def get_gradients(self, loss, params): """Returns gradients of `loss` with respect to `params`. Arguments: loss: Loss tensor. params: List of variables. Returns: List of gradient tensors. Raises: ValueError: In case any gradient cannot be computed (e.g. if gradient function not implemented). """ grads = K.gradients(loss, params) if None in grads: raise ValueError('An operation has `None` for gradient. ' 'Please make sure that all of your ops have a ' 'gradient defined (i.e. are differentiable). ' 'Common ops without gradient: ' 'K.argmax, K.round, K.eval.') if hasattr(self, 'clipnorm') and self.clipnorm > 0: norm = K.sqrt(sum([K.sum(K.square(g)) for g in grads])) grads = [clip_norm(g, self.clipnorm, norm) for g in grads] if hasattr(self, 'clipvalue') and self.clipvalue > 0: grads = [K.clip(g, -self.clipvalue, self.clipvalue) for g in grads] return grads
def get_gradients(self, loss, params): """Returns gradients of `loss` with respect to `params`. Arguments: loss: Loss tensor. params: List of variables. Returns: List of gradient tensors. Raises: ValueError: In case any gradient cannot be computed (e.g. if gradient function not implemented). """ grads = K.gradients(loss, params) if None in grads: raise ValueError('An operation has `None` for gradient. ' 'Please make sure that all of your ops have a ' 'gradient defined (i.e. are differentiable). ' 'Common ops without gradient: ' 'K.argmax, K.round, K.eval.') if hasattr(self, 'clipnorm') and self.clipnorm > 0: norm = K.sqrt(sum([K.sum(K.square(g)) for g in grads])) grads = [clip_norm(g, self.clipnorm, norm) for g in grads] if hasattr(self, 'clipvalue') and self.clipvalue > 0: grads = [K.clip(g, -self.clipvalue, self.clipvalue) for g in grads] return grads
def get_gradients(self, loss, params): grads = K.gradients(loss, params) if hasattr(self, 'clipnorm') and self.clipnorm > 0: norm = K.sqrt(sum([K.sum(K.square(g)) for g in grads])) grads = [clip_norm(g, self.clipnorm, norm) for g in grads] if hasattr(self, 'clipvalue') and self.clipvalue > 0: grads = [K.clip(g, -self.clipvalue, self.clipvalue) for g in grads] return grads
def get_gradients(self, loss, params): grads = K.gradients(loss, params) if hasattr(self, 'clipnorm') and self.clipnorm > 0: norm = K.sqrt(sum([K.sum(K.square(g)) for g in grads])) grads = [clip_norm(g, self.clipnorm, norm) for g in grads] if hasattr(self, 'clipvalue') and self.clipvalue > 0: grads = [K.clip(g, -self.clipvalue, self.clipvalue) for g in grads] return grads
style_reference_features = layer_features[1:nb_tensors - 1, :, :, :] sl2 = [] for j in range(nb_style_images): sl2.append(style_loss(style_reference_features[j], combination_features,shape)) for j in range(nb_style_images): s1 = sl1[j] = sl2[j] # Improvement 4 # Geometric weighted scaling of style loss loss += (style_weights[j] / (2 ** (nb_layers - (i + 1)))) * s1 loss += total_variation_weight * total_variation_loss(combination_image) # get the gradients of the generated image wrt the loss grads = K.gradients(loss, combination_image) outputs = [loss] if type(grads) in {list, tuple}: outputs += grads else: outputs.append(grads) f_outputs = K.function([combination_image], outputs) def eval_loss_and_grads(x): x = x.reshape((1, img_width, img_height, 3)) outs = f_outputs([x]) loss_value = outs[0] if len(outs[1:]) == 1: