use better load balancer

apps/2021-tokamak/Tokamak.cpp

@@ -307,6 +307,9 @@ void tokamak( TokamakDomain         tokamakDomain,
    }
 
    SetupPrimitiveStorage setupStorage( meshInfo, uint_c( walberla::mpi::MPIManager::instance()->numProcesses() ) );
+
+   loadbalancing::roundRobinVolume(setupStorage);
+
    setupStorage.setMeshBoundaryFlagsOnBoundary( 1, 0, true );
 
    WALBERLA_LOG_INFO_ON_ROOT( "[progress] Setting up tokamak blending map ..." )