Scikit build core wheel minimal

[jon-proximafusion]

test PR trying to reduce this openmc PR to a more minimal PR that only does the scikit build core changes

FYI @ahnaf-tahmid-chowdhury

[ahnaf-tahmid-chowdhury]

Tests are failing due to an AssertionError. I believe all necessary files have been copied to this branch correctly, but I noticed some changes that need to be reviewed. Please check which files should be removed.

Regarding OpenMC's integration with NCrystal, building OpenMC with NCrystal creates a dependency on libNCrystal.so. While this currently works, it's not an efficient approach since we have to load it through subprocess. One possible fix is setting LD_LIBRARY_PATH, but that introduces additional complexity. Moreover, this setup makes OpenMC's core dependent on python, which is not ideal.

I suggest building NCrystal from source instead of relying on the ncrystal package. The issue with ncrystal is that it installs both ncrystal-core and ncrystal-python, and ncrystal-core includes libNCrystal.so, which is not used by libopenmc.so. Instead, libopenmc.so will use the libNCrystal.so copied to openmc.libs by auditwheel, leading to unnecessary duplication.

Let me know how you'd like to proceed.

[shimwell]

I don't think openmc will accept the PR if ncrystal is added as a build time or even as a dependency in the pyproject.toml file.

I agree with your recommendation of building NCrystal from source.

Just wondering if we can do the building NCrystal from source as a separate PR directly to openmc? and then once that is merged we come back to this packaging branch and benfit from those changes.

Are there any changes that can be done on the NCrystal side to makes this easier?

[shimwell]

I have merged in the recent changes that are now in openmc develop branch and solved merge conflicts.

I think we should build on this PR @ahnaf-tahmid-chowdhury and see if we can get a minimal scikit build core working then PR this branch into openmc

[tkittel]

I took a quick look at the "Files changed" (since I am looking forward to this PR!), and still see some ncrystal related stuff introduced. Is that needed any longer?

[shimwell]

I took a quick look at the "Files changed" (since I am looking forward to this PR!), and still see some ncrystal related stuff introduced. Is that needed any longer?

Do you have time to push ti this branch with the ncrystal related changes needed @tkittel

[tkittel]

Not at the moment unfortunately, I have some other issues I have to work on that I have postponed too many times :-)

But I simply meant that I don't think this PR need to add some NCrystal lib related stuff any longer, presumably? And looking at the diff it does add something.

[ahnaf-tahmid-chowdhury]

I am checking.