""" wild mixture of https://github.com/lucidrains/denoising-diffusion-pytorch/blob/7706bdfc6f527f58d33f84b7b522e61e6e3164b3/denoising_diffusion_pytorch/denoising_diffusion_pytorch.py https://github.com/openai/improved-diffusion/blob/e94489283bb876ac1477d5dd7709bbbd2d9902ce/improved_diffusion/gaussian_diffusion.py https://github.com/CompVis/taming-transformers -- merci """ import logging from functools import partial import numpy as np import pytorch_lightning as pl import torch import torch.nn as nn from einops import rearrange from torchvision.utils import make_grid from tqdm import tqdm from imaginairy.modules.diffusion.util import ( extract_into_tensor, make_beta_schedule, noise_like, ) from imaginairy.modules.distributions import DiagonalGaussianDistribution from imaginairy.utils import instantiate_from_config, log_params logger = logging.getLogger(__name__) __conditioning_keys__ = {"concat": "c_concat", "crossattn": "c_crossattn", "adm": "y"} def disabled_train(self, mode=True): """Overwrite model.train with this function to make sure train/eval mode does not change anymore.""" return self def uniform_on_device(r1, r2, shape, device): return (r1 - r2) * torch.rand(*shape, device=device) + r2 class DDPM(pl.LightningModule): """ classic DDPM with Gaussian diffusion, in image space Denoising diffusion probabilistic models """ def __init__( self, unet_config, timesteps=1000, beta_schedule="linear", loss_type="l2", ckpt_path=None, ignore_keys=[], load_only_unet=False, monitor="val/loss", first_stage_key="image", image_size=256, channels=3, log_every_t=100, clip_denoised=True, linear_start=1e-4, linear_end=2e-2, cosine_s=8e-3, given_betas=None, original_elbo_weight=0.0, v_posterior=0.0, # weight for choosing posterior variance as sigma = (1-v) * beta_tilde + v * beta l_simple_weight=1.0, conditioning_key=None, parameterization="eps", # all assuming fixed variance schedules scheduler_config=None, use_positional_encodings=False, learn_logvar=False, logvar_init=0.0, ): super().__init__() assert parameterization in [ "eps", "x0", ], 'currently only supporting "eps" and "x0"' self.parameterization = parameterization logger.debug( f"{self.__class__.__name__}: Running in {self.parameterization}-prediction mode" ) self.cond_stage_model = None self.clip_denoised = clip_denoised self.log_every_t = log_every_t self.first_stage_key = first_stage_key self.image_size = image_size # try conv? self.channels = channels self.use_positional_encodings = use_positional_encodings self.model = DiffusionWrapper(unet_config, conditioning_key) log_params(self.model) self.use_scheduler = scheduler_config is not None if self.use_scheduler: self.scheduler_config = scheduler_config self.v_posterior = v_posterior self.original_elbo_weight = original_elbo_weight self.l_simple_weight = l_simple_weight if monitor is not None: self.monitor = monitor if ckpt_path is not None: self.init_from_ckpt( ckpt_path, ignore_keys=ignore_keys, only_model=load_only_unet ) self.register_schedule( given_betas=given_betas, beta_schedule=beta_schedule, timesteps=timesteps, linear_start=linear_start, linear_end=linear_end, cosine_s=cosine_s, ) self.loss_type = loss_type self.learn_logvar = learn_logvar self.logvar = torch.full(fill_value=logvar_init, size=(self.num_timesteps,)) if self.learn_logvar: self.logvar = nn.Parameter(self.logvar, requires_grad=True) def register_schedule( self, given_betas=None, beta_schedule="linear", timesteps=1000, linear_start=1e-4, linear_end=2e-2, cosine_s=8e-3, ): 