This is more an illustration

Colin_W_1 · ‎02-08-2020

Does the standard allow a coarray to be a UDT type with allocatable components? From note 5.6 in the 2008 standard, the answer appears to be "yes":

A coarray is permitted to be of a derived type with pointer or allocatable components. The target of such
a pointer component is always on the same image as the pointer.

The same note appears in the 2018 standard, as note 1 in section 8.5.6.

OK, so if the component in question is a pointer component, it points to a target in the same image as the pointer. But what about when its an allocatable component? And, crucially for my work, what happens when the coarray is referenced from a different image?

In my work I am trying to copy coarray elements between images. I find that, if the UDT does not contain allocatable components, the copy works correctly, but not when it does.

If necessary I can knock up an example to show what I mean. But I don't want to do that if my understanding of the standard is incorrect.

I am using IVF 17.0.2.187 and 19.1.0.166.

FortranFan · ‎02-08-2020

Colin W. wrote:
.. In my work I am trying to copy coarray elements between images. I find that, if the UDT does not contain allocatable components, the copy works correctly, but not when it does. ..
I am using IVF .. 19.1.0.166.

Submit a support request with Intel Online Service Center (OSC) if you're able to: https://supporttickets.intel.com/servicecenter?lang=en-US

My understanding is what you're doing is alright by the standard, especially with a component with the ALLOCATABLE attribute in a derived type and with copying data from another image in a coarray object of such a derived type. The issue(s) you face is likely more due to an implementation matter. Intel support can then hopefully guide you best.

FortranFan · ‎02-08-2020

This is more an illustration of a quick check and for any other readers wanting to try out coarrays in Fortran with a derived type that has an ALLOCATABLE component:

   type :: t
      integer, allocatable :: n
   end type
   character(len=*), parameter :: fmtg = "(g0,t15,g0)"

   type(t), save :: foo
   integer :: i

   if ( this_image() == 1 ) then
      foo%n = 42
   end if
   sync all

   if ( this_image() /= 1 ) then
      foo%n = foo[1]%n + this_image() - 1
   end if
   sync all

   if ( this_image() == 1 ) then
      print fmtg, "Image #", "foo%n"    
      do i = 1, num_images()
         print fmtg, i, foo%n
      end do
   end if

end

C:\Temp>ifort /standard-semantics /warn:all /stand:f18 /Qcoarray:shared /Qcoarray-num-images=8 p.f90
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 19.1.0.166 Build 20191121
Copyright (C) 1985-2019 Intel Corporation.  All rights reserved.

Microsoft (R) Incremental Linker Version 14.24.28316.0
Copyright (C) Microsoft Corporation.  All rights reserved.

-out:p.exe
-subsystem:console
p.obj

C:\Temp>p.exe
Image #       foo%n
1             42
2             43
3             44
4             45
5             46
6             47
7             48
8             49
C:\Temp>

Colin_W_1 · ‎02-08-2020

program test

   type :: t
      real(8)              :: x1, x2, x3
      real(8), allocatable :: xn(:)
      integer              :: i1, i2, i3
      integer, allocatable :: in(:)
   end type

   type(t), save :: foo

   if ( this_image() == 1 ) then
      foo%x1 = 20.
      foo%x2 = 30.
      foo%x3 = 40.
      foo%xn = [41., 42., 43., 44.]
      foo%i1 = 11
      foo%i2 = 21
      foo%i3 = 31
      foo%in = [51, 52, 53, 54]
   end if
   sync all

   if ( this_image() /= 1 ) then
      foo = foo[1]
   end if
   sync all

   print *,' image ',this_image(), foo%x1, &
                                   foo%x1, &
                                   foo%x2, &
                                   foo%x3, &
                                   foo%xn, &
                                   foo%i1, &
                                   foo%i2, &
                                   foo%i3, &
                                   foo%in

end

With IVF 17.0.2.187 and for_coarray_num_images=2, the run either crashes, or gives the wrong answer for the allocatables:

C:\prog\test\co\x64\Debug>co
  image            2   20.0000000000000        20.0000000000000
  image            1   20.0000000000000        20.0000000000000
   30.0000000000000        40.0000000000000        41.0000000000000
   42.0000000000000        43.0000000000000        44.0000000000000
          11          21          31          51          52          53
          54
   30.0000000000000        40.0000000000000       0.000000000000000E+000
  0.000000000000000E+000  0.000000000000000E+000  0.000000000000000E+000
          11          21          31           0           0           0
           0

