Re: [AMBER-Developers] configure_openmpi

From: Jason Swails <>
Date: Tue, 2 Mar 2010 11:16:58 -0500

On Tue, Mar 2, 2010 at 10:54 AM, Lachele Foley <> wrote:
> The thing I didn't get, and still don't, is why there is a compile instruction that calls mpif77 on code that contains F90-specific internal text.  That's what, best I could tell from the error messages, happened with my build: mpif77 complained that it was being asked to compile fortran-90 code.  That's what confused me.

Yes, but that's because your mpif77 was truly wrapped around a
compiler that only compiled fortran77 code (g77). f90 compilers can
still compile fortran77 code, so mpif77 is typically wrapped around a
fortran90 capable compiler (go to a compute cluster and type "mpif77
-show" and you'll see that, more than likely, it'll say ifort if it's
available or gfortran or something, rarely will it have a different
compiler than mpif90 has). Thus, it should have no problem compiling
fortran90-specific code. The way configure_openmpi was set up, it
would build mpif77 around ifort, gfortran, or pgf90 based on what was

I think what Professor Case was saying was that some of the components
built for mpif90 (the ones not built for mpif77) were not necessary
for compiling amber, so why not just use mpif77 and not bother with
the extraneous.

All the best,

> :-) Lachele
> --
> B. Lachele Foley, PhD '92,'02
> Assistant Research Scientist
> Complex Carbohydrate Research Center, UGA
> 706-542-0263
> ----- Original Message -----
> From: Jason Swails
> []
> To: AMBER Developers Mailing List
> []
> Sent: Tue, 02 Mar 2010 10:44:16
> -0500
> Subject: Re: [AMBER-Developers] configure_openmpi
>> On Tue, Mar 2, 2010 at 8:04 AM, case <> wrote:
>> > On Tue, Mar 02, 2010, Jason Swails wrote:
>> >>
>> >> I was wondering if there is a specific reason why the
>> >> --disable-mpi-f90 flag was put in configure_openmpi.
>> >
>> > Just to save time in a long compile, and to avoid problems that might
>> arise
>> > from a feature we don't use.
>> >
>> >> I've always changed FC from mpif77 to mpif90 simply because
>> >> it feels more natural....
>> >
>> > Well, as a "tester", I'd prefer that you do what users would be doing, so
>> that
>> > if there *are* problems, we find them out as soon as possible.
>> I did occasionally forget to change to mpif90, so I suppose I did test
>> mpif77 occasionally :) (though I never built lam or openmpi that came
>> bundled since i prefer my current MPI.  I'm guessing a large number of
>> users will be in this boat, too, though I'm not sure).
>> >
>> >>  the recent change in configure from mpif77 to mpif90.
>> >
>> > OK, I give up.  Ross doesn't understand this, and Lachele doesn't, and
>> you
>> > don't.  I guess I can't expect users not to be confused.  Go ahead and
>> update
>> Given your explanation above, I don't think it's terribly hard to
>> understand.  A downside of using mpif77, though, is if someone built
>> their own MPI before trying to compile amber.  If someone has the
>> intel compiler suite and naively (like I did when I first started, and
>> I think like Lachele did when her mpif77 pointed to g77) used
>> (configure; make; make install) without specifying F77, F90, and CC
>> beforehand, the configure script will attempt to use a .real. F77
>> compiler.  Thus, mpif77 pointed at gfortran/g77 while mpif90 pointed
>> at ifort and mpicc pointed at icc (all by default).  mpif77 then
>> failed to build amber after running ./configure -mpi intel since
>> gfortran didn't recognize all the intel flags, but mpif90 worked.
>> Since this happened to me, I obviously think this would be the issue
>> more users would have (with their own MPIs rather than the ones we
>> provide), but again my experience is very limited and I could be
>> completely wrong.
>> There are trade-offs to either choice, and with my limited experience
>> I'm hardly qualified to provide suggest a definitive *better* option.
>> I'll update configure_openmpi to maintain consistency with the current
>> version of configure, though this can be changed back if it's decided
>> the alternative is the better option.  My main concern was the change
>> in configure that would make compilation fail with the built-in
>> openmpi.
>> > configure_openmpi.
>> >
>> > ....dac
>> All the best,
>> Jason
>> --
>> ---------------------------------------
>> Jason M. Swails
>> Quantum Theory Project,
>> University of Florida
>> Ph.D. Graduate Student
>> 352-392-4032
>> _______________________________________________
>> AMBER-Developers mailing list
> _______________________________________________
> AMBER-Developers mailing list

Jason M. Swails
Quantum Theory Project,
University of Florida
Ph.D. Graduate Student
AMBER-Developers mailing list
Received on Tue Mar 02 2010 - 08:30:03 PST
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