ShigekiKarita

sudo add-apt-repository ppa:graphics-drivers/ppa
sudo apt-get --purge remove "nvidia*"
sudo apt-get --purge remove "cuda*"

wget http://developer.download.nvidia.com/compute/cuda/7.5/Prod/local_installers/cuda-repo-ubuntu1404-7-5-local_7.5-18_amd64.deb
sudo dpkg -i cuda-repo-ubuntu1404-7-5-local_7.5-18_amd64.deb
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install cuda