# Error running coarray **URL:** \ **Category:** Help\ **Created:** [June 20, 2022, 11:03am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808 "2022-06-20T11:03:51Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 20, 2022, 11:03am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/1 "2022-06-20T11:03:52Z")
Hi all, I’m triing to run an example code with coarray with oneapi intel compiler on a shared memory system. When I run the code of example on a single image all seems to go ok, but if I set -coarray=shared and -coarray-num-images=6 (or any other number) I’ve the following error: ```auto =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = RANK 8 PID 953 RUNNING AT 41ca5757f459 = KILLED BY SIGNAL: 11 (Segmentation fault) =================================================================================== =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = RANK 9 PID 954 RUNNING AT 41ca5757f459 = KILLED BY SIGNAL: 11 (Segmentation fault) =================================================================================== =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = RANK 10 PID 955 RUNNING AT 41ca5757f459 = KILLED BY SIGNAL: 11 (Segmentation fault) =================================================================================== =================================================================================== = BAD TERMINATION OF ONE OF YOUR APPLICATION PROCESSES = RANK 11 PID 956 RUNNING AT 41ca5757f459 = KILLED BY SIGNAL: 11 (Segmentation fault) =================================================================================== ``` This is not due to error proble, the code print only a welcome messages from any images! I compile the code with the following command: ```auto ifort -O3 -coarray=shared -coarray-num-images=6 hello.f90 -o hello ``` The compilation seems ok, no error after the command, but if I run it with ./hello I have the previows one error! anyone have any Idea? Thank you in advance ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 21, 2022, 4:57am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/2 "2022-06-21T04:57:13Z")
It’s impossible to help without more info. Please post the exact code you’re compiling – it sounds like it is just a few lines. What platform? What version of the compiler? ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 21, 2022, 7:36am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/3 "2022-06-21T07:36:44Z")
Hello and thanks for your help, my example code is: ```auto program main implicit none print *,"debug 1" ! 1st statement of program write (*,*) "Hello from image", this_image(), "of", num_images() sync all print *,"debug 2" ! 1st statement following first coarray-esk statement. write (*,*) "Goodbye from image", this_image(), "of", num_images() end program main ``` the version of the compiler is: ```auto root@8c6937a9880a:/home/data# root@8c6937a9880a:/home/data# ifort --version ifort (IFORT) 2021.6.0 20220226 Copyright (C) 1985-2022 Intel Corporation. All rights reserved. ``` and the platform is Linux Ubuntu. I think the problem is in environment configuration, but I don’t understand where I’m wrong. Thanks, best regards ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 21, 2022, 1:55pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/4 "2022-06-21T13:55:29Z")
> [@sverdrup](#): > > I think the problem is in environment configuration, […] I would agree. This works fine for me (same compiler, Fedora 35). Did you install the Intel MPI library from the OneAPI HPC toolkit? I would have expected the compiler to complain about missing libraries if you hadn’t, but perhaps not. Also, have you sourced the `setvars.sh` script from the oneapi installation directory? ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 21, 2022, 2:40pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/5 "2022-06-21T14:40:20Z")
Yes I’ve installed the MPI library from the oneAPI HPC toolkit, and yes I’ve runned the setvars.sh script fro the oneapi installation directory… I’ve no idea to solve this problem, any idea is welcome. Thanks ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 21, 2022, 2:47pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/6 "2022-06-21T14:47:43Z")
