corrected bug in convection-diffusion when assigning a FieldVector<1> to a FieldVector<N>

src/amdis/assembler/ConvectionDiffusionOperator.hpp

@@ -104,7 +104,7 @@ namespace AMDiS
           jacobian.mv(shapeGradients[i][0], gradients[i]);
 
         const auto A = localFctA(local);
-        WorldVector b; b = localFctB(local);
+        WorldVector b = makeB(localFctB(local));
         const auto c = localFctC(local);
 
         IF_CONSTEXPR(conserving) {
@@ -194,6 +194,21 @@ namespace AMDiS
         [] (auto)    { return 0; });
     }
 
+    template <class T, int N>
+    static FieldVector<T,dow> makeB(FieldVector<T,N> const& b) { return b; }
+
+    template <class T, int N>
+    static FieldVector<T,dow> makeB(FieldVector<T,N>&& b) { return std::move(b); }
+
+    template <class T>
+    static FieldVector<T,dow> makeB(FieldVector<T,1> const& b) { return {T(b)}; }
+
+    template <class T>
+    static FieldVector<T,dow> makeB(FieldVector<T,1>&& b) { return {T(b)}; }
+
+    template <class T, std::enable_if_t<std::is_arithmetic<T>::value, int> = 0>
+    static FieldVector<T,dow> makeB(T b) { return {b}; }
+
   private:
     GridFctA gridFctA_;
     GridFctB gridFctB_;