Hi Jason,
This answered my question.
Thanks
On Fri, Mar 16, 2012 at 8:38 AM, Jason Swails <jason.swails.gmail.com>wrote:
> On Fri, Mar 16, 2012 at 9:23 AM, Carlos Sosa <sosa0006.r.umn.edu> wrote:
>
> > Hello,
> >
> > AMBER11 uses MPI_ALLREDUCE. Is it use with 32 bit words or 64? I am
> > currently checking the code as well.
> >
>
> I'm not sure I understand the question. Every MPI call takes an
> MPI_Datatype (e.g. MPI_DOUBLE_PRECISION, MPI_REAL, MPI_INT for Fortran or
> MPI_DOUBLE, MPI_LONG_INT, etc. for C/C++). The size of the MPI_Datatype is
> what MPI uses to assign variables properly in all function calls that pass
> information (including the allreduce). The way it's implemented should be
> platform-independent, so it should work with both 32-bit and 64-bit words.
>
> The aim for sander was to use a preprocessor define, MPI_AMBER_REAL or
> something, that could be toggled to single or double precision, much like
> the preprocessor define _REAL_ can switch between real and double
> precision. MPI_DOUBLE_PRECISION is hard-coded in too many places for the
> single-precision build to work anymore, not that it is recommended, anyway.
>
> HTH,
> Jason
>
>
> > Thanks
> >
> > --
> > Carlos P Sosa, Ph.D.
> > Computational Chemistry Consultant and Adjunct Assistant Professor
> > *Biomedical Informatics and Computational Biology (BICB) *
> > Minnesota Supercomputing Institute for Advanced Computational Research,
> > University of Minnesota, Walters Library # 509, 117 Pleasant Street,
> > Minneapolis, MN 55455.
> > _______________________________________________
> > AMBER mailing list
> > AMBER.ambermd.org
> > http://lists.ambermd.org/mailman/listinfo/amber
> >
>
>
>
> --
> Jason M. Swails
> Quantum Theory Project,
> University of Florida
> Ph.D. Candidate
> 352-392-4032
> _______________________________________________
> AMBER mailing list
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> http://lists.ambermd.org/mailman/listinfo/amber
>
--
Carlos P Sosa, Ph.D.
Computational Chemistry Consultant and Adjunct Assistant Professor
*Biomedical Informatics and Computational Biology (BICB) *
Minnesota Supercomputing Institute for Advanced Computational Research,
University of Minnesota, Walters Library # 509, 117 Pleasant Street,
Minneapolis, MN 55455.
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Received on Fri Mar 16 2012 - 10:00:05 PDT
