TypeError on _dll.openmc_nuclide_collapse_rate

[shimwell]

Just making use of openmc.lib.nuclide.collapse_rate which calls _dll.openmc_nuclide_collapse_rate and then errors with a ctypes.ArgumentError: argument 1: TypeError: wrong type error

It looks like the self_index is the wrong type and causes the code to crash.

Link to line in source code

Bug Description

Steps to Reproduce

import numpy as np
import openmc
import openmc.lib
from ctypes import c_int, c_double
import openmc.deplete

mat1 = openmc.Material()
mat1.add_element('Be', 1)
mat1.set_density('atom/b-cm', 1)
my_materials=openmc.Materials([mat1])

surf1 = openmc.Sphere(r=610, boundary_type='vacuum')
surf1_region = -surf1
surf1_cell = openmc.Cell(region=surf1_region)

my_geometry = openmc.Geometry([surf1_cell])

my_settings = openmc.Settings()
my_settings.batches = 10
my_settings.particles = 500

model = openmc.model.Model(my_geometry, my_materials, my_settings)
model.export_to_model_xml()

openmc.lib.init()
nuc=openmc.lib.Nuclide('Be9')

MT =  c_int(16)
temperature =  c_double(294)
col=nuc.collapse_rate(MT, temperature,[0.,10.e6,20e6],[100.,200.,3.])

Environment

ubuntu 22.04, openmc-dev, python3.10.12

[paulromano]

@shimwell You were very close to having a working code -- the only change you need is:

nuc = openmc.lib.nuclides['Be9']

The lib.Nuclide class itself takes an integer index (if only it were type hinted, that would have been obvious 😉), where lib.nuclides is a mapping that gives a lib.Nuclide object given the name.

[paulromano]

Closing as this is not a bug; let me know if you run into further issues @shimwell