On Thu, Feb 14, 2013 at 1:16 PM, Barry Smith <[email protected]> wrote:

Do we really ALWAYS want to call this version even if we are not monkeying with threads at ALL?

Thanks

Barry

ierr = MPI_Initialized(&flag);CHKERRQ(ierr); if (!flag) { if (PETSC_COMM_WORLD != MPI_COMM_NULL) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"You cannot set PETSC_COMM_WORLD if you have not initialized MPI first"); #if defined(PETSC_HAVE_MPI_INIT_THREAD) { PetscMPIInt provided; ierr = MPI_Init_thread(argc,args,MPI_THREAD_FUNNELED,&provided);CHKERRQ(ierr); } #else ierr = MPI_Init(argc,args);CHKERRQ(ierr);

The implementation of MPI_Init just probes around the environment and calls MPI_Init_thread. There is no performance advantage of MPI_THREAD_SINGLE over MPI_THREAD_FUNNELED so I think the code here is fine.