allow elements without points, closes #58

Author: cwsmith

src/MeshField_Element.hpp

@@ -455,11 +455,7 @@ evaluate(FieldElement &fes, Kokkos::View<Real **> localCoords,
            "to evaluate(...) were invalid\n");
     }
   }
-  if (localCoords.extent(0) < fes.numMeshEnts) {
-    fail("The size of dimension 0 of the local coordinates input array "
-         "must be at least %zu.\n",
-         fes.numMeshEnts);
-  }
+
   if (localCoords.extent(1) != fes.MeshEntDim + 1) {
     fail("Dimension 1 of the input array of local coordinates "
          "must have size = %zu.\n",
@@ -469,6 +465,15 @@ evaluate(FieldElement &fes, Kokkos::View<Real **> localCoords,
     fail("The input array of offsets must have size = %zu\n",
          fes.numMeshEnts + 1);
   }
+  LO numLocalCoords;
+  Kokkos::deep_copy(numLocalCoords,
+                    Kokkos::subview(offsets, offsets.size() - 1));
+  if (localCoords.extent(0) != numLocalCoords) {
+    fail("The size of dimension 0 of the local coordinates input array (%zu) "
+         "does not match the last entry of the offsets array (%zu).\n",
+         localCoords.extent(0), numLocalCoords);
+  }
+
   constexpr const auto numComponents = FieldElement::ValArray::size();
   const auto numPts = MeshFieldUtil::getLastValue(offsets);
   Kokkos::View<Real *[numComponents]> res("result", numPts);