import math from contextlib import contextmanager from typing import Any, Dict, List, Optional, Tuple, Union import pytorch_lightning as pl import torch from omegaconf import ListConfig, OmegaConf from safetensors.torch import load_file as load_safetensors from torch.optim.lr_scheduler import LambdaLR from ..modules import UNCONDITIONAL_CONFIG from ..modules.autoencoding.temporal_ae import VideoDecoder from ..modules.diffusionmodules.wrappers import OPENAIUNETWRAPPER from ..modules.ema import LitEma from ..util import ( default, disabled_train, get_obj_from_str, instantiate_from_config, log_txt_as_img, ) class DiffusionEngine(pl.LightningModule): def __init__( self, network_config, denoiser_config, first_stage_config, conditioner_config: Union[None, Dict, ListConfig, OmegaConf] = None, sampler_config: Union[None, Dict, ListConfig, OmegaConf] = None, optimizer_config: Union[None, Dict, ListConfig, OmegaConf] = None, scheduler_config: Union[None, Dict, ListConfig, OmegaConf] = None, loss_fn_config: Union[None, Dict, ListConfig, OmegaConf] = None, network_wrapper: Union[None, str] = None, ckpt_path: Union[None, str] = None, use_ema: bool = False, ema_decay_rate: float = 0.9999, scale_factor: float = 1.0, disable_first_stage_autocast=False, input_key: str = "jpg", log_keys: Union[List, None] = None, no_cond_log: bool = False, compile_model: bool = False, en_and_decode_n_samples_a_time: Optional[int] = None, ): super().__init__() self.log_keys = log_keys self.input_key = input_key self.optimizer_config = default( optimizer_config, {"target": "torch.optim.AdamW"} ) model = instantiate_from_config(network_config) self.model = get_obj_from_str(default(network_wrapper, OPENAIUNETWRAPPER))( model, compile_model=compile_model ) self.denoiser = instantiate_from_config(denoiser_config) self.sampler = ( instantiate_from_config(sampler_config) if sampler_config is not None else None ) self.conditioner = instantiate_from_config( default(conditioner_config, UNCONDITIONAL_CONFIG) ) self.scheduler_config = scheduler_config self._init_first_stage(first_stage_config) self.loss_fn = ( instantiate_from_config(loss_fn_config) if loss_fn_config is not None else None ) self.use_ema = use_ema if self.use_ema: self.model_ema = LitEma(self.model, decay=ema_decay_rate) print(f"Keeping EMAs of {len(list(self.model_ema.buffers()))}.") self.scale_factor = scale_factor self.disable_first_stage_autocast = disable_first_stage_autocast self.no_cond_log = no_cond_log if ckpt_path is not None: self.init_from_ckpt(ckpt_path) self.en_and_decode_n_samples_a_time = en_and_decode_n_samples_a_time def init_from_ckpt( self, path: str, ) -> None: if path.endswith("ckpt"): sd = torch.load(path, map_location="cpu")["state_dict"] elif path.endswith("safetensors"): sd = load_safetensors(path) else: raise NotImplementedError missing, unexpected = self.load_state_dict(sd, strict=False) print( f"Restored from {path} with {len(missing)} missing and {len(unexpected)} unexpected keys" ) if len(missing) > 0: print(f"Missing Keys: {missing}") if len(unexpected) > 0: print(f"Unexpected Keys: {unexpected}") def _init_first_stage(self, config): model = instantiate_from_config(config).eval() model.train = disabled_train for param in model.parameters(): param.requires_grad = False self.first_stage_model = model def get_input(self, batch): # assuming unified data format, dataloader returns a dict. # image tensors should be scaled to -1 ... 1 and in bchw format return batch[self.input_key] @torch.no_grad() def decode_first_stage(self, z): z = 1.0 / self.scale_factor * z n_samples = default(self.en_and_decode_n_samples_a_time, z.shape[0]) n_rounds = math.ceil(z.shape[0] / n_samples) all_out = [] with torch.autocast("cuda", enabled=not self.disable_first_stage_autocast): for n in range(n_rounds): if isinstance(self.first_stage_model.decoder, VideoDecoder): kwargs = {"timesteps": len(z[n * n_samples : (n + 1) * n_samples])} else: kwargs = {} out = self.first_stage_model.decode( z[n * n_samples : (n + 1) * n_samples], **kwargs ) all_out.append(out) out = torch.cat(all_out, dim=0) return out @torch.no_grad() def encode_first_stage(self, x): n_samples = default(self.en_and_decode_n_samples_a_time, x.shape[0]) n_rounds = math.ceil(x.shape[0] / n_samples) all_out = [] with torch.autocast("cuda", enabled=not self.disable_first_stage_autocast): for n in range(n_rounds): out = self.first_stage_model.encode( x[n * n_samples : (n + 1) * n_samples] ) all_out.append(out) z = torch.cat(all_out, dim=0) z = self.scale_factor * z return z def forward(self, x, batch): loss = self.loss_fn(self.model, self.denoiser, self.conditioner, x, batch) loss_mean = loss.mean() loss_dict = {"loss": loss_mean} return