vgg_network.py 文件源码

def style_loss(self, layers):
        activations = [self.activations_for_layer(i) for i in layers]
        gramians = [self.gramian_for_layer(x) for x in layers]
        # Slices are for style and synth image
        gramian_diffs = [
            tf.sub(
                tf.tile(tf.slice(g, [0, 0, 0], [self.num_style, -1, -1]), [self.num_synthesized - self.num_style + 1, 1, 1]),
                tf.slice(g, [self.num_style + self.num_content, 0, 0], [self.num_synthesized, -1, -1]))
            for g in gramians]
        Ns = [g.get_shape().as_list()[2] for g in gramians]
        Ms = [a.get_shape().as_list()[1] * a.get_shape().as_list()[2] for a in activations]
        scaled_diffs = [tf.square(g) for g in gramian_diffs]
        style_loss = tf.div(
            tf.add_n([tf.div(tf.reduce_sum(x), 4 * (N ** 2) * (M ** 2)) for x, N, M in zip(scaled_diffs, Ns, Ms)]),
            len(layers))
        return style_loss