bugfix: there is an inconsistency between using global indices or local boundarypatch indices

this lead to computing the coordinate system for zero normals

dune/contact/assemblers/contactassembler.cc

@@ -42,33 +42,36 @@ void ContactAssembler<dim,field_type>::computeLocalCoordinateSystems(const Bound
 
     std::vector<CoordinateType> vertexNormals(contactBoundary.numVertices(), CoordinateType(0.0));
 
+    std::vector<int> globalToLocal;
+    contactBoundary.makeGlobalToLocal(globalToLocal);
+
     if (!obsDirections) {
-        contactBoundary.getNormals(vertexNormals);
+        std::vector<CoordinateType> globalNormals;
+        contactBoundary.getNormals(globalNormals);
+
+        // copy normals in local vector for the boundary nodes
+        for (size_t i=0; i<globalToLocal.size(); i++)
+            if (globalToLocal[i]>-1)
+                vertexNormals[globalToLocal[i]]=globalNormals[i];
     } else {
 
-        std::vector<int> globalToLocal;
-        contactBoundary.makeGlobalToLocal(globalToLocal);
 
         auto vIt    = contactBoundary.gridView().template begin<dim>();
         auto vEndIt = contactBoundary.gridView().template end<dim>();
 
         for (; vIt!=vEndIt; ++vIt) {
 
-            if (globalToLocal[indexSet.index(*vIt)]<0)
+            int localIndex = globalToLocal[indexSet.index(*vIt)];
+            if (localIndex<0)
                 continue;
 
             // Evaluate analytical normal field
-            vertexNormals[globalToLocal[indexSet.index(*vIt)]] = (*obsDirections)(vIt->geometry().corner(0));
+            vertexNormals[localIndex] = (*obsDirections)(vIt->geometry().corner(0));
+            // make sure it has length one
+            vertexNormals[localIndex] /= vertexNormals[localIndex].two_norm();
         }
     }
 
-    // ///////////////////////////////
-    //   Normalize vertex normals
-    // ////////////////////////////////
-
-    for (size_t i=0; i<vertexNormals.size(); i++)
-        vertexNormals[i] /= vertexNormals[i].two_norm();
-
     computeLocalCoordinateSystems(contactBoundary, coordSystems, vertexNormals);
 }