openCL installation documentation

[ondrejkrejci]

@NikoOinonen - I have checked the opencl installation and it seems that we do not need the sudo installation. This is what I did under anaconda environment (py-3.12.8) and it is working fine. Could we maybe update the documentation?

pip install pyqt5
pip install ppafm[opencl]
ppafm-gui

[NikoOinonen]

What distro/version is this? I remember I had the problem with Ubuntu 22.xx before.

[ondrejkrejci]

It is Pop OS based on ubuntu 22.04 LTS. Interesting, maybe we could put just note there. I do not know, if anaconda helped with something, or Python 3.12 was the key.

[NikoOinonen]

I do not know, if anaconda helped with something

Yes, I think I had is also working with Anaconda before without any additional packages.

Actually, starting from Ubuntu 24.04, the system pip by default cannot be used for installing new packages, because the Python environment is being managed by the OS. The recommended way now is to always create a self-contained environment, either with venv or conda/mamba. So we could change the installation documentation to primarily guide how to install it in a virtual environment.

[NikoOinonen]

@mondracek mentioned having difficulties installing ppafm with OpenCL.

If no other driver works, then using the POCL driver which should work with any CPU is probably the easiest option. It's available in the Ubuntu repositories with:

sudo apt install pocl-opencl-icd

If you cannot use sudo, then binaries are also available through conda on conda-forge, although it didn't work on my system. Update: it does work if I also install pyopencl from conda, but it's a bit inconvenient since you need to manually uninstall the version installed by pip during ppafm installation first.

[NikoOinonen]

I also did some testing on my AMD GPU on the different options for getting OpenCL working on Linux (testing on Mint 22.1, equivalent to Ubuntu 24.04). Currently there's two ways that should work, depending on what device you have:

1. Mesa rusticl

Install from the repositories:

sudo apt install mesa-opencl-icd

The driver is not enabled by default yet in the standard distribution because it's new and not considered stable yet. To enable it set the environment variable RUSTICL_ENABLE="radeonsi,iris" when you run ppafm, or set it permanently for your user by adding it to your .profile:

echo -e '\nexport RUSTICL_ENABLE="radeonsi,iris"' >> ~/.profile

You may also get the old mesa Clover driver as an option when listing devices with ppafm-gui --list-devices, but it does not work on any modern GPUs, so make sure to select the rusticl device:

Available OpenCL platforms:
Platform 0: rusticl
Platform 1: Clover

2. AMD ROCm

Mostly works only on the latest high-end desktop and server GPUs, check compatibility. Enable the repositories according to instructions, and make sure to install at least the opencl package:

sudo apt install rocm-opencl-runtime

The device should now be listed by ppafm-gui --list-devices as

Available OpenCL platforms:
Platform 0: AMD Accelerated Parallel Processing