import torch from collections import OrderedDict from r_basicsr.archs import build_network from r_basicsr.losses import build_loss from r_basicsr.utils import get_root_logger from r_basicsr.utils.registry import MODEL_REGISTRY from .sr_model import SRModel @MODEL_REGISTRY.register() class SRGANModel(SRModel): """SRGAN model for single image super-resolution.""" def init_training_settings(self): train_opt = self.opt['train'] self.ema_decay = train_opt.get('ema_decay', 0) if self.ema_decay > 0: logger = get_root_logger() logger.info(f'Use Exponential Moving Average with decay: {self.ema_decay}') # define network net_g with Exponential Moving Average (EMA) # net_g_ema is used only for testing on one GPU and saving # There is no need to wrap with DistributedDataParallel self.net_g_ema = build_network(self.opt['network_g']).to(self.device) # load pretrained model load_path = self.opt['path'].get('pretrain_network_g', None) if load_path is not None: self.load_network(self.net_g_ema, load_path, self.opt['path'].get('strict_load_g', True), 'params_ema') else: self.model_ema(0) # copy net_g weight self.net_g_ema.eval() # define network net_d self.net_d = build_network(self.opt['network_d']) self.net_d = self.model_to_device(self.net_d) self.print_network(self.net_d) # load pretrained models load_path = self.opt['path'].get('pretrain_network_d', None) if load_path is not None: param_key = self.opt['path'].get('param_key_d', 'params') self.load_network(self.net_d, load_path, self.opt['path'].get('strict_load_d', True), param_key) self.net_g.train() self.net_d.train() # define losses if train_opt.get('pixel_opt'): self.cri_pix = build_loss(train_opt['pixel_opt']).to(self.device) else: self.cri_pix = None if train_opt.get('ldl_opt'): self.cri_ldl = build_loss(train_opt['ldl_opt']).to(self.device) else: self.cri_ldl = None if train_opt.get('perceptual_opt'): self.cri_perceptual = build_loss(train_opt['perceptual_opt']).to(self.device) else: self.cri_perceptual = None if train_opt.get('gan_opt'): self.cri_gan = build_loss(train_opt['gan_opt']).to(self.device) self.net_d_iters = train_opt.get('net_d_iters', 1) self.net_d_init_iters = train_opt.get('net_d_init_iters', 0) # set up optimizers and schedulers self.setup_optimizers() self.setup_schedulers() def setup_optimizers(self): train_opt = self.opt['train'] # optimizer g optim_type = train_opt['optim_g'].pop('type') self.optimizer_g = self.get_optimizer(optim_type, self.net_g.parameters(), **train_opt['optim_g']) self.optimizers.append(self.optimizer_g) # optimizer d optim_type = train_opt['optim_d'].pop('type') self.optimizer_d = self.get_optimizer(optim_type, self.net_d.parameters(), **train_opt['optim_d']) self.optimizers.append(self.optimizer_d) def optimize_parameters(self, current_iter): # optimize net_g for p in self.net_d.parameters(): p.requires_grad = False self.optimizer_g.zero_grad() self.output = self.net_g(self.lq) l_g_total = 0 loss_dict = OrderedDict() if (current_iter % self.net_d_iters == 0 and current_iter > self.net_d_init_iters): # pixel loss if self.cri_pix: l_g_pix = self.cri_pix(self.output, self.gt) l_g_total += l_g_pix loss_dict['l_g_pix'] = l_g_pix # perceptual loss if self.cri_perceptual: l_g_percep, l_g_style = self.cri_perceptual(self.output, self.gt) if l_g_percep is not None: l_g_total += l_g_percep loss_dict['l_g_percep'] = l_g_percep if l_g_style is not None: l_g_total += l_g_style loss_dict['l_g_style'] = l_g_style # gan loss fake_g_pred = self.net_d(self.output) l_g_gan = self.cri_gan(fake_g_pred, True, is_disc=False) l_g_total += l_g_gan loss_dict['l_g_gan'] = l_g_gan l_g_total.backward() self.optimizer_g.step() # optimize net_d for p in self.net_d.parameters(): p.requires_grad = True self.optimizer_d.zero_grad() # real real_d_pred = self.net_d(self.gt) l_d_real = self.cri_gan(real_d_pred, True, is_disc=True) loss_dict['l_d_real'] = l_d_real loss_dict['out_d_real'] = torch.mean(real_d_pred.detach()) l_d_real.backward() # fake fake_d_pred = self.net_d(self.output.detach()) l_d_fake = self.cri_gan(fake_d_pred, False, is_disc=True) loss_dict['l_d_fake'] = l_d_fake loss_dict['out_d_fake'] = torch.mean(fake_d_pred.detach()) l_d_fake.backward() self.optimizer_d.step() self.log_dict = self.reduce_loss_dict(loss_dict) if self.ema_decay > 0: self.model_ema(decay=self.ema_decay) def save(self, epoch, current_iter): if hasattr(self, 'net_g_ema'): self.save_network([self.net_g, self.net_g_ema], 'net_g', current_iter, param_key=['params', 'params_ema']) else: self.save_network(self.net_g, 'net_g', current_iter) self.save_network(self.net_d, 'net_d', current_iter) self.save_training_state(epoch, current_iter)