[mpich-discuss] mpi windows with groups mpich2

[Rajeev Thakur]

The program runs fine on my Mac laptop. Which version of MPICH are you using?

Rajeev

On Apr 28, 2014, at 10:41 AM, Helen Kershaw <hkershaw at ucar.edu> wrote:

> Hi,
> 
> I'm trying to use MPI one-sided communication with sub-communicators.
> I've put my test code at the end of the email.  It runs on 8 processors, creates two communicators, makes a window on the communicators, then tries to do some one-sided communication.
> 
> I can use groups OR windows without a problem, but when I use them
> together (in the test code) I get a coredump from the first 4 tasks.  I
> think the one-sided communication may be using the local rank in the sub-communicator (mpi_comm_grid) as if it is the global rank in mpi_comm_world.
> 
> I can run the test code ok using open-mpi, but not mpich2.  I might be
> missing something obvious.
> 
> Thanks for your help,
> Helen
> 
> -----
> program test_group_win
> 
> use mpi
> 
> implicit none
> 
> ! mpi
> integer            :: rank, size, ierr, status(mpi_status_size)
> ! groups
> integer, parameter :: group_size = 4
> integer            :: group_members(group_size)
> integer            :: group_all ! mpi_comm_world group
> integer            :: subgroup
> integer            :: mpi_comm_grid
> integer            :: local_rank ! rank within subgroup
> 
> 
> ! window
> integer                        :: win
> integer                        ::bytesize !> size in bytes of each
> element in the window
> integer(KIND=MPI_ADDRESS_KIND) :: window_size
> pointer(aa, duplicate)
> real                           :: duplicate(*)
> integer(KIND=MPI_ADDRESS_KIND) :: target_disp !> displacement in window
> integer                        :: owner
> real                           :: result
> 
> call mpi_init(ierr)
> call mpi_comm_size(mpi_comm_world, size, ierr)
> call mpi_comm_rank(mpi_comm_world, rank, ierr)
> 
> ! create groups
> call mpi_comm_group(mpi_comm_world, group_all, ierr)
> 
> if (rank < 4 ) then
>   group_members = (/0,1,2,3/)
> else
>   group_members = (/4,5,6,7/)
> endif
> 
> call mpi_group_incl(group_all, group_size, group_members, subgroup, ierr)
> call mpi_comm_create(mpi_comm_world, subgroup, mpi_comm_grid, ierr)
> call mpi_comm_rank(mpi_comm_grid, local_rank, ierr) ! rank within group
> 
> ! create window
> call mpi_type_size(mpi_real, bytesize, ierr)
> window_size = bytesize ! one element in the window
> aa = malloc(1)
> call MPI_ALLOC_MEM(window_size, mpi_info_null, aa, ierr)
> 
> duplicate(1) = rank
> 
> call mpi_win_create(duplicate,  window_size, bytesize, MPI_INFO_NULL,
> mpi_comm_grid, win, ierr)
> 
> ! grabbing data from rank above
> if (rank < 3 ) then
>   owner = rank + 1
> elseif (rank < 7) then
>   owner = rank + 1 - 4
> else
>   owner = 0
> endif
> 
> print*, 'rank owner', rank, owner
> 
> target_disp = 0
> 
> call mpi_win_lock(MPI_LOCK_SHARED, owner, 0,  win, ierr)
> call mpi_get(result, 1, mpi_real, owner, target_disp, 1, mpi_real, win,
> ierr)
> call mpi_win_unlock(owner, win, ierr)
> 
> print*, 'rank, result ', rank, result
> 
> ! free window
> call mpi_win_free(win, ierr)
> call mpi_free_mem(duplicate, ierr)
> 
> call mpi_finalize(ierr)
> 
> end program test_group_win
> ----
> 
> 
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