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 = 1.0 - betas alphas_cumprod = np.cumprod(alphas, axis=0) alphas_cumprod_prev = np.append(1.0, alphas_cumprod[:-1]) (timesteps,) = betas.shape self.num_timesteps = int(timesteps) self.linear_start = linear_start self.linear_end = linear_end assert ( alphas_cumprod.shape[0] == self.num_timesteps ), "alphas have to be defined for each timestep" to_torch = partial(torch.tensor, dtype=torch.float32) self.register_buffer("betas", to_torch(betas)) self.register_buffer("alphas_cumprod", to_torch(alphas_cumprod)) self.register_buffer("alphas_cumprod_prev", to_torch(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))) self.register_buffer( "sqrt_one_minus_alphas_cumprod", to_torch(np.sqrt(1.0 - alphas_cumprod)) ) self.register_buffer( "log_one_minus_alphas_cumprod", to_torch(np.log(1.0 - alphas_cumprod)) ) self.register_buffer( "sqrt_recip_alphas_cumprod", to_torch(np.sqrt(1.0 / alphas_cumprod)) ) self.register_buffer( "sqrt_recipm1_alphas_cumprod", to_torch(np.sqrt(1.0 / alphas_cumprod - 1)) ) # calculations for posterior q(x_{t-1} | x_t, x_0) posterior_variance = (1 - self.v_posterior) * betas * ( 1.0 - alphas_cumprod_prev ) / (1.0 - alphas_cumprod) + self.v_posterior * betas # above: equal to 1. / (1. / (1. - alpha_cumprod_tm1) + alpha_t / beta_t) self.register_buffer("posterior_variance", to_torch(posterior_variance)) # below: log calculation clipped because the posterior variance is 0 at the beginning of the diffusion chain self.register_buffer( "posterior_log_variance_clipped", to_torch(np.log(np.maximum(posterior_variance, 1e-20))), ) self.register_buffer( "posterior_mean_coef1", to_torch(betas * np.sqrt(alphas_cumprod_prev) / (1.0 - alphas_cumprod)), ) self.register_buffer( "posterior_mean_coef2", to_torch( (1.0 - alphas_cumprod_prev) * np.sqrt(alphas) / (1.0 - alphas_cumprod) ), ) if self.parameterization == "eps": lvlb_weights = self.betas**2 / ( 2 * self.posterior_variance * to_torch(alphas) * (1 - self.alphas_cumprod) ) elif self.parameterization == "x0": lvlb_weights = ( 0.5 * np.sqrt(torch.Tensor(alphas_cumprod)) / (2.0 * 1 - torch.Tensor(alphas_cumprod)) ) else: raise NotImplementedError("mu not supported") # TODO how to choose this term lvlb_weights[0] = lvlb_weights[1] self.register_buffer("lvlb_weights", lvlb_weights, persistent=False) assert not torch.isnan(self.lvlb_weights).all() class LatentDiffusion(DDPM): """main class""" def __init__( self, first_stage_config, cond_stage_config, num_timesteps_cond=None, cond_stage_key="image", cond_stage_trainable=False, concat_mode=True, cond_stage_forward=None, conditioning_key=None, scale_factor=1.0, scale_by_std=False, *args, **kwargs, ): self.num_timesteps_cond = ( 1 if num_timesteps_cond is None else num_timesteps_cond ) self.scale_by_std = scale_by_std assert self.num_timesteps_cond <= kwargs["timesteps"] # for backwards compatibility after implementation of DiffusionWrapper if conditioning_key is None: conditioning_key = "concat" if concat_mode else "crossattn" if cond_stage_config == "__is_unconditional__": conditioning_key = None ckpt_path = kwargs.pop("ckpt_path", None) ignore_keys = kwargs.pop("ignore_keys", []) super().