Merging ntuple on cluster

Hello, everybody,

today when I read the description of Example exMPI04 (example/Extended/ parallel/mpi/exMPI04/README), there is such a sentence:
The number of extra workers requested is set in G4MPImanager constructor in main(). While G4MPImanager can be created with any number of extra workers (< total number), the ntuple merging is at present supported only for one.

Does this means that I can only have one ntuple when calling MPI/G4MPI for computation on the cluster?
Now in my G4 program, there are dozens of ntuples, so do they not work?

Hello,

" the ntuple merging is at present supported only for one ." means that you can use just one extra worker for merging ntuples.

There is no limitation for number of ntuples; all ntuples should be merged on fly: the data buffers will be sent from the processing workers to the dedicated extra worker.

Best regards,