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Subject: Re: [OMPI devel] Wrong Endianness in Open MPI for external32 representation
From: Edgar Gabriel (gabriel_at_[hidden])
Date: 2014-04-29 09:27:16


the way you launch the app, you will be using ROMIO, and I am not 100%
sure about how the data representation stuff is integrated with OMPI. I
am pretty sure that we are not doing the right thing for OMPIO, but I
will look into later this week.

Thanks
Edgar

On 4/29/2014 7:03 AM, Christoph Niethammer wrote:
> Hello,
>
> It seems for me that the endianness is wrong in Open MPI's I/O for the external32 data representation. :O
>
> Find attached my test programs which write the integer -30 and the double 16.25 into a file.
> Here the output on my Linux system:
>
> mpicc c-xdr.c -o c-xdr
> mpicc mpi-io-external32.c -o mpi-io-external32
> ./c-xdr
> Output file: c-xdr.dat
> hexdump c-xdr.dat
> 0000000 ffff e2ff 3040 0040 0000 0000
> 000000c
> ./mpi-io-external32
> Output file: mpi-io-external32.dat
> hexdump mpi-io-external32.dat
> 0000000 ffe2 ffff 0000 0000 4000 4030
> 000000c
>
>
> Best regards
> Christoph Niethammer
>
> --
>
> Christoph Niethammer
> High Performance Computing Center Stuttgart (HLRS)
> Nobelstrasse 19
> 70569 Stuttgart
>
> Tel: ++49(0)711-685-87203
> email: niethammer_at_[hidden]
> http://www.hlrs.de/people/niethammer
>
>
>
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>

-- 
Edgar Gabriel
Associate Professor
Parallel Software Technologies Lab      http://pstl.cs.uh.edu
Department of Computer Science          University of Houston
Philip G. Hoffman Hall, Room 524        Houston, TX-77204, USA
Tel: +1 (713) 743-3857                  Fax: +1 (713) 743-3335