__init__(conditioning_key=conditioning_key, *args, **kwargs) self.concat_mode = concat_mode self.cond_stage_trainable = cond_stage_trainable self.cond_stage_key = cond_stage_key try: self.num_downs = len(first_stage_config.params.ddconfig.ch_mult) - 1 except: # noqa logger.exception("Bad num downs?") self.num_downs = 0 if not scale_by_std: self.scale_factor = scale_factor else: self.register_buffer("scale_factor", torch.tensor(scale_factor)) self.instantiate_first_stage(first_stage_config) self.instantiate_cond_stage(cond_stage_config) self.cond_stage_forward = cond_stage_forward self.clip_denoised = False self.bbox_tokenizer = None self.restarted_from_ckpt = False if ckpt_path is not None: self.init_from_ckpt(ckpt_path, ignore_keys) self.restarted_from_ckpt = True def make_cond_schedule( self, ): self.cond_ids = torch.full( size=(self.num_timesteps,), fill_value=self.num_timesteps - 1, dtype=torch.long, ) ids = torch.round( torch.linspace(0, self.num_timesteps - 1, self.num_timesteps_cond) ).long() self.cond_ids[: self.num_timesteps_cond] = ids def register_schedule( self, given_betas=None, beta_schedule="linear", timesteps=1000, linear_start=1e-4, linear_end=2e-2, cosine_s=8e-3, ): super().register_schedule( given_betas, beta_schedule, timesteps, linear_start, linear_end, cosine_s ) self.shorten_cond_schedule = self.num_timesteps_cond > 1 if self.shorten_cond_schedule: self.make_cond_schedule() def instantiate_first_stage(self, config): model = instantiate_from_config(config) self.first_stage_model = model.eval() self.first_stage_model.train = disabled_train for param in self.first_stage_model.parameters(): param.requires_grad = False def instantiate_cond_stage(self, config): if not self.cond_stage_trainable: if config == "__is_first_stage__": logger.debug("Using first stage also as cond stage.") self.cond_stage_model = self.first_stage_model elif config == "__is_unconditional__": logger.debug( f"Training {self.__class__.__name__} as an unconditional model." ) self.cond_stage_model = None # self.be_unconditional = True else: model = instantiate_from_config(config) self.cond_stage_model = model.eval() self.cond_stage_model.train = disabled_train for param in self.cond_stage_model.parameters(): param.requires_grad = False else: assert config != "__is_first_stage__" assert config != "__is_unconditional__" model = instantiate_from_config(config) self.cond_stage_model = model def _get_denoise_row_from_list( self, samples, desc="", force_no_decoder_quantization=False ): denoise_row = [] for zd in tqdm(samples, desc=desc): denoise_row.append( self.decode_first_stage( zd.to(self.device), force_not_quantize=force_no_decoder_quantization ) ) n_imgs_per_row = len(denoise_row) denoise_row = torch.stack(denoise_row) # n_log_step, n_row, C, H, W denoise_grid = rearrange(denoise_row, "n b c h w -> b n c h w") denoise_grid = rearrange(denoise_grid, "b n c h w -> (b n) c h w") denoise_grid = make_grid(denoise_grid, nrow=n_imgs_per_row) return denoise_grid def get_first_stage_encoding(self, encoder_posterior): if isinstance(encoder_posterior, DiagonalGaussianDistribution): z = encoder_posterior.sample() elif isinstance(encoder_posterior, torch.Tensor): z = encoder_posterior else: raise NotImplementedError( f"encoder_posterior of type '{type(encoder_posterior)}' not yet implemented" ) return self.scale_factor * z def get_learned_conditioning(self, c): if self.cond_stage_forward is None: if hasattr(self.cond_stage_model, "encode") and callable( self.cond_stage_model.encode ): c = self.cond_stage_model.encode(c) if isinstance(c, DiagonalGaussianDistribution): c = c.mode() else: c = self.cond_stage_model(c) else: assert hasattr(self.cond_stage_model, self.cond_stage_forward) c = getattr(self.cond_stage_model, self.cond_stage_forward)(c) return c def meshgrid(self, h, w): y = torch.arange(0, h).view(h, 1, 1).repeat(1, w, 