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Running
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Zero
| import torch | |
| from comfy.ldm.modules.diffusionmodules.util import make_beta_schedule | |
| import math | |
| def rescale_zero_terminal_snr_sigmas(sigmas): | |
| alphas_cumprod = 1 / ((sigmas * sigmas) + 1) | |
| alphas_bar_sqrt = alphas_cumprod.sqrt() | |
| # Store old values. | |
| alphas_bar_sqrt_0 = alphas_bar_sqrt[0].clone() | |
| alphas_bar_sqrt_T = alphas_bar_sqrt[-1].clone() | |
| # Shift so the last timestep is zero. | |
| alphas_bar_sqrt -= (alphas_bar_sqrt_T) | |
| # Scale so the first timestep is back to the old value. | |
| alphas_bar_sqrt *= alphas_bar_sqrt_0 / (alphas_bar_sqrt_0 - alphas_bar_sqrt_T) | |
| # Convert alphas_bar_sqrt to betas | |
| alphas_bar = alphas_bar_sqrt**2 # Revert sqrt | |
| alphas_bar[-1] = 4.8973451890853435e-08 | |
| return ((1 - alphas_bar) / alphas_bar) ** 0.5 | |
| class EPS: | |
| def calculate_input(self, sigma, noise): | |
| sigma = sigma.view(sigma.shape[:1] + (1,) * (noise.ndim - 1)) | |
| return noise / (sigma ** 2 + self.sigma_data ** 2) ** 0.5 | |
| def calculate_denoised(self, sigma, model_output, model_input): | |
| sigma = sigma.view(sigma.shape[:1] + (1,) * (model_output.ndim - 1)) | |
| return model_input - model_output * sigma | |
| def noise_scaling(self, sigma, noise, latent_image, max_denoise=False): | |
| if max_denoise: | |
| noise = noise * torch.sqrt(1.0 + sigma ** 2.0) | |
| else: | |
| noise = noise * sigma | |
| noise += latent_image | |
| return noise | |
| def inverse_noise_scaling(self, sigma, latent): | |
| return latent | |
| class V_PREDICTION(EPS): | |
| def calculate_denoised(self, sigma, model_output, model_input): | |
| sigma = sigma.view(sigma.shape[:1] + (1,) * (model_output.ndim - 1)) | |
| return model_input * self.sigma_data ** 2 / (sigma ** 2 + self.sigma_data ** 2) - model_output * sigma * self.sigma_data / (sigma ** 2 + self.sigma_data ** 2) ** 0.5 | |
| class EDM(V_PREDICTION): | |
| def calculate_denoised(self, sigma, model_output, model_input): | |
| sigma = sigma.view(sigma.shape[:1] + (1,) * (model_output.ndim - 1)) | |
| return model_input * self.sigma_data ** 2 / (sigma ** 2 + self.sigma_data ** 2) + model_output * sigma * self.sigma_data / (sigma ** 2 + self.sigma_data ** 2) ** 0.5 | |
| class CONST: | |
| def calculate_input(self, sigma, noise): | |
| return noise | |
| def calculate_denoised(self, sigma, model_output, model_input): | |
| sigma = sigma.view(sigma.shape[:1] + (1,) * (model_output.ndim - 1)) | |
| return model_input - model_output * sigma | |
| def noise_scaling(self, sigma, noise, latent_image, max_denoise=False): | |
| return sigma * noise + (1.0 - sigma) * latent_image | |
| def inverse_noise_scaling(self, sigma, latent): | |
| return latent / (1.0 - sigma) | |
| class ModelSamplingDiscrete(torch.nn.Module): | |
| def __init__(self, model_config=None, zsnr=None): | |
| super().__init__() | |
| if model_config is not None: | |
| sampling_settings = model_config.sampling_settings | |
| else: | |
| sampling_settings = {} | |
| beta_schedule = sampling_settings.get("beta_schedule", "linear") | |
| linear_start = sampling_settings.get("linear_start", 0.00085) | |
| linear_end = sampling_settings.get("linear_end", 0.012) | |
| timesteps = sampling_settings.get("timesteps", 1000) | |
| if zsnr is None: | |
| zsnr = sampling_settings.get("zsnr", False) | |
| self._register_schedule(given_betas=None, beta_schedule=beta_schedule, timesteps=timesteps, linear_start=linear_start, linear_end=linear_end, cosine_s=8e-3, zsnr=zsnr) | |
| self.sigma_data = 1.0 | |
| def _register_schedule(self, given_betas=None, beta_schedule="linear", timesteps=1000, | |
| linear_start=1e-4, linear_end=2e-2, cosine_s=8e-3, zsnr=False): | |
| if given_betas is not None: | |
| betas = given_betas | |
