How do I Install CUDA on Ubuntu 18.04?

• How do I Install CUDA on Ubuntu 18.04?
  • (DON'T) Add apt repo and install CUDA Toolkit (BAD solution)
  • Download and install from official website
  • Problem: what if I want both 10.1 and 10.0?
  • Reference:

(DON'T) Add apt repo and install CUDA Toolkit (BAD solution)

# 1. do:
sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt update
sudo ubuntu-drivers autoinstall
# 2. reboot;
# 3. do:
sudo apt install nvidia-cuda-toolkit gcc-6
nvcc --version

However, this gives CUDA 9.1 which doesn't even have a corresponding CuDNN.

Download and install from official website

So you have to go to the official CUDA website and download e.g. a .deb file. Install CUDA 10.1:

sudo dpkg -i cuda-repo-ubuntu1804_10.1.105-1_amd64.deb
sudo apt-key adv --fetch-keys https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/7fa2af80.pub
sudo apt-get update
sudo apt-get install cuda

Now everything broke: apt cannot fix itself.

sudo apt --fix-broken install will not work, but:

sudo apt-get -o Dpkg::Options::="--force-overwrite" install --fix-broken

then apt remove everything including the old and new CUDA. then reboot and reinstall CUDA 10.1

Problem: what if I want both 10.1 and 10.0?

Just get another network .deb file from official website and in the final step:

sudo apt-get install cuda-10-0

Reference:

• How do I Install CUDA on Ubuntu 18.04?
• Failed installation of package breaks apt-get