Ubuntu – How to make Nvidia CUDA work? (for GPU rendering in Blender)

First I switched to a console (CTRL-ALT-F1). Then I removed all nvidia stuff with

sudo apt-get autoremove --purge nvidia-*

and reinstalled the nouveau driver using

sudo apt-get install --reinstall xserver-xorg-video-nouveu

then

sudo reboot

I know this is probably not what both of us want but it is still better than no desktop at all...

My Setup (for completeness):

• OS: Ubuntu 15.04
• CPU: Intel i5-4570S
• GPU: Nvidia GeForce GT 610

In my case I found that the NVidia card was not actually turned off, and the only thing I actually needed to do to run CUDA code was:

export LD_LIBRARY_PATH=/usr/lib/nvidia-352

in the shell where I want to run it (I am assuming that globally changing the alternatives setting would break compiz, etc, etc...)

To get to this point (on a Dell Optiplex 7010, with Ubuntu 14.04, CUDA 7.5, and a GTX 980) I believe the steps were:

1. Use the PRIME Profiles tab to select Intel
2. Reboot, and select Intel as the default in the BIOS
3. Shut down the computer
4. Plug the monitors into the onboard video :)

Everything seems to be working fine so far (nvidia-smi sees the card, cuda samples run, theano uses the card, etc...)