added check to length of input args for IndependantOperator (#2799)

Co-authored-by: Paul Romano <paul.k.romano@gmail.com>

openmc/deplete/independent_operator.py

@@ -130,6 +130,14 @@ class IndependentOperator(OpenMCOperator):
         # Validate micro-xs parameters
         check_type('materials', materials, openmc.Materials)
         check_type('micros', micros, Iterable, MicroXS)
+        check_type('fluxes', fluxes, Iterable, float)
+
+        if not (len(fluxes) == len(micros) == len(materials)):
+            msg = (f'The length of fluxes ({len(fluxes)}) should be equal to '
+                   f'the length of micros ({len(micros)}) and the length of '
+                   f'materials ({len(materials)}).')
+            raise ValueError(msg)
+
         if keff is not None:
             check_type('keff', keff, tuple, float)
             keff = ufloat(*keff)

tests/unit_tests/test_deplete_independent_operator.py

@@ -4,8 +4,10 @@
 
 from pathlib import Path
 
-from openmc.deplete import IndependentOperator, MicroXS
+import pytest
+
 from openmc import Material, Materials
+from openmc.deplete import IndependentOperator, MicroXS
 
 CHAIN_PATH = Path(__file__).parents[1] / "chain_simple.xml"
 ONE_GROUP_XS = Path(__file__).parents[1] / "micro_xs_simple.csv"
@@ -36,3 +38,17 @@ def test_operator_init():
     fluxes = [1.0]
     micros = [micro_xs]
     IndependentOperator(materials, fluxes, micros, CHAIN_PATH)
+
+
+def test_error_handling():
+    micro_xs = MicroXS.from_csv(ONE_GROUP_XS)
+    fuel = Material(name="oxygen")
+    fuel.add_element("O", 2)
+    fuel.set_density("g/cc", 1)
+    fuel.depletable = True
+    fuel.volume = 1
+    materials = Materials([fuel])
+    fluxes = [1.0, 2.0]
+    micros = [micro_xs]
+    with pytest.raises(ValueError, match=r"The length of fluxes \(2\)"):
+        IndependentOperator(materials, fluxes, micros, CHAIN_PATH)