Adding openmc.read_source_file

[pshriwise]

Description

We currently have the ability to write a list of openmc.SourceParticle objects to an HDF5 file, but no ability to read a file into a list of those objects that I'm aware of. I found it useful to be able to do so today and added that function so I thought I'd contribute it
here.

I added testing of this function to test_source_file.py, but left the checks using h5py in place as it hammers on that file spec a bit so I think it's still useful to have them around.

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)

[gonuke]

I thought this did exist somewhere... I'll have to dig and take a look. That's how we tested it when we introduced the feature???

[paulromano]

Thanks @pshriwise!

[gonuke]

How does this relate to openmc.settings.surf_source_read(). While this may be named poorly, I think it might do a similar thing that you are aiming for here?

[pshriwise]

How does this relate to openmc.settings.surf_source_read(). While this may be named poorly, I think it might do a similar thing that you are aiming for here?

openmc.Settings.surf_source_read is a dictionary on the openmc.Settings class that is serialized into the XML. It contains a path to a source file to be read into the OpenMC simulation on initialization of the problem. In contrast, this provides a way to read a general source file (fission source, surface source, what have you) into the Python API. It came in handy for some work I was doing. While this is something that we can interact with via the openmc.lib module using openmc.lib.sample_external_source, it seems a reasonable mirror to the write_source_file function that's currently part of the Python API.