# sampling |
||||
C, H, W = shape |
||||
size = (batch_size, C, H, W) |
||||
|
||||
print(f'Data shape for DPM-Solver sampling is {size}, sampling steps {S}') |
||||
|
||||
device = self.model.betas.device |
||||
if x_T is None: |
||||
img = torch.randn(size, device=device) |
||||
else: |
||||
img = x_T |
||||
|
||||
ns = NoiseScheduleVP('discrete', alphas_cumprod=self.alphas_cumprod) |
||||
|
||||
model_fn = model_wrapper( |
||||
lambda x, t, c: self.model.apply_model(x, t, c), |
||||
ns, |
||||
model_type=MODEL_TYPES[self.model.parameterization], |
||||
guidance_type="classifier-free", |
||||
condition=conditioning, |
||||
unconditional_condition=unconditional_conditioning, |
||||
guidance_scale=unconditional_guidance_scale, |
||||
) |
||||
|
||||
dpm_solver = DPM_Solver(model_fn, ns, predict_x0=True, thresholding=False) |
||||
x = dpm_solver.sample(img, steps=S, skip_type="time_uniform", method="multistep", order=2, |
||||
lower_order_final=True) |
||||
|
||||
return x.to(device), None |
@ -1,245 +0,0 @@
|
||||
"""SAMPLING ONLY.""" |
||||
|
||||
import torch |
||||
import numpy as np |
||||
from tqdm import tqdm |
||||
from functools import partial |
||||
|
||||
from ldm.modules.diffusionmodules.util import make_ddim_sampling_parameters, make_ddim_timesteps, noise_like |
||||
from ldm.models.diffusion.sampling_util import norm_thresholding |
||||
|
||||
|
||||
class PLMSSampler(object): |
||||
def __init__(self, model, schedule="linear", device=torch.device("cuda"), **kwargs): |
||||
super().__init__() |
||||
self.model = model |
||||
self.ddpm_num_timesteps = model.num_timesteps |
||||
self.schedule = schedule |
||||
self.device = device |
||||
|
||||
def register_buffer(self, name, attr): |
||||
if type(attr) == torch.Tensor: |
||||
if attr.device != self.device: |
||||
attr = attr.to(self.device) |
||||
setattr(self, name, attr) |
||||
|
||||
def make_schedule(self, ddim_num_steps, ddim_discretize="uniform", ddim_eta=0., verbose=True): |
||||
if ddim_eta != 0: |
||||
raise ValueError('ddim_eta must be 0 for PLMS') |
||||
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, |
||||
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., |
||||
unconditional_conditioning=None, |
||||
# this has to come in the same format as the conditioning, # e.g. as encoded tokens, ... |
||||
dynamic_threshold=None, |
||||
**kwargs |
||||
): |
||||
if conditioning is not None: |
||||
if isinstance(conditioning, dict): |
||||
cbs = conditioning[list(conditioning.keys())[0]].shape[0] |
||||
if cbs != 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 PLMS sampling is {size}') |
||||
|
||||
samples, intermediates = self.plms_sampling(conditioning, size, |
||||
callback=callback, |
||||
img_callback=img_callback, |
||||
quantize_denoised=quantize_x0, |
||||
mask=mask, 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, |
||||
unconditional_conditioning=unconditional_conditioning, |
||||
dynamic_threshold=dynamic_threshold, |
||||
) |
||||
return samples, intermediates |
||||
|
||||
@torch.no_grad() |
||||
def plms_sampling(self, cond, shape, |
||||
x_T=None, ddim_use_original_steps=False, |
||||
callback=None, timesteps=None, quantize_denoised=False, |
||||
mask=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., unconditional_conditioning=None, |
||||
dynamic_threshold=None): |
||||
device = self.model.betas.device |
||||
b = shape[0] |
||||
if x_T is None: |
||||
img = torch.randn(shape, device=device) |
||||
else: |
||||
img = x_T |
||||
|
||||
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] |
||||
|
||||
intermediates = {'x_inter': [img], 'pred_x0': [img]} |
||||
time_range = list(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 PLMS Sampling with {total_steps} timesteps") |
||||
|
||||
iterator = tqdm(time_range, desc='PLMS Sampler', total=total_steps) |
||||
old_eps = [] |
