介绍Gather虚化方法

Gather虚化方法是一种在深度学习中常用的数据操作方法，它可以将一个张量中的指定维度上的元素按照给定的索引进行聚合，返回一个新的张量。在TensorFlow中，可以使用tf.gather函数来实现Gather虚化方法。

相关问题

reduce gather

"Reduce" and "gather" are two operations commonly used in parallel computing and distributed systems.

Reduce is an operation that takes a set of values and combines them into a single value. For example, if you have a set of numbers {1, 2, 3, 4}, you can perform a "reduce" operation to sum them up and get a single value of 10.

Gather is an operation that collects data from multiple sources and combines them into a single location. For example, if you have a distributed database with data stored across multiple nodes, you can perform a "gather" operation to collect all the data from the nodes and combine them into a single database.

In some cases, "reduce" and "gather" operations can be used together. For example, you can perform a "reduce" operation on each node in a distributed system and then perform a "gather" operation to combine the results into a single output.

gather函数

`gather`函数是一个用于从指定的Tensor中收集指定索引的值的函数。它的输入包括一个待收集的Tensor `input`，一个指定索引的Tensor `index`，以及一个指定收集维度的整数`dim`。具体而言，`gather`函数会在`input`的`dim`维度上收集`index`中所包含的索引所对应的值，并返回一个新的Tensor。 举个例子，如果我们有一个形状为(3,4)的Tensor `input`和一个形状为(2,3)的Tensor `index`，则可以使用`gather`函数从`input`中收集`index`中所包含的索引所对应的值，代码如下：

import torch

input = torch.tensor([[1,2,3,4],[5,6,7,8],[9,10,11,12]])
index = torch.tensor([[0,2,1],[2,1,0]])

output = torch.gather(input, 1, index)

print(output)

输出结果为：

tensor([[ 1,  3,  2],
        [ 7,  6,  5],
        [12, 11, 10]])

可以看到，`output`的形状为(2,3)，其中的每个值都是从`input`中收集到的对应索引的值。