tf.segment_sum和tf.unsorted_segment_sum实例

import tensorflow as tf
c = tf.constant([[1,2,3,4], [-1,-2,-3,-4], [5,6,7,8]])
result = tf.segment_sum(c, tf.constant([0, 0, 1]))#第二个参数长度必须为3
result_ = tf.segment_sum(c, tf.constant([0, 1, 1]))
result__ = tf.segment_sum(c, tf.constant([0, 1, 2]))
result2 = tf.unsorted_segment_sum(c, tf.constant([2, 1, 1]),3)#第二个参数长度必须为3
result3 = tf.unsorted_segment_sum(c, tf.constant([1, 0, 1]),2)
#result4 = tf.unsorted_segment_sum(c, tf.constant([2, 0, 1]),2) #错误，segment_ids[0] = 2 is out of range [0, 2)
result4 = tf.unsorted_segment_sum(c, tf.constant([2, 0, 1]),3)
result5 = tf.unsorted_segment_sum(c, tf.constant([3, 1, 0]),5)
sess = tf.Session()
print("result")
print(sess.run(result))
print("result_")
print(sess.run(result_))
print("result__")
print(sess.run(result__))
print("result2")
print(sess.run(result2))
print("result3")
print(sess.run(result3))
print("result4")
print(sess.run(result4))
print("result5")
print(sess.run(result5))

result
[[0 0 0 0]
[5 6 7 8]]
result_
[[1 2 3 4]
[4 4 4 4]]
result__
[[ 1 2 3 4]
[-1 -2 -3 -4]
[ 5 6 7 8]]
result2
[[0 0 0 0]
[4 4 4 4]
[1 2 3 4]]
result3
[[-1 -2 -3 -4]
[ 6 8 10 12]]
result4
[[-1 -2 -3 -4]
[ 5 6 7 8]
[ 1 2 3 4]]
result5
[[ 5 6 7 8]
[-1 -2 -3 -4]
[ 0 0 0 0]
[ 1 2 3 4]
[ 0 0 0 0]]