||||
|
||||
for i, step in enumerate(iterator): |
||||
index = total_steps - i - 1 |
||||
ts = torch.full((b,), step, device=device, dtype=torch.long) |
||||
ts_next = torch.full((b,), time_range[min(i + 1, len(time_range) - 1)], 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 |
||||
|
||||
outs = self.p_sample_plms(img, 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, |
||||
unconditional_conditioning=unconditional_conditioning, |
||||
old_eps=old_eps, t_next=ts_next, |
||||
dynamic_threshold=dynamic_threshold) |
||||
img, pred_x0, e_t = outs |
||||
old_eps.append(e_t) |
||||
if len(old_eps) >= 4: |
||||
old_eps.pop(0) |
||||
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_plms(self, x, 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., unconditional_conditioning=None, old_eps=None, t_next=None, |
||||
dynamic_threshold=None): |
||||
b, *_, device = *x.shape, x.device |
||||
|
||||
def get_model_output(x, t): |
||||
if unconditional_conditioning is None or unconditional_guidance_scale == 1.: |
||||
e_t = self.model.apply_model(x, t, c) |
||||
else: |
||||
x_in = torch.cat([x] * 2) |
||||
t_in = torch.cat([t] * 2) |
||||
c_in = torch.cat([unconditional_conditioning, c]) |
||||
e_t_uncond, e_t = self.model.apply_model(x_in, t_in, c_in).chunk(2) |
||||
e_t = e_t_uncond + unconditional_guidance_scale * (e_t - e_t_uncond) |
||||
|
||||
if score_corrector is not None: |
||||
assert self.model.parameterization == "eps" |
||||
e_t = score_corrector.modify_score(self.model, e_t, x, t, c, **corrector_kwargs) |
||||
|
||||
return e_t |
||||
|
||||
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 |
||||
|
||||
def get_x_prev_and_pred_x0(e_t, index): |
||||
# 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 |
||||
pred_x0 = (x - sqrt_one_minus_at * e_t) / a_t.sqrt() |
||||
if quantize_denoised: |
||||
pred_x0, _, *_ = self.model.first_stage_model.quantize(pred_x0) |
||||
if dynamic_threshold is not None: |
||||
pred_x0 = norm_thresholding(pred_x0, dynamic_threshold) |
||||
# 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 |
||||
|
||||
e_t = get_model_output(x, t) |
||||
if len(old_eps) == 0: |
||||
# Pseudo Improved Euler (2nd order) |
||||
x_prev, pred_x0 = get_x_prev_and_pred_x0(e_t, index) |
||||
e_t_next = get_model_output(x_prev, t_next) |
||||
e_t_prime = (e_t + e_t_next) / 2 |
||||
elif len(old_eps) == 1: |
||||
# 2nd order Pseudo Linear Multistep (Adams-Bashforth) |
||||
e_t_prime = (3 * e_t - old_eps[-1]) / 2 |
||||
elif len(old_eps) == 2: |
||||
# 3nd order Pseudo Linear Multistep (Adams-Bashforth) |
||||
e_t_prime = (23 * e_t - 16 * old_eps[-1] + 5 * old_eps[-2]) / 12 |
||||
elif len(old_eps) >= 3: |
||||
# 4nd order Pseudo Linear Multistep (Adams-Bashforth) |
||||
e_t_prime = (55 * e_t - 59 * old_eps[-1] + 37 * old_eps[-2] - 9 * old_eps[-3]) / 24 |
||||
|
||||
x_prev, pred_x0 = get_x_prev_and_pred_x0(e_t_prime, index) |
||||
|
||||
return x_prev, pred_x0, e_t |
@ -1,22 +0,0 @@
|
||||
import torch |
||||
import numpy as np |
||||
|
||||
|
||||
def append_dims(x, target_dims): |
||||
"""Appends dimensions to the end of a tensor until it has target_dims dimensions. |
||||
From https://github.com/crowsonkb/k-diffusion/blob/master/k_diffusion/utils.py""" |
||||
dims_to_append = target_dims - x.ndim |
||||
if dims_to_append < 0: |
||||
raise ValueError(f'input has {x.ndim} dims but target_dims is {target_dims}, which is less') |
||||
return x[(...,) + (None,) * dims_to_append] |
||||
|
||||
|
||||
def norm_thresholding(x0, value): |
||||
s = append_dims(x0.pow(2).flatten(1).mean(1).sqrt().clamp(min=value), x0.ndim) |
||||
return x0 * (value / s) |
||||
|
||||
|
||||
def spatial_norm_thresholding(x0, value): |
||||
# b c h w |
||||
s = x0.pow(2).mean(1, keepdim=True).sqrt().clamp(min=value) |
||||
return x0 * (value / s) |
Loading…
Reference in new issue