| else: | |
| betas = make_beta_schedule(beta_schedule, timesteps, linear_start=linear_start, linear_end=linear_end, cosine_s=cosine_s) | |
| alphas = 1. - betas | |
| alphas_cumprod = torch.cumprod(alphas, dim=0) | |
| timesteps, = betas.shape | |
| self.num_timesteps = int(timesteps) | |
| self.linear_start = linear_start | |
| self.linear_end = linear_end | |
| # self.register_buffer('betas', torch.tensor(betas, dtype=torch.float32)) | |
| # self.register_buffer('alphas_cumprod', torch.tensor(alphas_cumprod, dtype=torch.float32)) | |
| # self.register_buffer('alphas_cumprod_prev', torch.tensor(alphas_cumprod_prev, dtype=torch.float32)) | |
| sigmas = ((1 - alphas_cumprod) / alphas_cumprod) ** 0.5 | |
| if zsnr: | |
| sigmas = rescale_zero_terminal_snr_sigmas(sigmas) | |
| self.set_sigmas(sigmas) | |
| def set_sigmas(self, sigmas): | |
| self.register_buffer('sigmas', sigmas.float()) | |
| self.register_buffer('log_sigmas', sigmas.log().float()) | |
| def sigma_min(self): | |
| return self.sigmas[0] | |
| def sigma_max(self): | |
| return self.sigmas[-1] | |
| def timestep(self, sigma): | |
| log_sigma = sigma.log() | |
| dists = log_sigma.to(self.log_sigmas.device) - self.log_sigmas[:, None] | |
| return dists.abs().argmin(dim=0).view(sigma.shape).to(sigma.device) | |
| def sigma(self, timestep): | |
| t = torch.clamp(timestep.float().to(self.log_sigmas.device), min=0, max=(len(self.sigmas) - 1)) | |
| low_idx = t.floor().long() | |
| high_idx = t.ceil().long() | |
| w = t.frac() | |
| log_sigma = (1 - w) * self.log_sigmas[low_idx] + w * self.log_sigmas[high_idx] | |
| return log_sigma.exp().to(timestep.device) | |
| def percent_to_sigma(self, percent): | |
| if percent <= 0.0: | |
| return 999999999.9 | |
| if percent >= 1.0: | |
| return 0.0 | |
| percent = 1.0 - percent | |
| return self.sigma(torch.tensor(percent * 999.0)).item() | |
| class ModelSamplingDiscreteEDM(ModelSamplingDiscrete): | |
| def timestep(self, sigma): | |
| return 0.25 * sigma.log() | |
| def sigma(self, timestep): | |
| return (timestep / 0.25).exp() | |
| class ModelSamplingContinuousEDM(torch.nn.Module): | |
| def __init__(self, model_config=None): | |
| super().__init__() | |
| if model_config is not None: | |
| sampling_settings = model_config.sampling_settings | |
| else: | |
| sampling_settings = {} | |
| sigma_min = sampling_settings.get("sigma_min", 0.002) | |
| sigma_max = sampling_settings.get("sigma_max", 120.0) | |
| sigma_data = sampling_settings.get("sigma_data", 1.0) | |
| self.set_parameters(sigma_min, sigma_max, sigma_data) | |
| def set_parameters(self, sigma_min, sigma_max, sigma_data): | |
| self.sigma_data = sigma_data | |
| sigmas = torch.linspace(math.log(sigma_min), math.log(sigma_max), 1000).exp() | |
| self.register_buffer('sigmas', sigmas) #for compatibility with some schedulers | |
| self.register_buffer('log_sigmas', sigmas.log()) | |
| def sigma_min(self): | |
| return self.sigmas[0] | |
| def sigma_max(self): | |
| return self.sigmas[-1] | |
| def timestep(self, sigma): | |
| return 0.25 * sigma.log() | |
| def sigma(self, timestep): | |
| return (timestep / 0.25).exp() | |
| def percent_to_sigma(self, percent): | |
| if percent <= 0.0: | |
| return 999999999.9 | |
| if percent >= 1.0: | |
| return 0.0 | |
| percent = 1.0 - percent | |
| log_sigma_min = math.log(self.sigma_min) | |
| return math.exp((math.log(self.sigma_max) - log_sigma_min) * percent + log_sigma_min) | |
| class ModelSamplingContinuousV(ModelSamplingContinuousEDM): | |
| def timestep(self, sigma): | |
| return sigma.atan() / math.pi * 2 | |
| def sigma(self, timestep): | |
| return (timestep * math.pi / 2).tan() | |
| def time_snr_shift(alpha, t): | |
| if alpha == 1.0: | |
| return t | |
| return alpha * t / (1 + (alpha - 1) * t) | |
| class ModelSamplingDiscreteFlow(torch.nn.Module): | |
| def __init__(self, model_config=None): | |