1) x = torch.arange(0, w).view(1, w, 1).repeat(h, 1, 1) arr = torch.cat([y, x], dim=-1) return arr def delta_border(self, h, w): """ :param h: height :param w: width :return: normalized distance to image border, wtith min distance = 0 at border and max dist = 0.5 at image center """ lower_right_corner = torch.tensor([h - 1, w - 1]).view(1, 1, 2) arr = self.meshgrid(h, w) / lower_right_corner dist_left_up = torch.min(arr, dim=-1, keepdims=True)[0] dist_right_down = torch.min(1 - arr, dim=-1, keepdims=True)[0] edge_dist = torch.min( torch.cat([dist_left_up, dist_right_down], dim=-1), dim=-1 )[0] return edge_dist def get_weighting(self, h, w, Ly, Lx, device): weighting = self.delta_border(h, w) weighting = torch.clip( weighting, self.split_input_params["clip_min_weight"], self.split_input_params["clip_max_weight"], ) weighting = weighting.view(1, h * w, 1).repeat(1, 1, Ly * Lx).to(device) if self.split_input_params["tie_braker"]: L_weighting = self.delta_border(Ly, Lx) L_weighting = torch.clip( L_weighting, self.split_input_params["clip_min_tie_weight"], self.split_input_params["clip_max_tie_weight"], ) L_weighting = L_weighting.view(1, 1, Ly * Lx).to(device) weighting = weighting * L_weighting return weighting def get_fold_unfold( self, x, kernel_size, stride, uf=1, df=1 ): # todo load once not every time, shorten code """ :param x: img of size (bs, c, h, w) :return: n img crops of size (n, bs, c, kernel_size[0], kernel_size[1]) """ bs, nc, h, w = x.shape # number of crops in image Ly = (h - kernel_size[0]) // stride[0] + 1 Lx = (w - kernel_size[1]) // stride[1] + 1 if uf == 1 and df == 1: fold_params = dict( kernel_size=kernel_size, dilation=1, padding=0, stride=stride ) unfold = torch.nn.Unfold(**fold_params) fold = torch.nn.Fold(output_size=x.shape[2:], **fold_params) weighting = self.get_weighting( kernel_size[0], kernel_size[1], Ly, Lx, x.device ).to(x.dtype) normalization = fold(weighting).view(1, 1, h, w) # normalizes the overlap weighting = weighting.view((1, 1, kernel_size[0], kernel_size[1], Ly * Lx)) elif uf > 1 and df == 1: fold_params = dict( kernel_size=kernel_size, dilation=1, padding=0, stride=stride ) unfold = torch.nn.Unfold(**fold_params) fold_params2 = dict( kernel_size=(kernel_size[0] * uf, kernel_size[0] * uf), dilation=1, padding=0, stride=(stride[0] * uf, stride[1] * uf), ) fold = torch.nn.Fold( output_size=(x.shape[2] * uf, x.shape[3] * uf), **fold_params2 ) weighting = self.get_weighting( kernel_size[0] * uf, kernel_size[1] * uf, Ly, Lx, x.device ).to(x.dtype) normalization = fold(weighting).view( 1, 1, h * uf, w * uf ) # normalizes the overlap weighting = weighting.view( (1, 1, kernel_size[0] * uf, kernel_size[1] * uf, Ly * Lx) ) elif df > 1 and uf == 1: fold_params = dict( kernel_size=kernel_size, dilation=1, padding=0, stride=stride ) unfold = torch.nn.Unfold(**fold_params) fold_params2 = dict( kernel_size=(kernel_size[0] // df, kernel_size[0] // df), dilation=1, padding=0, stride=(stride[0] // df, stride[1] // df), ) fold = torch.nn.Fold( output_size=(x.shape[2] // df, x.shape[3] // df), **fold_params2 ) weighting = self.get_weighting( kernel_size[0] // df, kernel_size[1] // df, Ly, Lx, x.device ).to(x.dtype) normalization = fold(weighting).view( 1, 1, h // df, w // df ) # normalizes the overlap weighting = weighting.view( (1, 1, kernel_size[0] // df, kernel_size[1] // df, Ly * Lx) ) else: raise NotImplementedError return fold, unfold, normalization, weighting @torch.no_grad() def