Set parallel slices only for 3D metrics

src/mesh/parallel/fci.cxx

@@ -58,6 +58,7 @@ std::string parallel_slice_field_name(std::string field, int offset) {
   return direction + "_" + field + slice_suffix;
 };
 
+#if BOUT_USE_METRIC3D
 bool load_parallel_metric_component(std::string name, Field3D& component, int offset,
                                     bool doZero) {
   Mesh* mesh = component.getMesh();
@@ -101,8 +102,10 @@ bool load_parallel_metric_component(std::string name, Field3D& component, int of
   }
   return isValid;
 }
+#endif
 
-void load_parallel_metric_components(Coordinates* coords, int offset){
+void load_parallel_metric_components([[maybe_unused]] Coordinates* coords, [[maybe_unused]] int offset){
+#if BOUT_USE_METRIC3D
 #define LOAD_PAR(var, doZero) \
   load_parallel_metric_component(#var, coords->var, offset, doZero)
   LOAD_PAR(g11, false);
@@ -139,6 +142,7 @@ void load_parallel_metric_components(Coordinates* coords, int offset){
     BOUT_FOR(i, J.getRegion(rgn)) { pcom[i] = J[i]; }
   }
 #undef LOAD_PAR
+#endif
 }
 
 } // namespace