Addressed comments by @samuelshaner

openmc/arithmetic.py

@@ -927,11 +927,6 @@ class AggregateFilter(object):
             if bin in other.bins:
                 return False
 
-        # None of the bins in the other filter should match in this filter
-        for bin in other.bins:
-            if bin in self.bins:
-                return False
-
         # If all conditional checks passed then filters are mergeable
         return True
 

openmc/filter.py

@@ -86,6 +86,8 @@ class Filter(object):
             else:
                 return False
         else:
+            # Compare largest/smallest energy bin edges in energy filters
+            # This logic is used when merging tallies with energy filters
             if 'energy' in self.type and 'energy' in other.type:
                 return self.bins[0] >= other.bins[-1]
             else:

openmc/geometry.py

@@ -253,7 +253,7 @@ class Geometry(object):
 
         """
 
-        if case_sensitive:
+        if not case_sensitive:
             name = name.lower()
 
         all_materials = self.get_all_materials()
@@ -293,7 +293,7 @@ class Geometry(object):
 
         """
 
-        if case_sensitive:
+        if not case_sensitive:
             name = name.lower()
 
         all_cells = self.get_all_cells()
@@ -333,7 +333,7 @@ class Geometry(object):
 
         """
 
-        if case_sensitive:
+        if not case_sensitive:
             name = name.lower()
 
         all_cells = self.get_all_cells()
@@ -373,7 +373,7 @@ class Geometry(object):
 
         """
 
-        if case_sensitive:
+        if not case_sensitive:
             name = name.lower()
 
         all_universes = self.get_all_universes()
@@ -413,7 +413,7 @@ class Geometry(object):
 
         """
 
-        if case_sensitive:
+        if not case_sensitive:
             name = name.lower()
 
         all_lattices = self.get_all_lattices()

openmc/mgxs/mgxs.py

@@ -241,8 +241,7 @@ class MGXS(object):
 
     @property
     def num_subdomains(self):
-        tally = list(self.tallies.values())[0]
-        domain_filter = tally.find_filter(self.domain_type)
+        domain_filter = self.xs_tally.find_filter(self.domain_type)
         return domain_filter.num_bins
 
     @property
@@ -877,14 +876,19 @@ class MGXS(object):
 
         # Clone this MGXS to initialize the subdomain-averaged version
         avg_xs = copy.deepcopy(self)
-        avg_xs._rxn_rate_tally = None
-        avg_xs._xs_tally = None
 
-        # Average each of the tallies across subdomains
-        for tally_type, tally in avg_xs.tallies.items():
-            tally_avg = tally.average(filter_type=self.domain_type,
-                                      filter_bins=subdomains)
-            avg_xs.tallies[tally_type] = tally_avg
+        if self.derived:
+            avg_xs._rxn_rate_tally = avg_xs.rxn_rate_tally.average(
+                filter_type=self.domain_type, filter_bins=subdomains)
+        else:
+            avg_xs._rxn_rate_tally = None
+            avg_xs._xs_tally = None
+
+            # Average each of the tallies across subdomains
+            for tally_type, tally in avg_xs.tallies.items():
+                tally_avg = tally.average(filter_type=self.domain_type,
+                                          filter_bins=subdomains)
+                avg_xs.tallies[tally_type] = tally_avg
 
         avg_xs._domain_type = 'avg({0})'.format(self.domain_type)
         avg_xs.sparse = self.sparse
@@ -1002,8 +1006,10 @@ class MGXS(object):
     def merge(self, other):
         """Merge another MGXS with this one
 
-        If results have been loaded from a statepoint, then MGXS are only
-        mergeable along one and only one of energy groups or nuclides.
+        MGXS are only mergeable if their energy groups and nuclides are either
+        identical or mutually exclusive. If results have been loaded from a
+        statepoint, then MGXS are only mergeable along one and only one of
+        energy groups or nuclides.
 
         Parameters
         ----------
@@ -1510,7 +1516,7 @@ class TotalXS(MGXS):
 
     @property
     def rxn_rate_tally(self):
-        if self._rxn_rate_tally is None:
+        if self._rxn_rate_tally is None :
             self._rxn_rate_tally = self.tallies['total']
             self._rxn_rate_tally.sparse = self.sparse
         return self._rxn_rate_tally

openmc/tallies.py

@@ -881,7 +881,7 @@ class Tally(object):
         # Differentiate Tally with a new auto-generated Tally ID
         merged_tally.id = None
 
-        # If the two tallies are equal, simpy return copy
+        # If the two tallies are equal, simply return copy
         if self == other:
             return merged_tally
 
@@ -936,7 +936,7 @@ class Tally(object):
         # If results have not been read, then return tally for input generation
         if self._results_read is None:
             return merged_tally
-        #Otherwise, this is a derived tally which needs merged results arrays
+        # Otherwise, this is a derived tally which needs merged results arrays
         else:
             self._derived = True