Comment about a problematic case

src/hierarchical.cpp

@@ -38,7 +38,8 @@ void create_communicators_hierarch( MPI_Comm& COMM_FOREMEN, MPI_Comm& COMM_TEAM
     MPI_Comm_split( MPI_COMM_WORLD, color_foreman, rank, &COMM_FOREMEN );
 
     /* Create the communicator between the workers and their foreman */
-
+    /* There is one problematic case here: when the last foreman ends up alone in its communicator */
+    
     int color_team;
     if( ROOT == rank ) {
         color_team = 0;