def train(X, contents_Y, styles_Y, device, lr, num_epochs, lr_decay_epoch): X, styles_Y_gram, trainer = get_inits(X, device, lr, styles_Y) animator = d2l.Animator(xlabel='epoch', ylabel='loss', xlim=[10, num_epochs], ylim=[0, 20], legend=['content', 'style', 'TV'], ncols=2, figsize=(7, 2.5)) for epoch in range(num_epochs): with autograd.record(): contents_Y_hat, styles_Y_hat = extract_features( X, content_layers, style_layers) contents_l, styles_l, tv_l, l = compute_loss( X, contents_Y_hat, styles_Y_hat, contents_Y, styles_Y_gram) l.backward() trainer.step(1) if (epoch + 1) % lr_decay_epoch == 0: trainer.set_learning_rate(trainer.learning_rate * 0.8) if (epoch + 1) % 10 == 0: animator.axes[1].imshow(postprocess(X).asnumpy()) animator.add(epoch + 1, [float(sum(contents_l)), float(sum(styles_l)), float(tv_l)]) return X