transforms_ = [ transforms.Resize(int(opt.size*1.12), Image.BICUBIC), 
                transforms.RandomCrop(opt.size), 
                transforms.RandomHorizontalFlip(), 
                transforms.ToTensor(), 
                transforms.Normalize((0.5,0.5,0.5), (0.5,0.5,0.5)) ] # 将三个通道 `Normalize`

# ImageDataset 是我自己写的类

dataloader = DataLoader(ImageDataset(opt.dataroot, transforms_=transforms_, unaligned=True), 
                        batch_size=opt.batchSize, shuffle=True, num_workers=opt.n_cpu)