Addressing comments from @paulromano

docs/source/io_formats/statepoint.rst

@@ -80,8 +80,10 @@ The current version of the statepoint file format is 17.0.
              dimension.
            - **Unstructured Mesh Only:**
               - **volumes** (*double[]*) -- Volume of each mesh cell.
-              - **centroids** (*double[]*) -- Location of the mesh cell
-                centroids.
+              - **vertices** (*double[]*) -- Location of the mesh vertices.
+              - **connectivity** (*int[]*) -- Connectivity array for the mesh
+                cells.
+              - **element_types** (*int[]*) -- Mesh element types.
 
 **/tallies/filters/**
 

openmc/mesh.py

@@ -1477,7 +1477,7 @@ class UnstructuredMesh(MeshBase):
 
         .. versionadded:: 0.13
 
-    connectivity : np.ndarray (8, n_elements)
+    connectivity : np.ndarray (n_elements, 8)
         Connectivity of the elements
 
         .. versionadded:: 0.13
@@ -1633,6 +1633,17 @@ class UnstructuredMesh(MeshBase):
 
     def centroid(self, bin):
         """Return the vertex averaged centroid of an element
+
+        Parameters
+        ----------
+        bin : int
+            Bin ID for the returned centroid 
+        
+        Returns
+        -------
+        numpy.ndarray
+            x, y, z values of the element centroid
+
         """
         conn = self.connectivity[bin]
         coords = self.vertices[conn]
@@ -1749,11 +1760,7 @@ class UnstructuredMesh(MeshBase):
                     arr.SetTuple1(i, data.flat[i])
                 grid.GetCellData().AddArray(arr)
 
-        if vtk.VTK_MAJOR_VERSION == 5:
-            grid.update()
-            writer.SetInput(grid)
-        else:
-            writer.SetInputData(grid)
+        writer.SetInputData(grid)
 
         writer.Write()
 

src/mesh.cpp

@@ -256,7 +256,7 @@ void UnstructuredMesh::to_hdf5(hid_t group) const
     } else {
       num_elem_skipped++;
       xt::view(elem_types, i, xt::all()) = static_cast<int>(ElementType::UNSUPPORTED);
-      xt::view(connectivity, i, xt::all()) = xt::xarray<int>({-1, -1, -1, -1, -1, -1, -1, -1});
+      xt::view(connectivity, i, xt::all()) = -1;
     }
   }