On Tue, Mar 2, 2010 at 8:04 AM, case <case.biomaps.rutgers.edu> 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
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Received on Tue Mar 02 2010 - 08:00:02 PST
