举例说明PyTorch函数torch.cat与torch.stack的区别

谁借莪１个温暖的怀抱￠ 2024-03-08 02:29 143阅读 0赞

## 一、torch.cat与torch.stack的区别 ##

`torch.cat`用于在**给定的维度**上连接多个张量，它将这些张量沿着指定维度堆叠在一起。

`torch.stack`用于在**新的维度**上堆叠多个张量，它会创建一个新的维度，并将这些张量沿着这个新维度堆叠在一起。

## 二、torch.cat ##

![在这里插入图片描述][8f76ef6a976345eb8b59e81a00fce15c.jpeg_pic_center]

#### Example1： ####

import torch
    
    tensor1 = torch.tensor([[1, 2], [3, 4]])
    tensor2 = torch.tensor([[5, 6], [7, 8]])
    
    result1 = torch.cat((tensor1, tensor2), dim=0)
    result2 = torch.cat((tensor1, tensor2), dim=1)
    
    print(result1.shape)
    print(result1)
    print(result2.shape)
    print(result2)

torch.Size([4, 2])
    tensor([[1, 2],
            [3, 4],
            [5, 6],
            [7, 8]])
    torch.Size([2, 4])
    tensor([[1, 2, 5, 6],
            [3, 4, 7, 8]])

## 三、torch.stack ##

![在这里插入图片描述][fe63a9d2f3c7449496184abba1c50580.jpeg_pic_center]

#### Example1： ####

import torch
    
    tensor1 = torch.tensor([1, 2, 3])
    tensor2 = torch.tensor([4, 5, 6])
    
    result1 = torch.stack((tensor1, tensor2), dim=0)
    result2 = torch.stack((tensor1, tensor2), dim=1)
    
    print(result1.shape)
    print(result1)
    print(result2.shape)
    print(result2)

torch.Size([2, 3])
    tensor([[1, 2, 3],
            [4, 5, 6]])
    torch.Size([3, 2])
    tensor([[1, 4],
            [2, 5],
            [3, 6]])

#### Example2： ####

import torch
    
    tensor1 = torch.tensor([[1, 2], [3, 4], [5, 6]])
    tensor2 = torch.tensor([[7, 8], [9, 10], [11, 12]])
    tensor3 = torch.tensor([[13, 14], [15, 16], [17, 18]])
    
    result1 = torch.stack((tensor1, tensor2, tensor3), dim=0)
    result2 = torch.stack((tensor1, tensor2, tensor3), dim=1)
    
    print(result1.shape)
    print(result1)
    print(result2.shape)
    print(result2)

torch.Size([3, 3, 2])
    tensor([[[ 1,  2],
             [ 3,  4],
             [ 5,  6]],
    
            [[ 7,  8],
             [ 9, 10],
             [11, 12]],
    
            [[13, 14],
             [15, 16],
             [17, 18]]])
    torch.Size([3, 3, 2])
    tensor([[[ 1,  2],
             [ 7,  8],
             [13, 14]],
    
            [[ 3,  4],
             [ 9, 10],
             [15, 16]],
    
            [[ 5,  6],
             [11, 12],
             [17, 18]]])

[8f76ef6a976345eb8b59e81a00fce15c.jpeg_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/08/5aceb49944c34374a83890d2a9dde121.png
[fe63a9d2f3c7449496184abba1c50580.jpeg_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/08/d4e3016861ce4d5fbf06fa2f221a2ebc.png