get_input( self, batch, k, return_first_stage_outputs=False, force_c_encode=False, cond_key=None, return_original_cond=False, bs=None, ): x = super().get_input(batch, k) if bs is not None: x = x[:bs] x = x.to(self.device) encoder_posterior = self.encode_first_stage(x) z = self.get_first_stage_encoding(encoder_posterior).detach() if self.model.conditioning_key is not None: if cond_key is None: cond_key = self.cond_stage_key if cond_key != self.first_stage_key: if cond_key in ["caption", "coordinates_bbox"]: xc = batch[cond_key] elif cond_key == "class_label": xc = batch else: xc = super().get_input(batch, cond_key).to(self.device) else: xc = x if not self.cond_stage_trainable or force_c_encode: if isinstance(xc, dict) or isinstance(xc, list): # import pudb; pudb.set_trace() c = self.get_learned_conditioning(xc) else: c = self.get_learned_conditioning(xc.to(self.device)) else: c = xc if bs is not None: c = c[:bs] if self.use_positional_encodings: pos_x, pos_y = self.compute_latent_shifts(batch) ckey = __conditioning_keys__[self.model.conditioning_key] c = {ckey: c, "pos_x": pos_x, "pos_y": pos_y} else: c = None xc = None if self.use_positional_encodings: pos_x, pos_y = self.compute_latent_shifts(batch) c = {"pos_x": pos_x, "pos_y": pos_y} out = [z, c] if return_first_stage_outputs: xrec = self.decode_first_stage(z) out.extend([x, xrec]) if return_original_cond: out.append(xc) return out @torch.no_grad() def decode_first_stage(self, z, predict_cids=False, force_not_quantize=False): if predict_cids: if z.dim() == 4: z = torch.argmax(z.exp(), dim=1).long() z = self.first_stage_model.quantize.get_codebook_entry(z, shape=None) z = rearrange(z, "b h w c -> b c h w").contiguous() z = 1.0 / self.scale_factor * z return self.first_stage_model.decode(z) @torch.no_grad() def encode_first_stage(self, x): if ( hasattr(self, "split_input_params") and self.split_input_params["patch_distributed_vq"] ): ks = self.split_input_params["ks"] # eg. (128, 128) stride = self.split_input_params["stride"] # eg. (64, 64) df = self.split_input_params["vqf"] self.split_input_params["original_image_size"] = x.shape[-2:] bs, nc, h, w = x.shape if ks[0] > h or ks[1] > w: ks = (min(ks[0], h), min(ks[1], w)) logger.info("reducing Kernel") if stride[0] > h or stride[1] > w: stride = (min(stride[0], h), min(stride[1], w)) logger.info("reducing stride") fold, unfold, normalization, weighting = self.get_fold_unfold( x, ks, stride, df=df ) z = unfold(x) # (bn, nc * prod(**ks), L) # Reshape to img shape z = z.view( (z.shape[0], -1, ks[0], ks[1], z.shape[-1]) ) # (bn, nc, ks[0], ks[1], L ) output_list = [ self.first_stage_model.encode(z[:, :, :, :, i]) for i in range(z.shape[-1]) ] o = torch.stack(output_list, axis=-1) o = o * weighting # Reverse reshape to img shape o = o.view((o.shape[0], -1, o.shape[-1])) # (bn, nc * ks[0] * ks[1], L) # stitch crops together decoded = fold(o) decoded = decoded / normalization return decoded return self.first_stage_model.encode(x) def apply_model(self, x_noisy, t, cond, return_ids=False): if isinstance(cond, dict): # hybrid case, cond is exptected to be a dict pass else: if not isinstance(cond, list): cond = [cond] key = ( "c_concat" if self.model.conditioning_key == "concat" else "c_crossattn" ) cond = {key: cond} if hasattr(self, "split_input_params"): assert len(cond) == 1 # todo can only deal with one conditioning atm assert not return_ids ks = self.split_input_params["ks"] # eg. (128, 128) stride = self.split_input_params["stride"] # eg. (64, 64) h, w = x_noisy.shape[-2:] # noqa fold, unfold, normalization, weighting = self.get_fold_unfold( x_noisy, ks, stride ) z = unfold(x_noisy) # (bn, nc * prod(**ks), L) # Reshape to img shape z = z.view( (z.shape[0], -1, ks[0], ks[1], z.shape[-1]) ) # (bn, nc, ks[0], ks[1], L ) z_list = [z[:, :, :, :, i] for i in range(z.shape[-1])] if ( self.cond_stage_key in ["image", "LR_image", "segmentation", "bbox_img"] and self.model.conditioning_key ): # todo check for completeness c_key = next(iter(cond.keys())) # get key c = next(iter(cond.values())) # get value assert len(c) == 1 # todo extend to list with more than one elem c = c[0] # get element c = unfold(c) c = c.view( (c.shape[0], -1, ks[0], ks[1], c.shape[-1]) ) # (bn, nc, ks[0], ks[1], L ) cond_list = [{c_key: [c[:, :, :, :, i]]} for i in range(c.shape[-1])] elif self.cond_stage_key == "coordinates_bbox": assert ( "original_image_size" in self.split_input_params ), "BoudingBoxRescaling is missing original_image_size" # assuming padding of unfold is always 0 and its dilation is always 1 n_patches_per_row = int((w - ks[0]) / stride[0] + 1) full_img_h, full_img_w = self.split_input_params["original_image_size"] # as we are operating on latents, we need the factor from the original image size to the # spatial latent size to properly rescale the crops for regenerating the bbox annotations num_downs = self.first_stage_model.encoder.num_resolutions - 1 rescale_latent = 2 ** (num_downs) # get top left postions of patches as conforming for the bbbox tokenizer, therefore we # need to rescale the tl patch coordinates to be in between (0,1) tl_patch_coordinates = [ ( rescale_latent * stride[0] * (patch_nr % n_patches_per_row) / full_img_w, rescale_latent * stride[1] * (patch_nr // n_patches_per_row) / full_img_h, ) for patch_nr in range(z.shape[-1]) ] # patch_limits are tl_coord, width and height coordinates as (x_tl, y_tl, h, w) patch_limits = [ ( x_tl, y_tl, rescale_latent * ks[0] / full_img_w, rescale_latent * ks[1] / full_img_h, ) for x_tl, y_tl in tl_patch_coordinates ] # patch_values = [(np.arange(x_tl,min(x_tl+ks, 1.)),np.arange(y_tl,min(y_tl+ks, 1.))) for x_tl, y_tl in tl_patch_coordinates] # tokenize crop coordinates for the bounding boxes of the respective patches patch_limits_tknzd = [ torch.LongTensor(self.bbox_tokenizer._crop_encoder(bbox))[ # noqa None ].to( # noqa self.device ) for bbox in patch_limits ] # list of length l with tensors of shape (1, 2) # cut tknzd crop position from conditioning assert isinstance(cond, dict), "cond must be dict to be fed into model" cut_cond = cond["c_crossattn"][0][..., :-2].to(self.device) adapted_cond = torch.stack( [torch.cat([cut_cond, p], dim=1) for p in patch_limits_tknzd] ) adapted_cond = rearrange(adapted_cond, "l b n -> (l b) n") adapted_cond = self.get_learned_conditioning(adapted_cond) adapted_cond = rearrange( adapted_cond, "(l b) n d -> l b n d", l=z.shape[-1] ) cond_list = [{"c_crossattn": [e]} for e in adapted_cond] else: cond_list = [ cond for i in range(z.shape[-1]) ] # Todo make this more efficient # apply model by loop over crops output_list = [ self.model(z_list[i], t, **cond_list[i]) for i in range(z.shape[-1]) ] assert not isinstance( output_list[0], tuple ) # todo cant deal with multiple model outputs check this never happens o = torch.stack(output_list, axis=-1) o = o * weighting # Reverse reshape to img shape o = o.view((o.shape[0], -1, o.shape[-1])) # (bn, nc * ks[0] * ks[1], L) # stitch crops together x_recon = fold(o) / normalization else: x_recon = self.model(x_noisy, t, **cond) if isinstance(x_recon, tuple) and