Hello everyone,
I'm trying to implement some functions in my code using parallel writing. Each processor has an array, say q, whose length is single_no(could be zero on some processors). I want to write q down to a common file, but the elements of q would be scattered to their locations in this file. The locations of the elements are described by a map. I wrote my testing code according to an example in a MPI-2 tutorial which can be found here: www.npaci.edu/ahm2002/ahm_ppt/Parallel_IO_MPI_2.ppt. This way of writing is called "Accessing Irregularly Distributed Arrays" in this tutorial and the example is given in page 42. I tested my code with mvapich and got the result as expected. But when I tested it with openmpi, it didn't work. I tried the version 1.2.8 and 1.4 and both didn't work. I tried two clusters. Both of them are intel chips (woodcrest and nehalem), DDR infiniband with Linux system. I got some error message like +++++++++++++++++++++++++++++++++++++++++++++++++++ [n0883:08251] *** Process received signal *** [n0883:08249] *** Process received signal *** [n0883:08249] Signal: Segmentation fault (11) [n0883:08249] Signal code: Address not mapped (1) [n0883:08249] Failing at address: (nil) [n0883:08251] Signal: Segmentation fault (11) [n0883:08251] Signal code: Address not mapped (1) [n0883:08251] Failing at address: (nil) [n0883:08248] *** Process received signal *** [n0883:08250] *** Process received signal *** [n0883:08248] Signal: Segmentation fault (11) [n0883:08248] Signal code: Address not mapped (1) [n0883:08248] Failing at address: (nil) [n0883:08250] Signal: Segmentation fault (11) [n0883:08250] Signal code: Address not mapped (1) [n0883:08250] Failing at address: (nil) [n0883:08251] [ 0] /lib64/libpthread.so.0 [0x2b4f0a2f0d60] +++++++++++++++++++++++++++++++++++++++++++++++++++ My testing code is here: =========================================================================================================== program test_MPI_write_adv2 !-- Template for any mpi program implicit none !--Include the mpi header file include 'mpif.h' ! --> Required statement !--Declare all variables and arrays. integer :: fh, ierr, myid, numprocs, itag, etype, filetype, info integer :: status(MPI_STATUS_SIZE) integer :: irc, ip integer(kind=mpi_offset_kind) :: offset, disp integer :: i, j, k integer :: num character(len=64) :: filename real(8), pointer :: q(:), temp(:) integer, pointer :: map(:) integer :: single_no, count !--Initialize MPI call MPI_INIT( ierr ) ! --> Required statement !--Who am I? --- get my rank=myid call MPI_COMM_RANK( MPI_COMM_WORLD, myid, ierr ) !--How many processes in the global group? call MPI_COMM_SIZE( MPI_COMM_WORLD, numprocs, ierr ) if ( myid == 0 ) then single_no = 4 elseif ( myid == 1 ) then single_no = 2 elseif ( myid == 2 ) then single_no = 2 elseif ( myid == 3 ) then single_no = 3 else single_no = 0 end if if (single_no .gt. 0) allocate(map(single_no)) if ( myid == 0 ) then map = (/ 0, 2, 5, 6 /) elseif ( myid == 1 ) then map = (/ 1, 4 /) elseif ( myid == 2 ) then map = (/ 3, 9 /) elseif ( myid == 3 ) then map = (/ 7, 8, 10 /) end if if (single_no .gt. 0) allocate(q(single_no)) if (single_no .gt. 0) then do i = 1,single_no q(i) = dble(myid+1)*100.0d0 + dble(map(i)+1) end do end if if (single_no .gt. 0) map = map + 1 if ( myid == 0 ) then count = 1 else count = 0 end if if (count .gt. 0) then allocate(temp(count)) temp(1) = 2122010.0d0 end if write(filename,'(a)') 'test_write.bin' call MPI_FILE_OPEN(MPI_COMM_WORLD, filename, MPI_MODE_RDWR+MPI_MODE_CREATE, MPI_INFO_NULL, fh, ierr) call MPI_FILE_WRITE(FH, temp, COUNT, MPI_REAL8, STATUS, IERR) call MPI_TYPE_CREATE_INDEXED_BLOCK(single_no, 1, map, MPI_DOUBLE_PRECISION, filetype, ierr) call MPI_TYPE_COMMIT(filetype, ierr) disp = 0 call MPI_FILE_SET_VIEW(fh, disp, MPI_DOUBLE_PRECISION, filetype, 'native', MPI_INFO_NULL, ierr) call MPI_FILE_WRITE_ALL(fh, q, single_no, MPI_DOUBLE_PRECISION, status, ierr) call MPI_FILE_CLOSE(fh, ierr) if (single_no .gt. 0) deallocate(map) if (single_no .gt. 0) deallocate(q) if (count .gt. 0) deallocate(temp) !--Finilize MPI call MPI_FINALIZE(irc) ! ---> Required statement stop end program test_MPI_write_adv2 =========================================================================================================== The expected result is (should be in binary but the values are as follows) : 2122010.00000000 101.000000000000 202.000000000000 103.000000000000 304.000000000000 205.000000000000 106.000000000000 107.000000000000 408.000000000000 409.000000000000 310.000000000000 411.000000000000 Can anyone help me on this problem? Thanks a lot, Kan