diff --git a/openmc/tallies.py b/openmc/tallies.py index 41d28f2a665..55f920b872b 100644 --- a/openmc/tallies.py +++ b/openmc/tallies.py @@ -136,7 +136,11 @@ def __eq__(self, other): return False if other.name != self.name: return False - if self.estimator is not None and other.estimator != self.estimator: + # estimators are automatically set during OpenMC initialization if this value is None, so it + # it not considered a requirement for equivalence if it is unset on either tally as it implies that + # the user is allowing OpenMC to apply the appropriate estimator. If the value is explicitly set + # on both tallies, then it must match to be considered equivalent. + if self.estimator is not None and other.estimator is not None and other.estimator != self.estimator: return False if other.filters != self.filters: return False