Make openmc an optional dependency #24

libra_toolbox/neutronics/neutron_source.py

@@ -5,11 +5,9 @@
 from collections.abc import Iterable
 import pandas as pd
 import numpy as np
-import h5py
-import openmc
 
 
-def A325_generator_diamond(center=(0, 0, 0), reference_uvw=(0, 0, 1)) -> Iterable[openmc.IndependentSource]:
+def A325_generator_diamond(center=(0, 0, 0), reference_uvw=(0, 0, 1)) -> Iterable:
     """
     Builds the MIT-VaultLab A-325 neutron generator in OpenMC
     with data tabulated from John Ball and Shon Mackie characterization
@@ -28,15 +26,20 @@ def A325_generator_diamond(center=(0, 0, 0), reference_uvw=(0, 0, 1)) -> Iterabl
 
     Returns
     -------
-        list of openmc neutron sources with angular and energy distribution 
+        list of openmc neutron sources with angular and energy distribution
         and total strength of 1
     """
+    try:
+        import h5py
+        import openmc
+    except ModuleNotFoundError:
+        raise ModuleNotFoundError("openmc and h5py are required")
 
     filename = "A325_generator_diamond.h5"
     filename = str(Path(__file__).parent) / Path(filename)
 
     with h5py.File(filename, "r") as source:
-        df = pd.DataFrame(source["values/table"][()]).drop(columns='index')
+        df = pd.DataFrame(source["values/table"][()]).drop(columns="index")
         # energy values
         energies = np.array(df["Energy (MeV)"]) * 1e6
         # angle column names