Hi Jordy, I don't think this part caused the problem. For fortran, it doesn't matter if the pointer is NULL as long as the count requested from the processor is 0. Actually I tested the code and it passed this part without problem. I believe it aborted at MPI_FILE_SET_VIEW part.
Just curious, how does C handle the case that we need to collect data in array q but only part of the processors has q with a length greater than 0? Thanks for your reply, Kan On Wed, Feb 24, 2010 at 2:29 AM, jody <jody....@gmail.com> wrote: > Hi > I know nearly nothing about fortran > but it looks to me as the pointer 'temp' in > > > call MPI_FILE_WRITE(FH, temp, COUNT, MPI_REAL8, STATUS, IERR) > > is not defined (or perhaps NULL?) for all processors except processor 0 : > > > 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 > > In C/C++ something like this would almost certainly lead to a crash, > but i don't know if this would be the case in Fortran... > jody > > > On Wed, Feb 24, 2010 at 4:38 AM, w k <thuw...@gmail.com> wrote: > > 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 > > > > > > > > > > _______________________________________________ > > users mailing list > > us...@open-mpi.org > > http://www.open-mpi.org/mailman/listinfo.cgi/users > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/users >
