Merge 4274aec into 571e4f5

armi/nuclearDataIO/cccc/nhflux.py

@@ -251,8 +251,11 @@ def readWrite(self):
         # Read the hex ordering map between DIF3D nodal and DIF3D GEODST. Also read index
         # pointers to incoming partial currents on outer reactor surface (these don't
         # belong to any assembly). Incoming partial currents are non-zero due to flux
-        # extrapolation
-        self._rwGeodstCoordMap2D()
+        # extrapolation. This record is only required when nSurf is greater than 1. It
+        # is equal to 1 for VARSRC files, which are a subset of NHFLUX files; VARSRC files
+        # do not have a 2D record (or 4D or 5D records).
+        if self._metadata["nSurf"] > 1:
+            self._rwGeodstCoordMap2D()
 
         # Number of energy groups
         ng = self._metadata["ngroup"]
@@ -318,7 +321,7 @@ def readWrite(self):
                         self._data.fluxMomentsAll[:, z, :, gEff]
                     )
 
-                # Process currents
+                # Process currents, but only if iwnhfl is not equal to 1
                 if self._metadata["iwnhfl"] != 1:
                     # Loop through axial nodes
                     for z in range(nz):

armi/nuclearDataIO/cccc/tests/test_nhflux.py

@@ -191,3 +191,57 @@ def test_write(self):
                 actualData = f2.read()
             for expected, actual in zip(expectedData, actualData):
                 self.assertEqual(expected, actual)
+
+
+class TestNhfluxVariantVarsrc(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        """
+        Load NHFLUX data from binary file. This file was produced using VARIANT v11.0
+        and is identical to the file used in TestNhfluxVariant.
+        """
+        cls.nhf = nhflux.NhfluxStreamVariant.readBinary(SIMPLE_HEXZ_NHFLUX_VARIANT)
+
+        # Make the data structure match the format for VARSRC
+        cls.nhf.metadata["nSurf"] = 1
+        cls.nhf.metadata["iwnhfl"] = 1
+        cls.emptyDatasets = [
+            "incomingPointersToAllAssemblies",
+            "externalCurrentPointers",
+            "geodstCoordMap",
+            "outgoingPCSymSecPointers",
+            "ingoingPCSymSecPointers",
+            "partialCurrentsHexAll",
+            "partialCurrentsHex_extAll",
+            "partialCurrentsZAll",
+        ]
+        for zeroDataset in cls.emptyDatasets:
+            setattr(cls.nhf, zeroDataset, np.array([]))
+
+    def test_writeRead(self):
+        """
+        Write out the modified data structure to file. Then, we read it back in and make
+        sure it matches the data currently in memory.
+        """
+        filename = "VARSRC"
+        with TemporaryDirectoryChanger():
+            nhflux.NhfluxStreamVariant.writeBinary(self.nhf, filename)
+            writtenVarsrc = nhflux.NhfluxStreamVariant.readBinary(filename)
+
+        # Make sure the metadata matches
+        self.assertEqual(len(writtenVarsrc.metadata), len(self.nhf.metadata))
+        for key in writtenVarsrc.metadata:
+            self.assertEqual(writtenVarsrc.metadata[key], self.nhf.metadata[key])
+
+        # Make sure that the flux moments match identically
+        self.assertTrue(
+            np.isclose(
+                writtenVarsrc.fluxMoments, self.nhf.fluxMoments, rtol=0.0, atol=0.0
+            ).all()
+        )
+
+        # Make sure all other datasets are empty, since the reader should not be trying
+        # to populate them.
+        for zeroDataset in self.emptyDatasets:
+            dataset = getattr(self.nhf, zeroDataset)
+            self.assertEqual(dataset.shape, (0,))