[SOLVED] Why does coarray with allocatable component creates segmentation faults when accessed from different image?

Why does coarray with allocatable component creates segmentation faults when accessed from different image?

I want to use the fortran coarray feature to have different size arrays on different images.

Following the 2008/2018 standard, this should be possible by using a derived type containing an allocatable. I am using gfortran 8.2.0 with opencoarrays 2.3.1.1 MPI library on macOS Mojave.

program Main
    implicit none

    type :: Array_Type
        double precision, dimension(:), allocatable :: values
    end type
    type(Array_Type), codimension[*] :: array

    if(this_image() == 1) then
        allocate(array%values(2))
        array%values = this_image()
    else
        allocate(array%values(1))
    endif
    sync all

    print *, this_image(), array[1]%values(:)
    sync all
end program

The program is compiled by

gfortran -Wall -fcoarray=lib Main.f90 -lcaf_mpi

An even simpler example leads to the same segmentation fault when the allocated array is accessed by other images.

program Main
    implicit none

    type :: Array_Type
        double precision, dimension(:), allocatable :: values
    end type
    type(Array_Type), codimension[*] :: array

    allocate(array%values(2))
    sync all

    print *, this_image(), array[1]%values(:)
    sync all
end program

Solution

Solution

The code works correctly with the specified system as long as MPICH instead of the default OpenMpi is used with OpenCoarrays.

Additionally, the OpenCoarrays compiler wrapper should be used: caf Main.f90

I opened an issue at the OpenCoarrays GitHub site: https://github.com/sourceryinstitute/OpenCoarrays/issues/625