I installed Darktable in the past through Ubuntu Software Center and it worked perfectly. However, in the Darktable preferences tab, OpenCL was not enabled.
I really want to have OpenCl enabled as it boosts Darktable's performance.
Thus I made sure I had the correct NVIDIA driver that allows OpenCL configuration enabled and tried running
darkatbe-cltest, which failed and showed this error message:
darktable-cltest not known You can install it with sudo apt install darktable
I was a bit confused, because I already had Darktable installed as described above.
But I did proceed with
sudo apt install darktable, which installed a new version of Darktable on my computer.
I also used
sudo add-apt-repository ppa:pmjdebruijn/darktable-release, in order to update to the newer version. Oddly, this new version now supports OpenCL!
Now I have 2 different versions of Darktable on my computer, both version 2.6.2. However, one supports OpenCL, while the other does not. Also the layout of the two versions is slightly different (different font size and padding).
When I run Synaptic, I can only see one version of Darktable, the one installed from the terminal.
And when I try to find packages installed through Ubuntu Software Center, like Discord, I can't find them in Synaptic.
Because I thought Ubuntu Software Center was a GUI of the terminal, it is a bit strange not to find every package installed in Ubuntu Software Center.
(NB: I have to mention that I did run
sudo apt-get update && sudo apt upgrade a few times and also updated through Synaptic some of the packages I saw there.)