两个tensor作为另一个tensor的索引

形如 tensor[tensor, tensor] 的理解如下：

首先看一段代码：

import torch
S=torch.tensor(range(60)).reshape(3,4,5)
print(S)
A=[[0,1,2],
   [2,1,2],
   [0,1,2]]

B=[[1,0,2],
   [2,1,3],
   [0,1,3]]
c=S[A,B]
print(c)
print(c.shape)

程序的输出如下：

tensor([[[ 0,  1,  2,  3,  4],
         [ 5,  6,  7,  8,  9],
         [10, 11, 12, 13, 14],
         [15, 16, 17, 18, 19]],

        [[20, 21, 22, 23, 24],
         [25, 26, 27, 28, 29],
         [30, 31, 32, 33, 34],
         [35, 36, 37, 38, 39]],

        [[40, 41, 42, 43, 44],
         [45, 46, 47, 48, 49],
         [50, 51, 52, 53, 54],
         [55, 56, 57, 58, 59]]])
tensor([[[ 5,  6,  7,  8,  9],
         [20, 21, 22, 23, 24],
         [50, 51, 52, 53, 54]],

        [[50, 51, 52, 53, 54],
         [25, 26, 27, 28, 29],
         [55, 56, 57, 58, 59]],

        [[ 0,  1,  2,  3,  4],
         [25, 26, 2