How do system requirements work?

[twrightsman]

I'm a bit confused on how the system-requirements section works in pixi.toml.

When I specify:

[system-requirements]
cuda = "11"

I assume this means CUDA 11 is required by this environment? How could I specify any version greater than 11? It seems pixi requires an actual version number in this section.

[baszalmstra]

System requirements basically configure the reference machine for your project. So any system that has at least those specs will work for your project. In essence, it sets the virtual package __cuda to __cuda=11=0 when you solve an environment. So this means that if a package requires __cuda >=11.0 it is installable. If a package requires __cuda>=12 it wont be installable.

When you run any task with pixi, it will check if the specs from your system are at least equal to or higher than the system requirements specified in your pixi.toml. So with the specification you mentioned above, if I don't have cuda or a version lower than 11, I wont be able to run your project. If I have cuda 11 or higher, I'm guaranteed that your project will run.

[twrightsman]

Got it, that makes sense. So in the current design of system requirements it is not possible to set a maximum or set of versions of virtual packages that won't work? e.g. this environment works on CUDA 11, except 11.3, but not CUDA 12.

[baszalmstra]

Not as of right now. This is something that we are looking into though. I think its related to #239 and the answers there.

[twrightsman]

Link to the new documentation on system requirements for future readers: https://prefix.dev/docs/pixi/configuration#the-system-requirements-table