simgrid::config::declare_flag<std::string>("smpi/alltoallv", "Which collective to use for alltoallv", "");
simgrid::config::declare_flag<std::string>("smpi/bcast", "Which collective to use for bcast", "");
simgrid::config::declare_flag<std::string>("smpi/reduce", "Which collective to use for reduce", "");
simgrid::config::declare_flag<std::string>("smpi/alltoallv", "Which collective to use for alltoallv", "");
simgrid::config::declare_flag<std::string>("smpi/bcast", "Which collective to use for bcast", "");
simgrid::config::declare_flag<std::string>("smpi/reduce", "Which collective to use for reduce", "");