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Subject: Re: [OMPI users] Prototypes for Fortran MPI_ commands using 64-bit indexing
From: Ralph Castain (rhc_at_[hidden])
Date: 2013-10-30 16:40:47


I believe this has been a long-standing issue with the MPI definitions - they specify "int", which on most systems will default to int32_t. Thus, there are no prototypes for 64-bit interfaces

On Oct 30, 2013, at 1:35 PM, Jim Parker <jimparker96313_at_[hidden]> wrote:

> Hello,
> I have recently built a cluster that uses the 64-bit indexing feature of OpenMPI following the directions at
> http://wiki.chem.vu.nl/dirac/index.php/How_to_build_MPI_libraries_for_64-bit_integers
>
> My question is what are the new prototypes for the MPI calls ?
> specifically
> MPI_RECV
> MPI_Allgathterv
>
> I'm curious because some off my local variables get killed (set to null) upon my first call to MPI_RECV. Typically, this is due (in Fortran) to someone not setting the 'status' variable to an appropriate array size.
>
> However, my declaration for status is
> integer (kind=mpi_int_kind) :: status(MPI_STATUS_SIZE)
>
> A typical call to MPI_Recv is
> call MPI_RECV(num_array, length, MPI_INTEGER, 0,0,MPI_COMM_WORLD, status, mpierr)
>
> where the following definitions are used,
> mpi_int_kind=8 (for gcc/gfortran compiler)
>
> integer,parameter :: length = <some-value>
> integer :: num_array(length)
> integer :: mpierr
>
> My review of mpif.h and mpi.h seem to indicate that the functions are defined as C int types and therefore , I assume, the coercion during the compile makes the library support 64-bit indexing. ie. int -> long int
>
> The documentation on MPI_Recv just mentions the prototype for ints (32-bit) , I can't find anything for 64-bit
> http://www.open-mpi.org/doc/v1.6/
>
> Any help would be appreciated.
> The output from ompi_info --all is attached.
>
> Cheers,
> --Jim Parker
>
> BTW, the code works fine when linked against a 32-bit MPI library.
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