# Using an array constructor in do concurrent **URL:** \ **Category:** Help\ **Created:** [June 23, 2022, 9:10pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824 "2022-06-23T21:10:59Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![han190](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/han190/32/7158_2.png) [@han190](https://fortran-lang.discourse.group/u/han190)\ **Post date:** [June 23, 2022, 9:10pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/1 "2022-06-23T21:10:59Z")
For a simple program ```fortran program main implicit none integer :: i, j, idx(2) do concurrent (j=1:5, i=1:5) idx = [i, j] ! idx(1) = i; idx(2) = j ! This works. end do end program main ``` Compile and run the program with `ifort` ```bash ifort -warn all -check all -error-limit 1 -O0 -g -assume byterecl -traceback test.f90 && ./a.out ``` (same flags with `fpm --profile debug --compiler ifort`) leaves me an error ```auto Boundary Run-Time Check Failure for variable 'var$12' forrtl: error (76): Abort trap signal Image PC Routine Line Source a.out 00000000004048CB Unknown Unknown Unknown libc.so.6 00007F444EE1A520 Unknown Unknown Unknown libc.so.6 00007F444EE6EA7C pthread_kill Unknown Unknown libc.so.6 00007F444EE1A476 raise Unknown Unknown libc.so.6 00007F444EE007F3 abort Unknown Unknown a.out 000000000047ADE7 Unknown Unknown Unknown a.out 00000000004039FD MAIN__ 11 test.f90 a.out 00000000004038A2 Unknown Unknown Unknown libc.so.6 00007F444EE01D90 Unknown Unknown Unknown libc.so.6 00007F444EE01E40 __libc_start_main Unknown Unknown a.out 00000000004037A5 Unknown Unknown Unknown Aborted ``` The Intel Fortran compiler I am using is ```auto $ ifort --version ifort (IFORT) 2021.6.0 20220226 Copyright (C) 1985-2022 Intel Corporation. All rights reserved. ``` I must have done something stupid, but I am struggling to find out… ---
**Author:** ![urbanjost](https://avatars.discourse-cdn.com/v4/letter/u/0ea827/32.png) [@urbanjost](https://fortran-lang.discourse.group/u/urbanjost)\ **Post date:** [June 23, 2022, 10:06pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/2 "2022-06-23T22:06:45Z")
Pretty sure I reported that one. Its not you. Try this: ```fortran program main implicit none integer :: i, j, idx(2) do concurrent (j=1:5, i=1:5) write(*,*)[i,j] end do end program main ``` Note ```bash fpm run --compiler ifort --profile release ``` will run. Only manifests with specific sompiler switches ---
**Author:** ![FortranFan](https://avatars.discourse-cdn.com/v4/letter/f/96bed5/32.png) [@FortranFan](https://fortran-lang.discourse.group/u/FortranFan)\ **Post date:** [June 23, 2022, 10:15pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/3 "2022-06-23T22:15:25Z")
Retry without the -check all option. You may also want to post this at the Intel Fortran forum and look for feedback from Intel support with -check option and the cases where this option runs into difficulties. ---
**Author:** ![han190](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/han190/32/7158_2.png) [@han190](https://fortran-lang.discourse.group/u/han190)\ **Post date:** [June 23, 2022, 10:38pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/4 "2022-06-23T22:38:23Z")
Thanks! While I am playing around I found that with `--profile debug --compiler ifort` what also doesn’t work is ```fortran program main implicit none integer :: i, j do concurrent (j=1:5, i=1:5) associate (idx => pair(i, j)) write (*, *) idx end associate end do contains pure function pair(i_, j_) result(ret) integer, intent(in) :: i_, j_ integer :: ret(2) ret = [i_, j_] end function pair end program main ``` The compiler throws me two remarks and a bunch of incorrect indices ```auto test.f90(6): remark #7712: This variable has not been used. [I] do concurrent (j=1:5, i=1:5) ------------------------^ test.f90(6): remark #7712: This variable has not been used. [J] do concurrent (j=1:5, i=1:5) -----------------^ -858993460 -858993460 -858993460 -858993460 -858993460 -858993460 ... ``` I guess I will just use `--profile release` and declare an array `integer :: idx(2)` and assign it explicitly in the loop for now. ---
**Author:** ![urbanjost](https://avatars.discourse-cdn.com/v4/letter/u/0ea827/32.png) [@urbanjost](https://fortran-lang.discourse.group/u/urbanjost)\ **Post date:** [June 23, 2022, 10:39pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/5 "2022-06-23T22:39:40Z")
It was the “-check stack” option that triggered it. ```bash fpm run --compiler ifort -profile debug -flag '-check nostack' ``` "ifort file.f90 -check all " triggers it, and “fpm --profile debug --compiler ifort” uses “-check all”; but if you turn off just “stack” it runs. So the simplest trigger is just “ifort -check stack file.f90”. ---
**Author:** ![han190](https://yyz2.discourse-cdn.com/free1/user_avatar/fortran-lang.discourse.group/han190/32/7158_2.png) [@han190](https://fortran-lang.discourse.group/u/han190)\ **Post date:** [June 23, 2022, 10:44pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/6 "2022-06-23T22:44:56Z")
It seems -check all is a pretty strict flag, which is helpful for me to find bugs, either from me or the compiler. 🙂 ---
**Author:** ![urbanjost](https://avatars.discourse-cdn.com/v4/letter/u/0ea827/32.png) [@urbanjost](https://fortran-lang.discourse.group/u/urbanjost)\ **Post date:** [June 23, 2022, 10:50pm UTC](https://fortran-lang.discourse.group/t/using-an-array-constructor-in-do-concurrent/3824/7 "2022-06-23T22:50:09Z")
🙂 That sums it up nicely. It really is a useful switch which I agree fpm should use in debug mode; but one cannot help but smile in this case when the debug flag adds the bug and then detects it.