After CUDA is installed, the following error is reported using pytorch

UserWarning: CUDA initialization: CUDA unknown error – this may be due to an incorrectly set up environment, e.g. changing env variable CUDA_ VISIBLE_ DEVICES after program start.

Solution: after CUDA and pytorch are installed, add the following in. Bashrc

export  PATH=/usr/local/cuda-11.4/bin:$PATH
export  LD_LIBRARY_PATH=/usr/local/cuda-11.4/lib64$LD_LIBRARY_PATH
export CUDA_HOME=/usr/local/cuda-11.4/bin
export CUDA_VISIBLE_DEVICES=0,1

If there is still a problem, use sudo apt-get install NVIDIA modprobe to install it. After the installation, you can use it

Methods of checking CUDA

import torch
flag = torch.cuda.is_available()
print(flag)

Output is: True cuda normal