Bummer. Since the compiler works with a single image, I’m afraid I’m out of ideas. If you haven’t already, you should consider posing your problem on Intel’s Fortran forum. ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 21, 2022, 3:03pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/7 "2022-06-21T15:03:12Z")
Actually one more thought. Are you able to run an MPI program using Intel’s MPI library? An MPI version of your hello.f90 program: ```fortran program main use mpi implicit none integer :: nproc, this_rank, ierr call MPI_Init(ierr) call MPI_Comm_size(MPI_COMM_WORLD, nproc, ierr) call MPI_Comm_rank(MPI_COMM_WORLD, this_rank, ierr) write (*,*) "Hello from image", this_rank, "of", nproc call MPI_Barrier(MPI_COMM_WORLD, ierr) write (*,*) "Goodbye from image", this_rank, "of", nproc call MPI_Finalize(ierr) end program main ``` Then ```nohighlight mpifc hello-mpi.f90 mpiexec -np 3 ./a.out ``` Strangely, I couldn’t get the `mpi_f08` module version to work; the compiler complained about “undefined reference to `mpi\_f08\_compile\_constants\_MP\_mpi\_comm\_world\_'”. But I only ever use Intel’s MPI when I’m experimenting with coarrays and the Intel compiler. ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 23, 2022, 6:50am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/8 "2022-06-23T06:50:10Z")
Ok, I managed to reinstall and compile the program, now I can compile and run the Hello example. Now I’ve a new mistacke on my code, when I run the code after few seconds the program freeze, I’ve added some flag in the compilation to debug the code (-g -traceback). The problem seems to be in a subrutine which uses coarrays. ```auto subroutine write_bat(medb,outf) use iso_fortran_env, only: stdout => output_unit, & stderr => error_unit class (Sbathy),intent(in)::medb character(len=*), intent(in)::outf character*40,parameter :: odir="/home/data/bathy_img/" character*12, parameter ::ofile='pippo1.bat' real, allocatable, dimension(:,:),codimension[:] :: bt integer ::i,j,ic, nlat,nlon integer, dimension(4)::ib print *, this_image(), 'write_bat test -----------------------' nlat=medb%gmed%nlat nlon=medb%gmed%nlon ib= medb%get_inner() print*, this_image(), 'bbox= ',ib write(*,'(a10,4(f8.4,2x))') 'bbox exp= ',medb%gmed%lon(ib(1)),medb%gmed%lon(ib(2)),& medb%gmed%lat(ib(3)),medb%gmed%lat(ib(4)) !if (this_image()==2) then !print*,this_image(), medb%gemo%box%p0%plat, medb%gemo%box%p1%plat ,medb%gmed%box%p0%plat !end if allocate(bt(nlon,nlat)[*]) !local bathymetry bt=medb%gmed%z(1:nlon,1:nlat) sync all do ic=2,num_images() if (this_image().eq.ic) then do j=ib(3),ib(4) do i=ib(1),ib(2) bt(i,j)[1]=bt(i,j) end do end do end if sync all end do open(stdout,file=outf,status='unknown',access='stream') if(this_image()==1) write(stdout) bt(:,:) close(stdout) !open(stdout,file=trim(odir)//trim(ofile),status='unknown',access='stream') !if (this_image()==2) write(stdout) medb%gmed%z !close(stdout) end subroutine write_bat ``` I compile the code with: ```auto ifort -O3 -traceback -g -coarray=shared -coarray-num-images=6 mod_bathy_field.f90 bathy.f90 `nf-config --fflags --flibs` -o pippon ``` and run it with: ./pippon Anyone have some idea on what is the cause of the problem? Can I provide more information to help me to solve it? best regards ---
**Author:** ![Sideboard](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/sideboard/32/779_2.png) [@Sideboard](https://fortran-lang.discourse.group/u/Sideboard)\ **Post date:** [June 23, 2022, 8:14am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/9 "2022-06-23T08:14:29Z")
You could add write/print statements inside and after the loop to check where it’s stuck. (Or use a debugger.) One line that stands out to me is: ```auto open(stdout,file=outf,status='unknown',access='stream') ``` I thought it was not allowed to open an already open unit, especially stdout. ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 23, 2022, 8:32am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/10 "2022-06-23T08:32:38Z")
Hello Sideboard and thank you for your help. Before the loop there is a print statements, but when I run the code seems to stuck at the beginning of the subroutine. This subrutine is called from the main, before the call there is a sync all, and if I use a debugger flag (-g) the problem seems the sync all, I’ve commented it, and after that the debugger point to the subrutine at this specific line: ```auto allocate(bt(nlon,nlat)[*]) ``` but the print statement not was printed before the incriminated line. ---