not return_ids: return x_recon[0] return x_recon def p_mean_variance( self, x, c, t, clip_denoised: bool, return_codebook_ids=False, quantize_denoised=False, return_x0=False, score_corrector=None, corrector_kwargs=None, ): t_in = t model_out = self.apply_model(x, t_in, c, return_ids=return_codebook_ids) if score_corrector is not None: assert self.parameterization == "eps" model_out = score_corrector.modify_score( self, model_out, x, t, c, **corrector_kwargs ) if return_codebook_ids: model_out, logits = model_out if self.parameterization == "eps": x_recon = self.predict_start_from_noise(x, t=t, noise=model_out) elif self.parameterization == "x0": x_recon = model_out else: raise NotImplementedError() if clip_denoised: x_recon.clamp_(-1.0, 1.0) if quantize_denoised: x_recon, _, _ = self.first_stage_model.quantize(x_recon) model_mean, posterior_variance, posterior_log_variance = self.q_posterior( x_start=x_recon, x_t=x, t=t ) if return_codebook_ids: return model_mean, posterior_variance, posterior_log_variance, logits if return_x0: return model_mean, posterior_variance, posterior_log_variance, x_recon return model_mean, posterior_variance, posterior_log_variance @torch.no_grad() def p_sample( self, x, c, t, clip_denoised=False, repeat_noise=False, return_codebook_ids=False, quantize_denoised=False, return_x0=False, temperature=1.0, noise_dropout=0.0, score_corrector=None, corrector_kwargs=None, ): b, *_, device = *x.shape, x.device outputs = self.p_mean_variance( x=x, c=c, t=t, clip_denoised=clip_denoised, return_codebook_ids=return_codebook_ids, quantize_denoised=quantize_denoised, return_x0=return_x0, score_corrector=score_corrector, corrector_kwargs=corrector_kwargs, ) if return_x0: model_mean, _, model_log_variance, x0 = outputs else: model_mean, _, model_log_variance = outputs noise = noise_like(x.shape, device, repeat_noise) * temperature if noise_dropout > 0.0: noise = torch.nn.functional.dropout(noise, p=noise_dropout) # no noise when t == 0 nonzero_mask = (1 - (t == 0).float()).reshape(b, *((1,) * (len(x.shape) - 1))) if return_x0: return ( model_mean + nonzero_mask * (0.5 * model_log_variance).exp() * noise, x0, ) return model_mean + nonzero_mask * (0.5 * model_log_variance).exp() * noise def q_sample(self, x_start, t, noise=None): noise = ( noise if noise is not None else torch.randn_like(x_start, device="cpu").to(x_start.device) ) return ( extract_into_tensor(self.sqrt_alphas_cumprod, t, x_start.shape) * x_start + extract_into_tensor(self.sqrt_one_minus_alphas_cumprod, t, x_start.shape) * noise ) class DiffusionWrapper(pl.LightningModule): def __init__(self, diff_model_config, conditioning_key): super().__init__() self.diffusion_model = instantiate_from_config(diff_model_config) self.conditioning_key = conditioning_key assert self.conditioning_key in [None, "concat", "crossattn", "hybrid", "adm"] def forward(self, x, t, c_concat: list = None, c_crossattn: list = None): if self.conditioning_key is None: out = self.diffusion_model(x, t) elif self.conditioning_key == "concat": xc = torch.cat([x] + c_concat, dim=1) out = self.diffusion_model(xc, t) elif self.conditioning_key == "crossattn": cc = torch.cat(c_crossattn, 1) out = self.diffusion_model(x, t, context=cc) elif self.conditioning_key == "hybrid": xc = torch.cat([x] + c_concat, dim=1) cc = torch.cat(c_crossattn, 1) out = self.diffusion_model(xc, t, context=cc) elif self.conditioning_key == "adm": cc = c_crossattn[0] out = self.diffusion_model(x, t, y=cc) else: raise NotImplementedError() return out