6                                          const sopt::mpi::Communicator &comm) {
 
    7   std::vector<t_int> send_sizes(recv_sizes.size(), 0);
 
    8   for (t_int i = 0; i < comm.size(); i++) {
 
   10       send_sizes = comm.gather<t_int>(recv_sizes[i], i);
 
   12       comm.gather<t_int>(recv_sizes[i], i);
 
std::vector< t_int > all_to_all_send_sizes(const std::vector< t_int > &recv_sizes, const sopt::mpi::Communicator &comm)