在 Tensorflow 中，如何将 tf.gather() 用于最后一个维度? [英] In Tensorflow, how to use tf.gather() for the last dimension?

问题描述

我试图根据层之间的部分连接的最后一个维度来收集张量的切片.因为输出张量的形状是[batch_size, h, w,depth]，所以我想根据最后一个维度来选择切片，比如

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, depth], I want to select slices based on the last dimension, such as

# L is intermediate tensor
partL = L[:, :, :, [0,2,3,8]]

然而，tf.gather(L, [0, 2,3,8]) 似乎只适用于第一维(对吧?)谁能告诉我怎么做?

However, tf.gather(L, [0, 2,3,8]) seems to only work for the first dimension (right?) Can anyone tell me how to do it?

推荐答案

这里有一个跟踪错误来支持这个用例:https://github.com/tensorflow/tensorflow/issues/206

There's a tracking bug to support this use-case here: https://github.com/tensorflow/tensorflow/issues/206

现在您可以:

1. 转置您的矩阵，以便首先收集维度(转置很昂贵)

1. transpose your matrix so that dimension to gather is first (transpose is expensive)

将你的张量重塑为 1d(重塑是廉价的)并将你的收集列索引转换为线性索引的单个元素索引列表，然后重塑回来

reshape your tensor into 1d (reshape is cheap) and turn your gather column indices into a list of individual element indices at linear indexing, then reshape back

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