loss_mean, loss_dict def shared_step(self, batch: Dict) -> Any: x = self.get_input(batch) x = self.encode_first_stage(x) batch["global_step"] = self.global_step loss, loss_dict = self(x, batch) return loss, loss_dict def training_step(self, batch, batch_idx): loss, loss_dict = self.shared_step(batch) self.log_dict( loss_dict, prog_bar=True, logger=True, on_step=True, on_epoch=False ) self.log( "global_step", self.global_step, prog_bar=True, logger=True, on_step=True, on_epoch=False, ) if self.scheduler_config is not None: lr = self.optimizers().param_groups[0]["lr"] self.log( "lr_abs", lr, prog_bar=True, logger=True, on_step=True, on_epoch=False ) return loss def on_train_start(self, *args, **kwargs): if self.sampler is None or self.loss_fn is None: raise ValueError("Sampler and loss function need to be set for training.") def on_train_batch_end(self, *args, **kwargs): if self.use_ema: self.model_ema(self.model) @contextmanager def ema_scope(self, context=None): if self.use_ema: self.model_ema.store(self.model.parameters()) self.model_ema.copy_to(self.model) if context is not None: print(f"{context}: Switched to EMA weights") try: yield None finally: if self.use_ema: self.model_ema.restore(self.model.parameters()) if context is not None: print(f"{context}: Restored training weights") def instantiate_optimizer_from_config(self, params, lr, cfg): return get_obj_from_str(cfg["target"])( params, lr=lr, **cfg.get("params", dict()) ) def configure_optimizers(self): lr = self.learning_rate params = list(self.model.parameters()) for embedder in self.conditioner.embedders: if embedder.is_trainable: params = params + list(embedder.parameters()) opt = self.instantiate_optimizer_from_config(params, lr, self.optimizer_config) if self.scheduler_config is not None: scheduler = instantiate_from_config(self.scheduler_config) print("Setting up LambdaLR scheduler...") scheduler = [ { "scheduler": LambdaLR(opt, lr_lambda=scheduler.schedule), "interval": "step", "frequency": 1, } ] return [opt], scheduler return opt @torch.no_grad() def sample( self, cond: Dict, uc: Union[Dict, None] = None, batch_size: int = 16, shape: Union[None, Tuple, List] = None, **kwargs, ): randn = torch.randn(batch_size, *shape).to(self.device) denoiser = lambda input, sigma, c: self.denoiser( self.model, input, sigma, c, **kwargs ) samples = self.sampler(denoiser, randn, cond, uc=uc) return samples @torch.no_grad() def log_conditionings(self, batch: Dict, n: int) -> Dict: """ Defines heuristics to log different conditionings. These can be lists of strings (text-to-image), tensors, ints, ... """ image_h, image_w = batch[self.input_key].shape[2:] log = dict() for embedder in self.conditioner.embedders: if ( (self.log_keys is None) or (embedder.input_key in self.log_keys) ) and not self.no_cond_log: x = batch[embedder.input_key][:n] if isinstance(x, torch.Tensor): if x.dim() == 1: # class-conditional, convert integer to string x = [str(x[i].item()) for i in range(x.shape[0])] xc = log_txt_as_img((image_h, image_w), x, size=image_h // 4) elif x.dim() == 2: # size and crop cond and the like x = [ "x".join([str(xx) for xx in x[i].tolist()]) for i in range(x.shape[0]) ] xc = log_txt_as_img((image_h, image_w), x, size=image_h // 20) else: raise NotImplementedError() elif isinstance(x, (List, ListConfig)): if isinstance(x[0], str): # strings xc = log_txt_as_img((image_h, image_w), x, size=image_h // 20) else: raise NotImplementedError() else: raise NotImplementedError() log[embedder.input_key] = xc return log @torch.no_grad() def log_images( self, batch: Dict, N: int = 8, sample: bool = True, ucg_keys: List[str] = None, **kwargs, ) -> Dict: conditioner_input_keys = [e.input_key for e in self.conditioner.embedders] if ucg_keys: assert all(map(lambda x: x in conditioner_input_keys, ucg_keys)), ( "Each defined ucg key for sampling must be in the provided conditioner input keys," f"but we have {ucg_keys} vs. {conditioner_input_keys}" ) else: ucg_keys = conditioner_input_keys log = dict() x = self.get_input(batch) c, uc = self.conditioner.get_unconditional_conditioning( batch, force_uc_zero_embeddings=ucg_keys if len(self.conditioner.embedders) > 0 else [], ) sampling_kwargs = {} N = min(x.shape[0], N) x = x.to(self.device)[:N] log["inputs"] = x z = self.encode_first_stage(x) log["reconstructions"] = self.decode_first_stage(z) log.update(self.log_conditionings(batch, N)) for k in c: if isinstance(c[k], torch.Tensor): c[k], uc[k] = map(lambda y: y[k][:N].to(self.device), (c, uc)) if sample: with self.ema_scope("Plotting"): samples = self.sample( c, shape=z.shape[1:], uc=uc, batch_size=N, **sampling_kwargs ) samples = self.decode_first_stage(samples) log["samples"] = samples return log