| super().__init__() | |
| if model_config is not None: | |
| sampling_settings = model_config.sampling_settings | |
| else: | |
| sampling_settings = {} | |
| self.set_parameters(shift=sampling_settings.get("shift", 1.0), multiplier=sampling_settings.get("multiplier", 1000)) | |
| def set_parameters(self, shift=1.0, timesteps=1000, multiplier=1000): | |
| self.shift = shift | |
| self.multiplier = multiplier | |
| ts = self.sigma((torch.arange(1, timesteps + 1, 1) / timesteps) * multiplier) | |
| self.register_buffer('sigmas', ts) | |
| def sigma_min(self): | |
| return self.sigmas[0] | |
| def sigma_max(self): | |
| return self.sigmas[-1] | |
| def timestep(self, sigma): | |
| return sigma * self.multiplier | |
| def sigma(self, timestep): | |
| return time_snr_shift(self.shift, timestep / self.multiplier) | |
| def percent_to_sigma(self, percent): | |
| if percent <= 0.0: | |
| return 1.0 | |
| if percent >= 1.0: | |
| return 0.0 | |
| return 1.0 - percent | |
| class StableCascadeSampling(ModelSamplingDiscrete): | |
| def __init__(self, model_config=None): | |
| super().__init__() | |
| if model_config is not None: | |
| sampling_settings = model_config.sampling_settings | |
| else: | |
| sampling_settings = {} | |
| self.set_parameters(sampling_settings.get("shift", 1.0)) | |
| def set_parameters(self, shift=1.0, cosine_s=8e-3): | |
| self.shift = shift | |
| self.cosine_s = torch.tensor(cosine_s) | |
| self._init_alpha_cumprod = torch.cos(self.cosine_s / (1 + self.cosine_s) * torch.pi * 0.5) ** 2 | |
| #This part is just for compatibility with some schedulers in the codebase | |
| self.num_timesteps = 10000 | |
| sigmas = torch.empty((self.num_timesteps), dtype=torch.float32) | |
| for x in range(self.num_timesteps): | |
| t = (x + 1) / self.num_timesteps | |
| sigmas[x] = self.sigma(t) | |
| self.set_sigmas(sigmas) | |
| def sigma(self, timestep): | |
| alpha_cumprod = (torch.cos((timestep + self.cosine_s) / (1 + self.cosine_s) * torch.pi * 0.5) ** 2 / self._init_alpha_cumprod) | |
| if self.shift != 1.0: | |
| var = alpha_cumprod | |
| logSNR = (var/(1-var)).log() | |
| logSNR += 2 * torch.log(1.0 / torch.tensor(self.shift)) | |
| alpha_cumprod = logSNR.sigmoid() | |
| alpha_cumprod = alpha_cumprod.clamp(0.0001, 0.9999) | |
| return ((1 - alpha_cumprod) / alpha_cumprod) ** 0.5 | |
| def timestep(self, sigma): | |
| var = 1 / ((sigma * sigma) + 1) | |
| var = var.clamp(0, 1.0) | |
| s, min_var = self.cosine_s.to(var.device), self._init_alpha_cumprod.to(var.device) | |
| t = (((var * min_var) ** 0.5).acos() / (torch.pi * 0.5)) * (1 + s) - s | |
| return t | |
| def percent_to_sigma(self, percent): | |
| if percent <= 0.0: | |
| return 999999999.9 | |
| if percent >= 1.0: | |
| return 0.0 | |
| percent = 1.0 - percent | |
| return self.sigma(torch.tensor(percent)) | |
| def flux_time_shift(mu: float, sigma: float, t): | |
| return math.exp(mu) / (math.exp(mu) + (1 / t - 1) ** sigma) | |
| class ModelSamplingFlux(torch.nn.Module): | |
| def __init__(self, model_config=None): | |
| super().__init__() | |
| if model_config is not None: | |
| sampling_settings = model_config.sampling_settings | |
| else: | |
| sampling_settings = {} | |
| self.set_parameters(shift=sampling_settings.get("shift", 1.15)) | |
| def set_parameters(self, shift=1.15, timesteps=10000): | |
| self.shift = shift | |
| ts = self.sigma((torch.arange(1, timesteps + 1, 1) / timesteps)) | |
| self.register_buffer('sigmas', ts) | |
| def sigma_min(self): | |
| return self.sigmas[0] | |
| def sigma_max(self): | |
| return self.sigmas[-1] | |
| def timestep(self, sigma): | |
| return sigma | |
| def sigma(self, timestep): | |
| return flux_time_shift(self.shift, 1.0, timestep) | |
| def percent_to_sigma(self, percent): | |
| if percent <= 0.0: | |
| return 1.0 | |
| if percent >= 1.0: | |
| return 0.0 | |
| return 1.0 - percent | |