C:\prog\test\co\x64\Debug>co
forrtl: severe (157): Program Exception - access violation
In coarray image 2
Image              PC                Routine            Line        Source
VCRUNTIME140D.dll  000007FEBB401330  Unknown               Unknown  Unknown
co.exe             000000013FF61F2C  MAIN__                     26  eg.f90
co.exe             000000013FF62A2E  Unknown               Unknown  Unknown
co.exe             000000013FF64404  Unknown               Unknown  Unknown
co.exe             000000013FF64317  Unknown               Unknown  Unknown
co.exe             000000013FF641DE  Unknown               Unknown  Unknown
co.exe             000000013FF64419  Unknown               Unknown  Unknown
kernel32.dll       000000007718556D  Unknown               Unknown  Unknown
ntdll.dll          00000000773E372D  Unknown               Unknown  Unknown

application called MPI_Abort(comm=0x84000002, 0) - process 1

C:\prog\test\co\x64\Debug>co
  image            2   20.0000000000000        20.0000000000000
  image            1   20.0000000000000        20.0000000000000
   30.0000000000000        40.0000000000000        41.0000000000000
   42.0000000000000        43.0000000000000        44.0000000000000
          11          21          31          51          52          53
          54
   30.0000000000000        40.0000000000000       3.250556697118729E-318
  0.000000000000000E+000  0.000000000000000E+000  0.000000000000000E+000
          11          21          31           0           0           0
           0

C:\prog\test\co\x64\Debug>co
forrtl: severe (157): Program Exception - access violation
In coarray image 2
Image              PC                Routine            Line        Source
VCRUNTIME140D.dll  000007FEBB401330  Unknown               Unknown  Unknown
co.exe             000000013F2D1F2C  MAIN__                     26  eg.f90
co.exe             000000013F2D2A2E  Unknown               Unknown  Unknown
co.exe             000000013F2D4404  Unknown               Unknown  Unknown
co.exe             000000013F2D4317  Unknown               Unknown  Unknown
co.exe             000000013F2D41DE  Unknown               Unknown  Unknown
co.exe             000000013F2D4419  Unknown               Unknown  Unknown
kernel32.dll       000000007718556D  Unknown               Unknown  Unknown
ntdll.dll          00000000773E372D  Unknown               Unknown  Unknown

application called MPI_Abort(comm=0x84000002, 0) - process 1

C:\prog\test\co\x64\Debug>co
forrtl: severe (157): Program Exception - access violation
In coarray image 2
Image              PC                Routine            Line        Source
VCRUNTIME140D.dll  000007FEBB791330  Unknown               Unknown  Unknown
co.exe             000000013FED1F2C  MAIN__                     26  eg.f90
co.exe             000000013FED2A2E  Unknown               Unknown  Unknown
co.exe             000000013FED4404  Unknown               Unknown  Unknown
co.exe             000000013FED4317  Unknown               Unknown  Unknown
co.exe             000000013FED41DE  Unknown               Unknown  Unknown
co.exe             000000013FED4419  Unknown               Unknown  Unknown
kernel32.dll       000000007718556D  Unknown               Unknown  Unknown
ntdll.dll          00000000773E372D  Unknown               Unknown  Unknown

application called MPI_Abort(comm=0x84000002, 0) - process 1

C:\prog\test\co\x64\Debug>co
  image            1   20.0000000000000        20.0000000000000
  image            2   20.0000000000000        20.0000000000000
   30.0000000000000        40.0000000000000       0.000000000000000E+000
  0.000000000000000E+000  0.000000000000000E+000  0.000000000000000E+000
          11          21          31           0           0           0
           0
   30.0000000000000        40.0000000000000        41.0000000000000
   42.0000000000000        43.0000000000000        44.0000000000000
          11          21          31          51          52          53
          54

C:\prog\test\co\x64\Debug>

With 19.1.0.166 I get an ICE:

1>------ Rebuild All started: Project: co, Configuration: Debug x64 ------
1>Deleting intermediate files and output files for project 'co', configuration 'Debug|x64'.
1>Compiling with Intel(R) Visual Fortran Compiler 19.1.0.166 [Intel(R) 64]...
1>eg.f90
1>04010002_1529
1>C:\prog\test\co\eg.f90(26): catastrophic error: **Internal compiler error: internal abort** Please report this error along with the circumstances in which it occurred in a Software Problem Report.  Note: File and line given may not be explicit cause of this error.
1>compilation aborted for C:\prog\test\co\eg.f90 (code 1)
1>
1>Build log written to  "file://C:\prog\test\co\x64\Debug\BuildLog.htm"
1>co - 1 error(s), 0 warning(s)
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

FortranFan · ‎02-09-2020

Well, that's a shame on the compiler. Component-by-component assignments work: Intel Fortran compiler implementation appears to have issues with intrinsic assignment of derived types with ALLOCATABLE components in a coarray context and your support request here will hopefully get the Intel Fortran team to improve this aspect of their implementation.

   type :: t
      real(8)              :: x1, x2, x3
      real(8), allocatable :: xn(:)
      integer              :: i1, i2, i3
      integer, allocatable :: in(:)
   end type
   character(len=*), parameter :: fmtg = "(g0,t15,g0,t35,*(g0,1x))"

   type(t), save :: foo
   integer :: i

   if ( this_image() == 1 ) then
      foo%x1 = 20.
      foo%x2 = 30.
      foo%x3 = 40.
      foo%xn = [41., 42., 43., 44.]
      foo%i1 = 11
      foo%i2 = 21
      foo%i3 = 31
      foo%in = [51, 52, 53, 54]
   end if
   sync all

   if ( this_image() /= 1 ) then
      foo%x1 = foo[1]%x1
      foo%x2 = foo[1]%x2
      foo%x3 = foo[1]%x3
      foo%xn = foo[1]%xn
      foo%i1 = foo[1]%i1
      foo%i2 = foo[1]%i2
      foo%i3 = foo[1]%i3
      foo%in = foo[1]%in
   end if
   sync all

   if ( this_image() == 1 ) then
      print fmtg, "Image #", "foo%x1", "foo%in"    
      do i = 1, num_images()
         print fmtg, i, foo%x1, foo%in
      end do
   end if

end

C:\Temp>ifort /standard-semantics /warn:all /stand:f18 /Qcoarray:shared /Qcoarray-num-images=8 p.f90
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 19.1.0.166 Build 20191121
Copyright (C) 1985-2019 Intel Corporation.  All rights reserved.

