Fix distribcell hex lattice bug, see #411

src/output.F90

@@ -2398,10 +2398,24 @@ contains
                   end if
 
                   if (final >= lat % offset(map, k, l, m) + offset) then
-                    old_m = m
-                    old_l = l
-                    old_k = k
-                    cycle
+                    if (k == lat % n_rings .and. l == n_y .and. m == n_z) then
+                      ! This is last lattice cell, so target must be here
+                      lat_offset = lat % offset(map, k, l, m)
+                      offset = offset + lat_offset
+                      next_univ => universes(lat % universes(k, l, m))
+                      path = trim(path) // "(" // &
+                           trim(to_str(k - lat % n_rings)) // "," // &
+                           trim(to_str(l - lat % n_rings)) // "," // &
+                           trim(to_str(m)) // ")"
+                      call find_offset(map, goal, next_univ, final, offset, &
+                                       path)
+                      return
+                    else
+                      old_m = m
+                      old_l = l
+                      old_k = k
+                      cycle
+                    end if
                   else
                     ! Target is at this lattice position
                     lat_offset = lat % offset(map, old_k, old_l, old_m)

tests/test_filter_distribcell/case-4/geometry.xml

@@ -0,0 +1,23 @@
+<?xml version='1.0' encoding='utf-8'?>
+<geometry>
+    <cell fill="5" id="1" name="Cell 1" surfaces="1 -2 3 -4" universe="0" />
+<cell id="101" material="1" name="cell 2" surfaces="-5" universe="1" />
+<cell id="102" material="2" name="cell 3" surfaces="5" universe="1" />
+<cell id="500" material="2" name="cell 4" surfaces="" universe="3" />
+<hex_lattice id="5" n_rings="2">
+        <pitch>1.0</pitch>
+    <outer>3</outer>
+    <center>0.0 0.0</center>
+    <universes>
+ 1
+1 1
+ 1
+1 1
+ 1</universes>
+    </hex_lattice>
+<surface boundary="vacuum" coeffs="-3" id="1" name="left" type="x-plane" />
+<surface boundary="vacuum" coeffs="3" id="2" name="right" type="x-plane" />
+<surface boundary="vacuum" coeffs="-4" id="3" name="bottom" type="y-plane" />
+<surface boundary="vacuum" coeffs="4" id="4" name="top" type="y-plane" />
+<surface boundary="transmission" coeffs="0 0 0.4" id="5" type="z-cylinder" />
+</geometry>

tests/test_filter_distribcell/case-4/materials.xml

@@ -0,0 +1,18 @@
+<?xml version='1.0' encoding='utf-8'?>
+<materials>
+    <default_xs>71c</default_xs>
+<material id="1" name="fuel">
+        <density units="g/cc" value="4.5" />
+    <nuclide ao="1.0" name="U-235" />
+    </material>
+<material id="2" name="moderator">
+        <density units="g/cc" value="1.0" />
+    <nuclide ao="1.0" name="O-16" />
+    <nuclide ao="2.0" name="H-1" />
+    <sab name="HH2O" xs="71t" />
+    </material>
+<material id="3" name="iron">
+        <density units="g/cc" value="7.9" />
+    <nuclide ao="1.0" name="Fe-56" />
+    </material>
+</materials>

tests/test_filter_distribcell/case-4/results_true.dat

@@ -0,0 +1,17 @@
+k-combined:
+0.000000E+00 0.000000E+00
+tally 1:
+2.166056E-02
+4.691799E-04
+2.281665E-02
+5.205994E-04
+1.938848E-02
+3.759132E-04
+3.055366E-02
+9.335264E-04
+2.338209E-02
+5.467222E-04
+2.719869E-02
+7.397689E-04
+1.895698E-02
+3.593670E-04

tests/test_filter_distribcell/case-4/settings.xml

@@ -0,0 +1,13 @@
+<?xml version='1.0' encoding='utf-8'?>
+<settings>
+    <eigenvalue>
+        <particles>1000</particles>
+    <batches>1</batches>
+    <inactive>0</inactive>
+    </eigenvalue>
+<source>
+        <space type="box">
+            <parameters>-1 -1 -1 1 1 1</parameters>
+        </space>
+    </source>
+</settings>

tests/test_filter_distribcell/case-4/tallies.xml

@@ -0,0 +1,7 @@
+<?xml version='1.0' encoding='utf-8'?>
+<tallies>
+    <tally id="1">
+        <filter bins="101" type="distribcell" />
+    <scores>total</scores>
+    </tally>
+</tallies>

tests/test_filter_distribcell/test_filter_distribcell.py

@@ -18,10 +18,11 @@ class DistribcellTestHarness(TestHarness):
         """Run OpenMC with the appropriate arguments and check the outputs."""
         base_dir = os.getcwd()
         try:
-            dirs = ('case-1', '../case-2', '../case-3')
-            sps = ('statepoint.1.*', 'statepoint.1.*', 'statepoint.3.*')
-            tallies_out_present = (True, True, False)
-            hash_out = (False, False, True)
+            dirs = ('case-1', '../case-2', '../case-3', '../case-4')
+            sps = ('statepoint.1.*', 'statepoint.1.*', 'statepoint.3.*',
+                   'statepoint.1.*')
+            tallies_out_present = (True, True, False, True)
+            hash_out = (False, False, True, False)
             for i in range(len(dirs)):
                 os.chdir(dirs[i])
                 self._sp_name = sps[i]
@@ -41,10 +42,11 @@ class DistribcellTestHarness(TestHarness):
         """Update the results_true using the current version of OpenMC."""
         base_dir = os.getcwd()
         try:
-            dirs = ('case-1', '../case-2', '../case-3')
-            sps = ('statepoint.1.*', 'statepoint.1.*', 'statepoint.3.*')
-            tallies_out_present = (True, True, False)
-            hash_out = (False, False, True)
+            dirs = ('case-1', '../case-2', '../case-3', '../case-4')
+            sps = ('statepoint.1.*', 'statepoint.1.*', 'statepoint.3.*',
+                   'statepoint.1.*')
+            tallies_out_present = (True, True, False, True)
+            hash_out = (False, False, True, False)
             for i in range(len(dirs)):
                 os.chdir(dirs[i])
                 self._sp_name = sps[i]