import os import torch from collections import OrderedDict from abc import ABC, abstractmethod from . import networks class BaseModel(ABC): """This class is an abstract base class (ABC) for models. To create a subclass, you need to implement the following five functions: -- <__init__>: initialize the class; first call BaseModel.__init__(self, opt). -- : unpack data from dataset and apply preprocessing. -- : produce intermediate results. -- : calculate losses, gradients, and update network weights. -- : (optionally) add model-specific options and set default options. """ def __init__(self, opt): """Initialize the BaseModel class. Parameters: opt (Option class)-- stores all the experiment flags; needs to be a subclass of BaseOptions When creating your custom class, you need to implement your own initialization. In this function, you should first call Then, you need to define four lists: -- self.loss_names (str list): specify the training losses that you want to plot and save. -- self.model_names (str list): define networks used in our training. -- self.visual_names (str list): specify the images that you want to display and save. -- self.optimizers (optimizer list): define and initialize optimizers. You can define one optimizer for each network. If two networks are updated at the same time, you can use itertools.chain to group them. See cycle_gan_model.py for an example. """ self.opt = opt self.gpu_ids = opt.gpu_ids self.isTrain = opt.isTrain self.device = torch.device('cuda:{}'.format(self.gpu_ids[0])) if self.gpu_ids else torch.device('cpu') # get device name: CPU or GPU self.save_dir = os.path.join(opt.checkpoints_dir, opt.name) # save all the checkpoints to save_dir if opt.preprocess != 'scale_width': # with [scale_width], input images might have different sizes, which hurts the performance of cudnn.benchmark. torch.backends.cudnn.benchmark = True self.loss_names = [] self.model_names = [] self.visual_names = [] self.optimizers = [] self.image_paths = [] self.metric = 0 # used for learning rate policy 'plateau' @staticmethod def modify_commandline_options(parser, is_train): """Add new model-specific options, and rewrite default values for existing options. Parameters: parser -- original option parser is_train (bool) -- whether training phase or test phase. You can use this flag to add training-specific or test-specific options. Returns: the modified parser. """ return parser @abstractmethod def set_input(self, input): """Unpack input data from the dataloader and perform necessary pre-processing steps. Parameters: input (dict): includes the data itself and its metadata information. """ pass @abstractmethod def forward(self): """Run forward pass; called by both functions and .""" pass @abstractmethod def optimize_parameters(self): """Calculate losses, gradients, and update network weights; called in every training iteration""" pass def setup(self, opt): """Load and print networks; create schedulers Parameters: opt (Option class) -- stores all the experiment flags; needs to be a subclass of BaseOptions """ if self.isTrain: self.schedulers = [networks.get_scheduler(optimizer, opt) for optimizer in self.optimizers] if not self.isTrain or opt.continue_train: load_suffix = 'iter_%d' % opt.load_iter if opt.load_iter > 0 else opt.epoch self.load_networks(load_suffix) self.print_networks(opt.verbose) def eval(self): """Make models eval mode during test time""" for name in self.model_names: if isinstance(name, str): net = getattr(self, 'net_' + name) net.eval() def test(self): """Forward function used in test time. This function wraps function in no_grad() so we don't save intermediate steps for backprop It also calls to produce additional visualization results """ with torch.no_grad(): self.forward() self.compute_visuals() def compute_visuals(self): """Calculate additional output images for visdom and HTML visualization""" pass def get_image_paths(self): """ Return image paths that are used to load current data""" return self.image_paths def update_learning_rate(self): """Update learning rates for all the networks; called at the end of every epoch""" old_lr = self.optimizers[0].param_groups[0]['lr'] for scheduler in self.schedulers: if self.opt.lr_policy == 'plateau': scheduler.step(self.metric) else: scheduler.step() lr = self.optimizers[0].param_groups[0]['lr'] print('learning rate %.7f -> %.7f' % (old_lr, lr)) def get_current_visuals(self): """Return visualization images. train.py will display these images with visdom, and save the images to a HTML""" visual_ret = OrderedDict() for name in self.visual_names: if isinstance(name, str): visual_ret[name] = getattr(self, name) return visual_ret def get_current_losses(self): """Return traning losses / errors. train.py will print out these errors on console, and save them to a file""" errors_ret = OrderedDict() for name in self.loss_names: if isinstance(name, str): errors_ret[name] = float(getattr(self, 'loss_' + name)) # float(...) works for both scalar tensor and float number return errors_ret def save_networks(self, epoch): """Save all the networks to the disk. Parameters: epoch (int) -- current epoch; used in the file name '%s_net_%s.pth' % (epoch, name) """ for name in self.model_names: if isinstance(name, str): save_filename = '%s_net_%s.pth' % (epoch, name) save_path = os.path.join(self.save_dir, save_filename) net = getattr(self, 'net_' + name) if len(self.gpu_ids) > 0 and torch.cuda.is_available(): torch.save(net.module.cpu().state_dict(), save_path) net.cuda(self.gpu_ids[0]) else: torch.save(net.cpu().state_dict(), save_path) def __patch_instance_norm_state_dict(self, state_dict, module, keys, i=0): """Fix InstanceNorm checkpoints incompatibility (prior to 0.4)""" key = keys[i] if i + 1 == len(keys): # at the end, pointing to a parameter/buffer if module.__class__.__name__.startswith('InstanceNorm') and \ (key == 'running_mean' or key == 'running_var'): if getattr(module, key) is None: state_dict.pop('.'.join(keys)) if module.__class__.__name__.startswith('InstanceNorm') and \ (key == 'num_batches_tracked'): state_dict.pop('.'.join(keys)) else: self.__patch_instance_norm_state_dict(state_dict, getattr(module, key), keys, i + 1) def load_networks(self, epoch): """Load all the networks from the disk. Parameters: epoch (int) -- current epoch; used in the file name '%s_net_%s.pth' % (epoch, name) """ for name in self.model_names: if isinstance(name, str): load_filename = '%s_net_%s.pth' % (epoch, name) load_path = os.path.join(self.save_dir, load_filename) net = getattr(self, 'net_' + name) if isinstance(net, torch.nn.DataParallel): net = net.module print('loading the model from %s' % load_path) # if you are using PyTorch newer than 0.4 (e.g., built from # GitHub source), you can remove str() on self.device state_dict = torch.load(load_path, map_location=str(self.device)) if hasattr(state_dict, '_metadata'): del state_dict._metadata # patch InstanceNorm checkpoints prior to 0.4 for key in list(state_dict.keys()): # need to copy keys here because we mutate in loop self.__patch_instance_norm_state_dict(state_dict, net, key.split('.')) net.load_state_dict(state_dict) def print_networks(self, verbose): """Print the total number of parameters in the network and (if verbose) network architecture Parameters: verbose (bool) -- if verbose: print the network architecture """ print('---------- Networks initialized -------------') for name in self.model_names: if isinstance(name, str): net = getattr(self, 'net_' + name) num_params = 0 for param in net.parameters(): num_params += param.numel() if verbose: print(net) print('[Network %s] Total number of parameters : %.3f M' % (name, num_params / 1e6)) print('-----------------------------------------------') def set_requires_grad(self, nets, requires_grad=False): """Set requies_grad=Fasle for all the networks to avoid unnecessary computations Parameters: nets (network list) -- a list of networks requires_grad (bool) -- whether the networks require gradients or not """ if not isinstance(nets, list): nets = [nets] for net in nets: if net is not None: for param in net.parameters(): param.requires_grad = requires_grad