topic Re: constructor for empty arrays in Intel® Fortran Compiler

constructor for empty arrays

kolber__Michael — Thu, 06 Aug 2020 17:59:57 GMT

I am working on an example using classes from the Guide to Fortran 2008 Programming. I want to see if classes will help in what I am trying to do. I have worked with classes in other languages .

Here is the part of the code that I get an error from.

module v_q_module
use vehicle_module
implicit none
private

type :: node_type
class(vehicle_type), allocatable :: v
end type node_type

type, public :: q_type
private
type(node_type), dimension(:), allocatable :: vehicles
contains
procedure :: empty, is_empty, insert, remove, print_licenses
end type q_type
contains
subroutine empty(q)
class(q_type), intent(out) :: q
q%vehicles = [ node_type :: ]
end subroutine empty
end module v_q_module

The error is the following:

C:\Michael\traffic_simulation\traffic_simulation\module2.f90(19): error #5082: Syntax error, found '::' when expecting one of: , : (/ ]
C:\Michael\traffic_simulation\traffic_simulation\module2.f90(19): error #6478: A type-name must not be used as a variable. [NODE_TYPE]
compilation aborted for C:\Michael\traffic_simulation\traffic_simulation\module2.f90 (code 1)

All the reading I have done tells me that this line should be a valid statement.

q%vehicles = [ node_type :: ]

Thanks.

Michael

Re: constructor for empty arrays

FortranFan — Thu, 06 Aug 2020 18:55:15 GMT

It is a bug in Intel Fortran compiler, please submit a support request if you can at Intel Online Service Center.

A couple of suggestions:

Try another compiler or two if you can to guide your learning of modern Fortran e.g., open-source gfortran (https://gcc.gnu.org/wiki/GFortran) and if possible, another commercial compiler - see point 2,
Consider participating in Fortran language discourse at https://fortran-lang.discourse.group/. where you can find more options and resources re: Fortran and other compilers, etc..

Note this variant below of your code in the original post. It works as I expect using gfortran:

module vehicle_module type :: vehicle_type end type end module module v_q_module use vehicle_module implicit none private type :: node_type class(vehicle_type), allocatable :: v end type node_type type, public :: q_type private type(node_type), dimension(:), allocatable :: vehicles contains procedure :: empty, get_num_vehicles end type q_type contains subroutine empty(q) class(q_type), intent(out) :: q q%vehicles = [ node_type :: ] end subroutine empty function get_num_vehicles(q) result(num) class(q_type), intent(in) :: q integer :: num num = 0 if ( allocated(q%vehicles) ) num = size(q%vehicles) end function end module v_q_module use v_q_module type(q_type) :: foo call foo%empty() print *, "number of vehicles in foo = ", foo%get_num_vehicles(), "; expected is 0." end

number of vehicles in foo = 0 ; expected is 0.

Re: constructor for empty arrays

kolber__Michael — Thu, 06 Aug 2020 19:16:52 GMT

FortranFan,

Thanks for the advice. I would have to do the extra stuff at home. We are bound to the Intel complier at work. This project is something that I am doing to make a contribution at work when I do not have an upgrade project for the current application.

Re: constructor for empty arrays

Steve_Lionel — Thu, 06 Aug 2020 21:36:26 GMT

I remember reporting a similar bug a long time ago. I wonder what's different about this case?

Re: constructor for empty arrays

IanH — Thu, 06 Aug 2020 22:20:09 GMT

The passing of roughly eight years!

Re: constructor for empty arrays

FortranFan — Thu, 06 Aug 2020 22:30:58 GMT

@kolber__Michael wrote: .. We are bound to the Intel complier at work. This project is something that I am doing to make a contribution at work when I do not have an upgrade project for the current application

You can consider a workaround based on an "original" facility in Fortran for dynamic memory i.e., the ALLOCATE statement:

allocate( q%vehicles(0) )

Re: constructor for empty arrays

Ron_Green — Fri, 07 Aug 2020 02:57:10 GMT

This is fixed in the nightly builds here for the ifort BETA in the oneAPI HPC Toolkit. It's still a bug in the current beta08 release of this kit. But the nightly build which is going into the oneAPI HPC Toolkit for the next beta, beta09, has this working:

rwgreen:~/quad/u1198085$ module load comp/nightlybuild rwgreen:~/quad/u1198085$ ifort -O0 -what -o repro repro.f90 Intel(R) Fortran 2021.1-1898 rwgreen@orcsle156:~/quad/u1198085$ ./repro number of vehicles in foo = 0 ; expected is 0. rwgreen:~/quad/u1198085$ cat repro.f90 module vehicle_module type :: vehicle_type end type end module module v_q_module use vehicle_module implicit none private type :: node_type class(vehicle_type), allocatable :: v end type node_type type, public :: q_type private type(node_type), dimension(:), allocatable :: vehicles contains procedure :: empty, get_num_vehicles end type q_type contains subroutine empty(q) class(q_type), intent(out) :: q q%vehicles = [ node_type :: ] end subroutine empty function get_num_vehicles(q) result(num) class(q_type), intent(in) :: q integer :: num num = 0 if ( allocated(q%vehicles) ) num = size(q%vehicles) end function end module v_q_module use v_q_module type(q_type) :: foo call foo%empty() print *, "number of vehicles in foo = ", foo%get_num_vehicles(), "; expected is 0." end