Microsoft (R) Incremental Linker Version 14.24.28316.0
Copyright (C) Microsoft Corporation.  All rights reserved.

-out:p.exe
-subsystem:console
p.obj

C:\Temp>p.exe
Image #       foo%x1              foo%in
1             20.00000000000000   51 52 53 54
2             20.00000000000000   51 52 53 54
3             20.00000000000000   51 52 53 54
4             20.00000000000000   51 52 53 54
5             20.00000000000000   51 52 53 54
6             20.00000000000000   51 52 53 54
7             20.00000000000000   51 52 53 54
8             20.00000000000000   51 52 53 54

C:\Temp>

But now, an ICE is always a compiler bug so Intel Fortran team should immediately accept that as a legitimate issue to work on.

FortranFan · ‎02-09-2020

Hopefully the couple of examples shown below can be reviewed by Intel Fortran team for consideration of cases toward their library of quality assurance (QA) and acceptance and validation checks of modern Fortran feature implementations such as coarrays and later toward their test suite for regression testing. That is, assuming such test libraries/suites are even present, at times one really has to wonder considering the defects that show up as to whether the vendor even bothers to do basic checks of their own with the implemented functionality or relies entirely on the users to discover the problems.

Example 1: defined assignment works with a simple derived type:

module m

   type :: t
      integer :: n = 0
   contains
      procedure, pass(lhs) :: assign_t
      generic :: assignment(=) => assign_t
   end type

contains

   elemental subroutine assign_t( lhs, rhs )
      class(t), intent(inout) :: lhs
      type(t), intent(in)     :: rhs
      lhs%n = rhs%n
   end subroutine

end module
 
   use m, only : t 
   character(len=*), parameter :: fmtg = "(g0,t15,g0)"

   type(t), save :: foo
   integer :: i

   if ( this_image() == 1 ) then
      foo%n = 42
   end if
   sync all

   if ( this_image() /= 1 ) then
      foo = foo[1]
   end if
   sync all

   if ( this_image() == 1 ) then
      print fmtg, "Image #", "foo%n"    
      do i = 1, num_images()
         print fmtg, i, foo%n
      end do
   end if

end

Example 2: change the component in example 1 above to have an ALLOCATABLE attribute and the program does not work.

module m

   type :: t
      integer, allocatable :: n
   contains
      procedure, pass(lhs) :: assign_t
      generic :: assignment(=) => assign_t
   end type

contains

   elemental subroutine assign_t( lhs, rhs )
      class(t), intent(inout) :: lhs
      type(t), intent(in)     :: rhs
      lhs%n = rhs%n
   end subroutine

end module
 
   use m, only : t 
   character(len=*), parameter :: fmtg = "(g0,t15,g0)"

   type(t), save :: foo
   integer :: i

   if ( this_image() == 1 ) then
      foo%n = 42
   end if
   sync all

   if ( this_image() /= 1 ) then
      foo = foo[1]
   end if
   sync all

   if ( this_image() == 1 ) then
      print fmtg, "Image #", "foo%n"    
      do i = 1, num_images()
         print fmtg, i, foo%n
      end do
   end if

end

C:\Temp>ifort /standard-semantics /warn:all /stand:f18 /Qcoarray:shared /Qcoarray-num-images=8 p.f90
Intel(R) Visual Fortran Intel(R) 64 Compiler for applications running on Intel(R) 64, Version 19.1.0.166 Build 20191121
Copyright (C) 1985-2019 Intel Corporation.  All rights reserved.

Microsoft (R) Incremental Linker Version 14.24.28316.0
Copyright (C) Microsoft Corporation.  All rights reserved.

-out:p.exe
-subsystem:console
p.obj

C:\Temp>p.exe
forrtl: severe (157): Program Exception - access violation
In coarray image 6
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 3
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 5
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 4
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 8
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 7
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown

forrtl: severe (157): Program Exception - access violation
In coarray image 2
Image              PC                Routine            Line        Source
p.exe              00007FF6BE801176  Unknown               Unknown  Unknown
p.exe              00007FF6BE858E5E  Unknown               Unknown  Unknown
p.exe              00007FF6BE8591E0  Unknown               Unknown  Unknown
KERNEL32.DLL       00007FFBBB8137E4  Unknown               Unknown  Unknown
ntdll.dll          00007FFBBBE3CB81  Unknown               Unknown  Unknown


C:\Temp>

Coarrays of UDTs with Allocatable components