三重损失tensorflow，其中锚-正对是预先定义的

Question

我正在尝试在Tensorflow中实现三元组损失，其中三元组是通过在线挖掘的方式获得的。在我的特殊问题中，我已经有了anchor(image) - positive(text)对。我想要实现的是在批处理中拥有image-text对的三元组anchor(image) - positive(text) - negative(text)和anchor(text) - positive(image) - negative(image)。

如果您需要任何进一步的信息，请让我知道，并期待您的答案！

Answer 1

我发现这就是我需要的解决方案：

def compute_loss(images: tf.Tensor, texts: tf.Tensor, margin: float) -> tf.Tensor:
    with tf.variable_scope(name_or_scope="loss"):
        scores = tf.matmul(images, texts, transpose_b=True)
        diagonal = tf.diag_part(scores)
        # Compare every diagonal score to scores in its column i.e
        # All contrastive images for each sentence
        cost_s = tf.maximum(0.0, margin - tf.reshape(diagonal, [-1, 1]) + scores)
        # Compare every diagonal score to scores in its row i.e
        # All contrastive sentences for each image
        cost_im = tf.maximum(0.0, margin - diagonal + scores)

        # Clear diagonals
        cost_s = tf.linalg.set_diag(cost_s, tf.zeros(tf.shape(cost_s)[0]))
        cost_im = tf.linalg.set_diag(cost_im, tf.zeros(tf.shape(cost_im)[0]))

        # For each positive pair (i,s) sum over the negative images
        cost_s = tf.reduce_sum(cost_s, axis=1)
        # For each positive pair (i,s) sum over the negative texts
        cost_im = tf.reduce_sum(cost_im, axis=0)

        triplet_loss = tf.reduce_mean(cost_s) + tf.reduce_mean(cost_im)

        return triplet_loss