ptr is uninitialized when sent by task 0, isn't it ? On Friday, January 22, 2016, Paweł Jarzębski <pj...@ippt.pan.pl> wrote:
> Hi, > > I wrote this code: > > program hello > implicit none > > include 'mpif.h' > integer :: rank, dest, source, tag, ierr, stat > integer :: n > integer :: taskinfo, ptr > > call MPI_INIT(ierr) > call MPI_COMM_RANK(MPI_COMM_WORLD, rank, ierr) > > if(rank.eq.0) then > write(*,*) 'Hello' > > n = 20 > dest = 1 > tag = 1 > taskinfo = n > call MPI_SEND(taskinfo, 1, MPI_INTEGER, dest, tag, > 1 MPI_COMM_WORLD, ierr) > > tag = tag + 1 > call MPI_SEND(ptr, 1, MPI_INTEGER, dest, tag, > 1 MPI_COMM_WORLD, ierr) > > else > source = 0 > tag = 1 > > ! n = 1 > call MPI_RECV(taskinfo, 1, MPI_INTEGER, source, tag, > 1 MPI_COMM_WORLD, stat, ierr) > > n = taskinfo > > tag = tag + 1 > > write(*,*) 'n1 ', n > write(*,*) 'taskinfo1 ', taskinfo > call MPI_RECV(ptr, 1, MPI_INTEGER, source, tag, > 1 MPI_COMM_WORLD, stat, ierr) > write(*,*) 'n2 ', n > write(*,*) 'taskinfo2 ', taskinfo > endif > > call MPI_FINALIZE(ierr) > end > > > I supposed that it should produce this: > Hello > n1 20 > taskinfo1 20 > n2 20 > taskinfo2 20 > > But in fact it produces this: > Hello > n1 20 > taskinfo1 20 > n2 2 > taskinfo2 20 > > It's strange to me that variable "n" is changed after call to MPI > subroutine, but I dont even put it in calls to MPI. > If I comment line 13 with " write(*,*) 'Hello' " everything is ok. If I > uncomment line 30 with "n = 1", everything is ok as well. > > Could anybody explain me what is happening? > > I tested it on: > 1) intel fortran compiler 14.0 and openmpi 1.6.5 > 1) intel fortran compiler 13.1.3 and openmpi 1.8.4 > > Best regards, > Pawel J. > > > > > _______________________________________________ > users mailing list > us...@open-mpi.org > Subscription: http://www.open-mpi.org/mailman/listinfo.cgi/users > Link to this post: > http://www.open-mpi.org/community/lists/users/2016/01/28334.php >
