Merge branch 'volker/field' into uwe/field

src/field_operation.inl

@@ -191,24 +191,18 @@ field_operation2DiffType(
   static_assert(check_T_is_fielX_t<Field_T2_>(), "field2 must be from type 'Field_t' or 'const Field_t' or 'Field3D_t' or 'const Field3D_t'");
 
   if(std::holds_alternative<typeFloat>(field1)) {
-    typeFloat f1 = std::get<typeFloat>(field1);
     if(std::holds_alternative<typeFloat>(field2)) {
-      typeFloat f2 = std::get<typeFloat>(field2);
-      return f(f1, f2,  args...);
+      return f(std::get<typeFloat>(field1), std::get<typeFloat>(field2),  args...);
     } else if (std::holds_alternative<typeDouble>(field2)) {
-      typeDouble f2 = std::get<typeDouble>(field2);
-      return f(f1, f2,  args...);
+      return f(std::get<typeFloat>(field1), std::get<typeDouble>(field2),  args...);
     } else {
       throw std::runtime_error("Not supported Type of field2");
     }
   } else if(std::holds_alternative<typeDouble>(field1)) {
-    typeDouble f1 = std::get<typeDouble>(field1);
     if(std::holds_alternative<typeFloat>(field2)) {
-      typeFloat f2 = std::get<typeFloat>(field2);
-      return f(f1, f2,  args...);
+      return f(std::get<typeDouble>(field1), std::get<typeFloat>(field2),  args...);
     } else if (std::holds_alternative<typeDouble>(field2)) {
-      typeDouble f2 = std::get<typeDouble>(field2);
-      return f(f1, f2,  args...);
+      return f(std::get<typeDouble>(field1), std::get<typeDouble>(field2),  args...);
     } else {
       throw std::runtime_error("Not supported Type of field2");
     }