import tensorflow as tf

    pred1 = tf.slice(batch, [0, 0], [num_sam, 1])

    def uniform():
        batch2 = tf.gather(batch, tf.random.shuffle(index))
        pred2 = tf.slice(batch2, [0, 0], [num_sam, 1])
        tgt2 = tf.slice(batch2, [0, 1], [num_sam, 1])
