[MITgcm-support] adjoint compilation on 64bit system

[Patrick Heimbach]

Hi Martin,

you know I'm not a compiler guy, so the following
might be complete nonsense:

Quite a few adjoint routines contain loop inversions,
in particular w.r.t. K.
You'll see for adconvective_adjustment that the forward loop
          DO K=kTop,kBottom,kDir
gets transformed into
        do k = ktop+kdir*(int((kbottom-ktop+kdir)/kdir)-1), ktop, -kdir
(which of course is the same as do k = kbottom,ktop,-kdir).

I suspect that this gives the compiler optimization a few headaches.
One way to check is to see whether S/R mdconvective_adjustment
has the same problems. It does access the same tapes/common blocks,
but in "forward order".

You could also check, what effect has replacing
        do k = ktop+kdir*(int((kbottom-ktop+kdir)/kdir)-1), ktop, -kdir
by
        do k = kbottom, ktop, -kdir

Re. S/R barrier.F, try to put this routine in the NOOPTFILES list.

-p.



On Thursday 24 February 2005 05:11, Martin Losch wrote:
  > Hi,
  >
  > I am trying to compile the adjoint MITgcm on an AMD 64bit opteron
  > machine with the Portland Group fortran compiler. I have no problems
  > with my build options file linux_amd64_pgf77_ocl (that I am responsible
  > for anyway) as long as I don't ALLOW_ECCO_ADJOINT_RUN (in
  > ECCO_CPPOPTIONS.h), but use ALLOW_ECCO_FORWARD_RUN. But as soon as
  > there is the adjoint model involved (ad_taf_output.f) I get funny error
  >
  > messages at the link step:
  > > ad_taf_output.o: In function `adconvective_adjustment_':
  > > ad_taf_output.o(.text+0xf018): relocation truncated to fit:
  > > R_X86_64_32S cadtheta_
  > > ad_taf_output.o(.text+0xf038): relocation truncated to fit:
  > > R_X86_64_32S cadtheta_
  > > ad_taf_output.o(.text+0xf4e0): relocation truncated to fit:
  > > R_X86_64_32S cadthetb_
  > > ad_taf_output.o(.text+0xf501): relocation truncated to fit:
  > > R_X86_64_32S cadthetb_
  >
  > (most of them concern common blocks defined in ad_taf_output.f for the
  >
  > tapes) but also:
  > > /var/tmp.shared/pgi/linux86-64/5.2/lib/libpgc.a(barrier.o): In
  > > function `_mp_get_parpar':
  > > barrier.o(.text+0x69): relocation truncated to fit: R_X86_64_32S
  > > _mp_parpar
  > > /var/tmp.shared/pgi/linux86-64/5.2/lib/libpgc.a(barrier.o): In
  > > function `_mp_lcpu2':
  > > barrier.o(.text+0x34e): relocation truncated to fit: R_X86_64_32S
  > > _mp_parpar
  >
  > which doesn't have anything to do with ad_taf_output.f
  > These errors go away when I use an additional optiong: -fpic, which
  > according to the man pages "(Linux only) Instructs the compiler to
  > generate position-independent code with can be used to create shared
  > object files ..."
  >
  > I don't see why the TAMC/TAF generated code should need this option
  > while the remaining part of the code doesn't need it. Any ideas?
  >
  > Martin
  >
  >
  > _______________________________________________
  > MITgcm-support mailing list
  > MITgcm-support at mitgcm.org
  > http://dev.mitgcm.org/mailman/listinfo/mitgcm-support

-- 
----------------------------------------------------------
Patrick Heimbach     Massachusetts Institute of Technology
FON: +1/617/253-5259                    EAPS, Room 54-1518
FAX: +1/617/253-4464               77 Massachusetts Avenue
mailto:heimbach at mit.edu                 Cambridge MA 02139
http://www.mit.edu/~heimbach/                          USA