From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugzilla@gcc.gnu.org>
Received: by sourceware.org (Postfix, from userid 48)
 id 8E2C8388C03A; Sat, 12 Dec 2020 18:20:44 +0000 (GMT)
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 8E2C8388C03A
From: "kargl at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug fortran/98253] Conflicting random_seed/random_init results
Date: Sat, 12 Dec 2020 18:20:44 +0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: fortran
X-Bugzilla-Version: 11.0
X-Bugzilla-Keywords: 
X-Bugzilla-Severity: normal
X-Bugzilla-Who: kargl at gcc dot gnu.org
X-Bugzilla-Status: UNCONFIRMED
X-Bugzilla-Resolution: 
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags: 
X-Bugzilla-Changed-Fields: 
Message-ID: <bug-98253-4-We9lynqa9J@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-98253-4@http.gcc.gnu.org/bugzilla/>
References: <bug-98253-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-BeenThere: gcc-bugs@gcc.gnu.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Gcc-bugs mailing list <gcc-bugs.gcc.gnu.org>
List-Unsubscribe: <https://gcc.gnu.org/mailman/options/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=unsubscribe>
List-Archive: <https://gcc.gnu.org/pipermail/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-request@gcc.gnu.org?subject=help>
List-Subscribe: <https://gcc.gnu.org/mailman/listinfo/gcc-bugs>,
 <mailto:gcc-bugs-request@gcc.gnu.org?subject=subscribe>
X-List-Received-Date: Sat, 12 Dec 2020 18:20:44 -0000

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D98253

--- Comment #3 from kargl at gcc dot gnu.org ---
Third thought.  Here are the programs you meant to write (without error
checking such as how_to_use_random_init must be run before
how_to_seed_with_random_seed_like_random_init).

program how_to_use_random_init

   implicit none

   integer fd, i, n
   integer, allocatable :: seeds(:)
   real r

   call random_init(repeatable=3D.true., image_distinct=3D.true.)

   call random_seed(size=3Dn)
   allocate(seeds(n))
   call random_seed(get=3Dseeds)
   open(newunit=3Dfd,file=3D'seed.cache',access=3D'stream',status=3D'replac=
e')
   write(fd) seeds
   close(fd)

   do i=3D1,5
     call random_number(r)
     print *,r=20
   end do

end program how_to_use_random_init

program how_to_seed_with_random_seed_like_random_init

   implicit none

   integer fd, i, n
   integer, allocatable :: seeds(:)
   real r

   call random_seed(size=3Dn)
   allocate(seeds(n))
   open(newunit=3Dfd,file=3D'seed.cache',access=3D'stream',status=3D'old')
   read(fd) seeds
   close(fd)

   call random_seed(put=3Dseeds)
   do i=3D1,5
      call random_number(r)
      print *,r=20
   end do

end program how_to_seed_with_random_seed_like_random_init=