How to install CUDA 6.5 on Ubuntu 14.04

Installing CUDA is becoming increasingly easier on Ubuntu. I think I keep hitting problems because I am usually updating from an older NVIDIA graphics driver or CUDA version. NVIDIA continues to be quite bad at providing error-free upgrades. Anyway, this is what worked for me:

• Do not try to install any of the NVIDIA drivers or CUDA packages that are in the Ubuntu repositories. I wasted a day with the errors these operations threw up!

• Uninstall all CUDA packages and NVIDIA drivers you may have on your Ubuntu system.

• Download the CUDA .deb package for Ubuntu 14.04 from here. For me, it was a cuda-repo-ubuntu1404_6.5-14_amd64.deb file.

• The .deb file just adds a CUDA repository maintained by NVIDIA. Install this .deb file and update:

$ sudo gdebi cuda-repo-ubuntu1404_6.5-14_amd64.deb
$ sudo apt-get update

• Installing CUDA now is easy as this:

$ sudo apt-get install cuda

This is a big install, it will install everything including a nvidia-340 driver that actually worked and NVIDIA NSight. After the install, reboot the computer. Your CUDA is ready for work now 😊

Note: I tried this on two systems. On one, it installed without any problem. On the other, it gave an error of unmet dependencies. I have described here how I solved this problem.

Tried with: NVIDIA GeForce GTS 250 and NVIDIA GTX Titan