reduce_sum Computes the sum of elements across dimensions of a tensor. - keepdims=False The rank of the tensor is reduced by 1 for each of the entries in axis A = tf.constant([[[1, 2, 3]], [[4, 5, 6]]]) tf.reduce_sum(A)=21 tf.reduce_sum(A, 0)=[[5 7 9]] tf.reduce_sum(A, 1)=[[1 2 3] [4 5 6]] tf.reduce_sum(A, 2)=[[ 6] [15]] - keepdims=True The reduced dimensions are retained with length 1. tf.reduc..