A request: will it be possible for someone to take the defined IO with a derived type case shown below and try it with stream output on a Linux system, while the “FizzBuzz” values are setup using coarrays? Intel API can be an option for this. And compare it with the Fortran sequential IO with an intrinsic type shown by @Beliavsky in the original post?
use num_string_m, only : num_string_t
character(len=*), parameter :: FIZZBUZZ = "FizzBuzz"
character(len=*), parameter :: FIZZ = "Fizz"
character(len=*), parameter :: BUZZ = "Buzz"
integer, parameter :: N = 1000000000
type(num_string_t), allocatable :: s(:)[:]
logical :: div_3, div_5
integer :: i, x, j, lun, istat
x = N / num_images()
allocate( s(x)[*] )
sync all
do concurrent ( i = 1:x )
j = (this_image()-1)*x + i
div_3 = mod( j, 3 ) == 0
div_5 = mod( j, 5 ) == 0
if ( div_3 .and. div_5 ) then
s(i) = FIZZBUZZ
else if ( div_3 ) then
s(i) = FIZZ
else if ( div_5 ) then
s(i) = BUZZ
else
s(i) = j
end if
end do
sync all
if ( this_image() == 1 ) then
open( newunit=lun, access="stream", form="formatted", status="scratch", iostat=istat )
if ( istat == 0 ) then
do i = 1, num_images()
write( lun, fmt="(*(DT))", advance="no" ) s(:)[i]
end do
end if
end if
end
The code toward the derived type:
Click for code
Module for numstring_t
module num_string_m
type :: num_string_t
private
character(len=digits(0)) :: s
integer :: lens = 0
contains
private
procedure, pass(this) :: assign_s
procedure, pass(this) :: assign_n
procedure, pass(dtv) :: write_s
generic, public :: assignment(=) => assign_s, assign_n
generic, public :: write(formatted) => write_s
end type
contains
elemental subroutine assign_s( this, s )
class(num_string_t), intent(inout) :: this
character(len=*), intent(in) :: s
this%s = s
this%lens = len_trim(this%s)
end subroutine
elemental subroutine assign_n( this, num )
class(num_string_t), intent(inout) :: this
integer, intent(in) :: num
integer :: i, n, rem
n = num
this%s = ""
this%lens = 0
to_s: do i = digits(0), 1, -1
rem = mod( n, 10 )
this%s(i:i) = achar(iachar("0") + rem)
this%lens = this%lens + 1
n = n/10
if ( n == 0 ) exit to_s
end do to_s
this%s = adjustl(this%s)
end subroutine
subroutine write_s( dtv, lun, iotype, vlist, istat, imsg )
! Argument list
class(num_string_t), intent(in) :: dtv
integer, intent(in) :: lun
character(len=*), intent(in) :: iotype
integer, intent(in) :: vlist(:)
integer, intent(out) :: istat
character (len=*), intent(inout) :: imsg
! local variable
character(len=20) :: pfmt
istat = 0
select case ( iotype )
case ( "LISTDIRECTED" )
! No special consideration
write(lun, fmt=*, iostat=istat, iomsg=imsg) dtv%s(:dtv%lens) // new_line("")
case ( "DT" )
! vlist(1) is to be used as the field widths of the
! component of the derived type variable. First set up the format to
! be used for output.
if ( size(vlist) > 0 ) then
write(pfmt,"(*(g0))" ) "(1x,g", vlist(1), ")"
else
pfmt = "(1x,g0)"
end if
write(lun, fmt=pfmt, advance="no", iostat=istat, iomsg=imsg) dtv%s(:dtv%lens) // new_line("")
case ( "NAMELIST" )
! Not supported
istat = 1
imsg = "Namelist option is not yet supported."
return
end select
return
end subroutine
end module
It will be interesting to see how much adversely the performance might be affected when complicated options using modern Fortran are in play.
Also, the determination of the “FizzBuzz” values themselves has gotta be an embarrassingly parallel problem for a processor, so the question is whether a Fortran processor fed with coarrays and aided by DO CONCURRENT gets close achieving it following which it is just a matter of IO of large data.