[mpich-discuss] mpi windows with groups mpich2

[Helen Kershaw]

Version 3.0.4.

Helen

On 4/28/14 10:38 AM, Rajeev Thakur wrote:
> 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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