Ubuntu 20.04LTS系统安装CUDA11.8、cuDNN，可进行CUDA版本切换

1. 更改为清华源并更新软件列表和依赖项
2. 安装CUDA
3. 安装cuDNN
4. CUDA版本切换
5. 更改为清华源并更新软件列表和依赖项
   https://mirrors.tuna.tsinghua.edu.cn/help/ubuntu/

默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse

deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse

deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

deb-src http://security.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

更新软件列表和必要的依赖项

sudo apt-get update # 更新软件列表
sudo apt-get install g++ # 下载g++编译器
sudo apt-get install gcc # 下载gcc编译器
sudo apt-get install make # 下载GNU Make编译器
sudo apt-get install initramfs-tools # 下载安装initramfs-tools

2. 安装CUDA
   步骤一： 下载CUDA安装包

进行CUDA和cuDNN的选择，也可以直接根据官方推荐进行下载安装。
从Nvidia官网下载CUDA https://developer.nvidia.com/cuda-downloads
下方链接，选择更多版本 https://developer.nvidia.com/cuda-toolkit-archive

接下来根据提示进行下载、安装
wget https://developer.download.nvidia.com/compute/cuda/11.8.0/local_installers/cuda_11.8.0_520.61.05_linux.run
sudo sh cuda_11.8.0_520.61.05_linux.run

步骤二： 安装CUDA安装包过程中的选择

Do you accept the above EULA? (accept / decline / quit):
是否接受最终用户许可协议，输入accept

回车键进行勾选，X就是选中，没有X就是没有选中，把安装驱动进行取消。之后向下键，回车确认

最后点击 install

出现了警告信息，对安装无影响

截图日志：

wit622@622:~/cuda$ sudo sh cuda_11.8.0_520.61.05_linux.run

[sudo] wit622 的密码：

= Summary =

Driver: Not Selected
Toolkit: Installed in /usr/local/cuda-11.8/

Please make sure that

• PATH includes /usr/local/cuda-11.8/bin
• LD_LIBRARY_PATH includes /usr/local/cuda-11.8/lib64, or, add /usr/local/cuda-11.8/lib64 to /etc/ld.so.conf and run ldconfig as root

To uninstall the CUDA Toolkit, run cuda-uninstaller in /usr/local/cuda-11.8/bin
***WARNING: Incomplete installation! This installation did not install the CUDA Driver. A driver of version at least 520.00 is required for CUDA 11.8 functionality to work.
To install the driver using this installer, run the following command, replacing with the name of this run file:
sudo .run –silent –driver

Logfile is /var/log/cuda-installer.log

也可以进入日志进行查看（位置如下）：

/var/log/cuda-installer.log

步骤三： 配置CUDA环境

sudo vim ~/.bashrc

在bashrc文件最下方，添加下入代码
（ps：这边需要注意cuda的版本，版本不同，路径的命名需修改）
export PATH=$PATH:/usr/local/cuda-11.8/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-11.8/lib64

更新环境
source ~/.bashrc

测试CUDA是否安装成功
nvcc -V
输出下述结果，表示安装成功:

wit622@622:~/cuda$ nvcc -V
nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2022 NVIDIA Corporation
Built on Wed_Sep_21_10:33:58_PDT_2022
Cuda compilation tools, release 11.8, V11.8.89
Build cuda_11.8.r11.8/compiler.31833905_0

3. 安装cuDNN
   步骤一：下载cuDNN包

例如这边选择了Download cuDNN v8.8.1 (March 8th, 2023), for CUDA 11.x
点击Local Installer for Linux x86_64 (Tar)即可下载压缩包

将压缩包，放入自定义路径后，输入命令进行解压
tar -xvf cudnn-linux-x86_64-8.8.1.3_cuda11-archive.tar.xz

解压后，输入命令，讲cuDNN对应文件拷贝至CUDA指定路径。
wit622@622:~/下载$ cd cudnn-linux-x86_64-8.8.1.3_cuda11-archive/
wit622@622:~/下载/cudnn-linux-x86_64-8.8.1.3_cuda11-archive$ ls
include lib LICENSE

sudo cp include/cudnn.h /usr/local/cuda-11.8/include sudo cp lib/libcudnn /usr/local/cuda-11.8/lib64
sudo chmod a+r /usr/local/cuda-11.8/include/cudnn.h /usr/local/cuda-11.8/lib64/libcudnn

4. CUDA版本切换
   因为后续部分项目，用的库对应的CUDA不同，无需进行修改，修改环境CUDA路径即可。例如需要11.1的CUDA，可通过修改bashrc进行修改

sudo vim ~/.bashrc
将原先的cuda-11.8注释掉，添加cuda-11.1新的环境设置，即可

cuda-11.8

export PATH=$PATH:/usr/local/cuda-11.8/bin

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-11.8/lib64

cuda-11.1

export PATH=$PATH:/usr/local/cuda-11.1/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-11.1/lib64