易错点:注意带上参数axis,否则的话,默认对全部元素求和,返回一个数值int
参考:https://www.jianshu.com/p/30b40b504bae
tf.reduce_sum( input_tensor, axis=None, keepdims=None, name=None, reduction_indices=None, keep_dims=None)
下面是个 2 * 3 * 4 的tensor
[[[ 1 2 3 4] [ 5 6 7 8] [ 9 10 11 12]], [[ 13 14 15 16] [ 17 18 19 20] [ 21 22 23 24]]]
tf.reduce_sum(tensor, axis=0) axis=0 , 说明是对第一个维度进行求和(也可理解成压缩!),即2*3*4中的2,压缩,结果得到3*4的tensor
[[1+13 2+14 3+15 4+16]
[5+17 6+18 7+19 8+20]
[9+21 10+22 11+23 12+24]]