Adding ability to set additional ww attrs from openmc.lib

[pshriwise]

Description

This adds the ability to set additional attributes of WeightWindows objects:

• survival_ratio
• max_lower_bound_ratio
• weight_cutoff
• max_splits

Fixes # (issue)

#2607

Checklist

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

[shimwell]

I notice the CI is failing with ERROR: Could not build wheels for h5py, which is required to install pyproject.toml-based projects and I have seen this on other PRs so I think this error is unrelatead to the PR.

[shimwell]

I've read through this PR and been making use of it locally. I used the script below to check that the attributes are set and change from their default values. Everything looks good to me.

import openmc
import openmc.lib
mat_water = openmc.Material()
mat_water.add_element("H", 1)
mat_water.add_element("O", 2)
mat_water.set_density("g/cm3", 1.0)
my_materials = openmc.Materials([mat_water])
outer_surface = openmc.model.RectangularParallelepiped(-300, 300, -300, 300, -300, 300, boundary_type="vacuum")
region_1 = -outer_surface
cell_1 = openmc.Cell(region=region_1)
cell_1.fill = mat_water
my_geometry = openmc.Geometry([cell_1])
space = openmc.stats.Point((0, 0, 0))
angle = openmc.stats.Isotropic()
energy = openmc.stats.Discrete([14e6], [1.0])
source = openmc.Source(space=space, angle=angle, energy=energy)
source.particle = "neutron"
mesh = openmc.RegularMesh().from_domain(domain=my_geometry)
mesh.dimension = (2,2,2)
mesh_filter = openmc.MeshFilter(mesh)
flux_tally = openmc.Tally(name="flux tally")
flux_tally.filters = [mesh_filter]
flux_tally.scores = ["flux"]
flux_tally.id = 55
my_tallies = openmc.Tallies()
my_tallies.append(flux_tally)
tallies = openmc.Tallies([flux_tally])
my_settings = openmc.Settings()
my_settings.run_mode = "fixed source"
my_settings.source = source
my_settings.particles = 120
my_settings.batches = 10
my_settings.output = {'tallies': False}
my_model = openmc.Model(my_geometry, my_materials, my_settings, my_tallies)
my_model.export_to_xml()
with openmc.lib.run_in_memory():
    tally = openmc.lib.tallies[55]
    wws = openmc.lib.WeightWindows.from_tally(tally)
    wws.max_split = 25
    wws.survival_ratio = 26
    wws.max_lower_bound_ratio = 27
    wws.weight_cutoff = 28
    for i in range(5):
        openmc.lib.run()
        wws.update_magic(tally)
        openmc.lib.settings.particles = int(openmc.lib.settings.particles * 1.5)
        openmc.lib.export_weight_windows(filename=f'weight_windows{str(i).zfill(2)}.h5')
        openmc.lib.statepoint_write(filename=f'statepoint_simulation_{str(i).zfill(2)}.h5')
        openmc.lib.settings.weight_windows_on = True
wws2 = openmc.hdf5_to_wws(f'weight_windows{str(i).zfill(2)}.h5')
print(wws2)

[paulromano]

All looks straightforward to me. Thanks @pshriwise!

[paulromano]

@pshriwise Can you push an empty commit to this branch to restart CI from a fresh state?

[shimwell]

🎉 CI is passing on this PR. Seeing as Paul has approved I'm going to go ahead and merge while I'm here