多头问题的实现推导不太理解

[frostjsy]

1、为啥分成多头后又进行的concat？

Split and concat

    Q_ = tf.concat(tf.split(Q, num_heads, axis=2), axis=0)  # (h*N, T_q, d_model/h)
    K_ = tf.concat(tf.split(K, num_heads, axis=2), axis=0)  # (h*N, T_k, d_model/h)
    V_ = tf.concat(tf.split(V, num_heads, axis=2), axis=0)  # (h*N, T_k, d_model/h)

2、为啥下面的这个操作等价于多头的拼接
outputs = tf.concat(tf.split(outputs, num_heads, axis=0), axis=2) # (N, T_q, d_model)