**Author:** ![Sideboard](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/sideboard/32/779_2.png) [@Sideboard](https://fortran-lang.discourse.group/u/Sideboard)\ **Post date:** [June 23, 2022, 9:14am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/11 "2022-06-23T09:14:16Z")
> [@sverdrup](#): > > but the print statement not was printed before the incriminated line. Note that output is buffered. To check that, you could use `flush(stdout)` directly after the print/write. ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 23, 2022, 9:59am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/12 "2022-06-23T09:59:35Z")
At the beginning of the subrutine I’ve put a print, but there is no print on screen, I think the subroutine don’t start. I’m very new user in fortran, maybe I’ve used it in the past, but now I’m very rusty and many things have changed. There is a way to test the problem writing a simple test code or something like that? thank you, best regards ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 24, 2022, 3:50pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/13 "2022-06-24T15:50:32Z")
Glad you were to sort out your initial problem with your hello program. Is your write\_bat subroutine a module procedure (i.e., defined in a module) and your main program uses that module? Or have you written an explicit interface block for it in the main program? Because of its `class(Sbathy)` dummy argument you can’t call it with an implicit interface, as in old F77 style. ---
**Author:** ![sverdrup](https://avatars.discourse-cdn.com/v4/letter/s/58956e/32.png) [@sverdrup](https://fortran-lang.discourse.group/u/sverdrup)\ **Post date:** [June 25, 2022, 4:47am UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/14 "2022-06-25T04:47:43Z")
I attach the code here. I hope this clarify all your questions. Thank’s for your help, best regards [mod\_bathy\_field.f90](https://fortran-lang.discourse.group/uploads/short-url/i8WkeldHgBUDLGzcUxDwRpAgrd1.f90) (10.8 KB) [bathy.f90](https://fortran-lang.discourse.group/uploads/short-url/lUvfDsAYxS8SNSP6wMh7NBTCNKh.f90) (1.8 KB) ---
**Author:** ![nncarlson](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/nncarlson/32/1175_2.png) [@nncarlson](https://fortran-lang.discourse.group/u/nncarlson)\ **Post date:** [June 26, 2022, 10:52pm UTC](https://fortran-lang.discourse.group/t/error-running-coarray/3808/15 "2022-06-26T22:52:01Z")
You indicate that the problem appears to be happening at about the call to `write_bat` or early inside. I don’t see anything obviously wrong that would account for the hang. So you really just need to pin down the line where things go wrong as @Sideboard suggested. Print statements are a low tech debugging approach, but can be very effective. Frankly it’s what I do 99% of the time. Add the line ```fortran print *, "FOO", this_image() ``` immediately before the call to `write_bat` (and after the `sync all`), and add the line ```fortran print *, "BAR", this_image() ``` as the _very first_ executable statement in `write_bat`. Do all the images print “FOO” but only some, or none, print “BAR”? If so then something is going wrong making the call to `write_bat`. Otherwise move the print statements (or add new ones) to pin down where things are hanging. Note that I’ve _never_ observed any issue with buffering of stdout on linux in this type of usage (i.e., I don’t think the flush is necessary). When you pin down the offending line report back. **A side remark** : In looking over your code I happened to notice this line ```fortran medb=Sbathy(fcu,fg(this_image()),this_image()) ``` Where the RHS is a structure constructor expression. You may have the impression (from C++) that this is doing an in-place definition of the `medb` LHS variable; I did at the beginning. But this isn’t the case. Fortran will create a temporary value for the RHS and then use intrinsic assignment to assign that temporary to `medb` (or a defined assignment if you created one). This probably isn’t really what you want, especially if these are large objects. For this reason I’ve found structure constructors to be far less useful than they appear at first blush. Instead you can modify the structure constructor, making it a type bound subroutine (say `init`), and can replace the assignment with ```fortran call medb%init(fcu,fg(this_image()),this_image()) ```