Distribtued density regression test.

Author: nuclearkevin

src/geometry_aux.cpp

@@ -201,7 +201,8 @@ void finalize_cell_densities()
     // Convert to density multipliers.
     if (c->xml_set_density_) {
       for (int32_t instance = 0; instance < c->rho_mult_.size(); ++instance) {
-        c->rho_mult_[instance] /= model::materials[c->material(instance)]->density_gpcc();
+        c->rho_mult_[instance] /=
+          model::materials[c->material(instance)]->density_gpcc();
       }
     }
   }

tests/regression_tests/lattice_distribrho/__init__.py

@@ -0,0 +1,40 @@
+<?xml version='1.0' encoding='utf-8'?>
+<model>
+  <materials>
+    <material id="1" name="UO2" depletable="true">
+      <density value="10.0" units="g/cm3"/>
+      <nuclide name="U235" ao="1.0"/>
+      <nuclide name="O16" ao="2.0"/>
+    </material>
+    <material id="2" name="light water">
+      <density value="1.0" units="g/cm3"/>
+      <nuclide name="H1" ao="2.0"/>
+      <nuclide name="O16" ao="1.0"/>
+      <sab name="c_H_in_H2O"/>
+    </material>
+  </materials>
+  <geometry>
+    <cell id="1" material="1" region="-1" density="10.0 20.0 10.0 20.0" universe="1"/>
+    <cell id="2" material="2" region="1" universe="1"/>
+    <cell id="3" fill="2" region="2 -3 4 -5" universe="3"/>
+    <lattice id="2">
+      <pitch>1.0 1.0</pitch>
+      <dimension>2 2</dimension>
+      <lower_left>-1.0 -1.0</lower_left>
+      <universes>
+1 1 
+1 1 </universes>
+    </lattice>
+    <surface id="1" type="z-cylinder" coeffs="0.0 0.0 0.4"/>
+    <surface id="2" name="minimum x" type="x-plane" boundary="reflective" coeffs="-1.0"/>
+    <surface id="3" name="maximum x" type="x-plane" boundary="reflective" coeffs="1.0"/>
+    <surface id="4" name="minimum y" type="y-plane" boundary="reflective" coeffs="-1.0"/>
+    <surface id="5" name="maximum y" type="y-plane" boundary="reflective" coeffs="1.0"/>
+  </geometry>
+  <settings>
+    <run_mode>eigenvalue</run_mode>
+    <particles>1000</particles>
+    <batches>10</batches>
+    <inactive>5</inactive>
+  </settings>
+  </model>

tests/regression_tests/lattice_distribrho/inputs_true.dat

@@ -0,0 +1,2 @@
+k-combined:
+1.904471E+00 5.255549E-03

tests/regression_tests/lattice_distribrho/results_true.dat

@@ -0,0 +1,45 @@
+import openmc
+import pytest
+
+from tests.testing_harness import PyAPITestHarness
+
+@pytest.fixture
+def model():
+    model = openmc.model.Model()
+
+    uo2 = openmc.Material(name='UO2')
+    uo2.set_density('g/cm3', 10.0)
+    uo2.add_nuclide('U235', 1.0)
+    uo2.add_nuclide('O16', 2.0)
+    water = openmc.Material(name='light water')
+    water.add_nuclide('H1', 2.0)
+    water.add_nuclide('O16', 1.0)
+    water.set_density('g/cm3', 1.0)
+    water.add_s_alpha_beta('c_H_in_H2O')
+    model.materials.extend([uo2, water])
+
+    cyl = openmc.ZCylinder(r=0.4)
+    pin = openmc.model.pin([cyl], [uo2, water])
+    d = 1.0
+
+    lattice = openmc.RectLattice()
+    lattice.lower_left = (-d, -d)
+    lattice.pitch = (d, d)
+    lattice.universes = [[pin, pin],
+                         [pin, pin]]
+    box = openmc.model.RectangularPrism(2.0 * d, 2.0 * d, origin=(0.0,0.0), boundary_type='reflective')
+
+    pin.cells[1].density = [10.0, 20.0, 10.0, 20.0]
+
+    model.geometry = openmc.Geometry([openmc.Cell(fill=lattice, region = -box)])
+    model.geometry.merge_surfaces = True
+
+    model.settings.batches = 10
+    model.settings.inactive = 5
+    model.settings.particles = 1000
+
+    return model
+
+def test_lattice_checkerboard(model):
+    harness = PyAPITestHarness('statepoint.10.h5', model)
+    harness.main()