How to change CUDA version

Question

I met this error when compiling a modified caffe version.

OpenCV static library was compiled with CUDA 7.5 support. Please, use the same version or rebuild OpenCV with CUDA 8.0

I have some old code may not compatible with CUDA8.0, so I want to change my cuda version for this error.

I modified my ~/.bash_profile like this

# export PYTHONPATH=$PYTHONPATH:/usr/local/cuda-8.0/lib64/
# export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-8.0/lib64
export PYTHONPATH=$PYTHONPATH:/usr/local/cuda-7.5/targets/x86_64-linux/lib/
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/cuda-7.5/targets/x86_64-linux/lib/

But it did't work. Still the same error. What should I do? Thanks.

Solution 1

Change your CUDA soft link to point on your desired CUDA version. For example:

ll /usr/local/cuda lrwxrwxrwx 1 root root 19 Sep 06 2017 /usr/local/cuda -> /usr/local/cuda-8.0/

Simply relink it with

Update: If the symlink already exists, use this other command:

[[email protected] ~]$ ls /usr/local/cuda
lrwxrwxrwx. 1 root root 20 Sep 14 08:03 /usr/local/cuda -> /usr/local/cuda-10.2
[[email protected] ~]$ sudo ln -sfT /usr/local/cuda/cuda-11.1/ /usr/local/cuda
[[email protected] ~]$ ls /usr/local/cuda
lrwxrwxrwx. 1 root root 26 Sep 14 13:25 /usr/local/cuda -> /usr/local/cuda/cuda-11.1/

ln -s /usr/local/cuda-7.5 /usr/local/cuda

(With the proper installation location)

Solution 2

Maybe a bit late, but I thought it might still be helpful for anyone who comes across this question. I wrote a simple bash script for switching to a different version of CUDA within the current bash session: https://github.com/phohenecker/switch-cuda

Solution 3

I solved the problem finally.

Modifying ~/.bash_profile to change the path to CUDA is the correct way. But when you changed the file, you need to relaunch the bash.

Simply source ~/.bash_profile won't work. Because source will only append the content in the file to the already existed path rather than cover it.

Solution 4

Perhaps cleaner:

sudo update-alternatives --display cuda
sudo update-alternatives --config cuda

View more solutions

Comments

[Olivia Stork]

If you use the ln -s command, it will fail if the symlink already exists. So remove the old symlink with a simple sudo rm /usr/local/cuda. (As always, be very careful with your paths when using sudo rm!)

[Shuai.Z]

I don't have the sudo permission, and got the following error ln: failed to create symbolic link ‘/usr/local/cuda-10.0/cuda-8.0’: Permission denied

[Olivia Stork]

You can also use sudo ln -sf to create OR update the symlink if it already exists. Then you won't need the rm command.

[chris]

This doesn't work for me - after a reboot, the symlink is correct, but nvidia-smi gives me the wrong version.

[yuqli]

@ChrisAnderson nvidia-smi is showing the cuda version for driver API. Use nvcc --version to find out cuda version. See here stackoverflow.com/questions/53422407/…

[Louis Maddox]

Oddly sudo ln -sf doesn't work for me (on an Ubuntu 20.04 based distro, ln version 8.30), I agree it should do... Had no effect. Cannot reproduce in my own namespace without sudo...

[Fang WU]

Great thank! Your toolkit is really useful. For the most of time, I have no access to the sudo authority.

[Mona Jalal]

@LouisMaddox check the edits I made to the post

[im0j]

This is the best answer. Simple commands, no need to install anything else, & reversible.