In Tensorflow, how to use tf.gather() for the last dimension?

Question

I am trying to gather slices of a tensor in terms of the last dimension for partial connection between layers. Because the output tensor\'s shape is [batch_size, h, w,

Answer 1

Yet another solution using tf.unstack(...), tf.gather(...) and tf.stack(..)

Code:

import tensorflow as tf
import numpy as np

shape = [2, 2, 2, 10] 
L = np.arange(np.prod(shape))
L = np.reshape(L, shape)

indices = [0, 2, 3, 8]
axis = -1 # last dimension

def gather_axis(params, indices, axis=0):
    return tf.stack(tf.unstack(tf.gather(tf.unstack(params, axis=axis), indices)), axis=axis)

print(L)
with tf.Session() as sess:
    partL = sess.run(gather_axis(L, indices, axis))
    print(partL)

Result:

L = 
[[[[ 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]]

  [[60 61 62 63 64 65 66 67 68 69]
   [70 71 72 73 74 75 76 77 78 79]]]]

partL = 
[[[[ 0  2  3  8]
   [10 12 13 18]]

  [[20 22 23 28]
   [30 32 33 38]]]


 [[[40 42 43 48]
   [50 52 53 58]]

  [[60 62 63 68]
   [70 72 73 78]]]]