Fix getNeighboringCellIndices

armi/reactor/grids/structuredgrid.py

@@ -368,7 +368,7 @@ def _meshBaseByBounds(index, bounds):
     @staticmethod
     def getNeighboringCellIndices(i, j=0, k=0):
         """Return the indices of the immediate neighbors of a mesh point in the plane."""
-        return ((i + 1, j, k), (1, j + 1, k), (i - 1, j, k), (i, j - 1, k))
+        return ((i + 1, j, k), (i, j + 1, k), (i - 1, j, k), (i, j - 1, k))
 
     @staticmethod
     def getAboveAndBelowCellIndices(indices):

armi/reactor/tests/test_reactors.py

@@ -1376,3 +1376,30 @@ def test_getNuclideCategoriesLogging(self):
 
         self.assertIn("Nuclide categorization", messages)
         self.assertIn("Structure", messages)
+
+
+class CartesianReactorNeighborTests(ReactorTests):
+    def setUp(self):
+        self.r = loadTestReactor(TEST_ROOT, inputFileName="zpprTest.yaml")[1]
+
+    def test_findNeighborsCartesian(self):
+        """Find neighbors of a given assembly in a Cartesian grid."""
+        loc = self.r.core.spatialGrid[1, 1, 0]
+        a = self.r.core.childrenByLocator[loc]
+        neighbs = self.r.core.findNeighbors(a)
+        locs = [tuple(a.spatialLocator.indices[:2]) for a in neighbs]
+        self.assertEqual(len(neighbs), 4)
+        self.assertIn((2, 1), locs)
+        self.assertIn((1, 2), locs)
+        self.assertIn((0, 1), locs)
+        self.assertIn((1, 0), locs)
+
+        # try with edge assembly
+        loc = self.r.core.spatialGrid[0, 0, 0]
+        a = self.r.core.childrenByLocator[loc]
+        neighbs = self.r.core.findNeighbors(a, showBlanks=False)
+        locs = [tuple(a.spatialLocator.indices[:2]) for a in neighbs]
+        self.assertEqual(len(neighbs), 2)
+        # in this case no locations that aren't actually in the core should be returned
+        self.assertIn((1, 0), locs)
+        self.assertIn((0, 1), locs)

doc/release/0.3.rst

@@ -12,7 +12,7 @@ What's new in ARMI?
 
 Bug Fixes
 ---------
-#. TBD
+#. ``StructuredGrid.getNeighboringCellIndices()`` was incorrectly implemented for the second neighbor. (`PR#1614 <https://github.com/terrapower/armi/pull/1614>`_)
 
 Changes that Affect Requirements
 --------------------------------